TaskList类用于表示任务列表，并提供了一系列方法来处理任务列表的创建、更新、内容设置、同步操作以及子任务的管理。

Contact.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 包声明，定义了这个类所在的包名
+package net.micode.notes.data;
+
+// 导入所需的Android类库
+import android.content.Context;
+import android.database.Cursor;
+import android.provider.ContactsContract.CommonDataKinds.Phone;
+import android.provider.ContactsContract.Data;
+import android.telephony.PhoneNumberUtils;
+import android.util.Log;
+
+// 导入Java的HashMap类，用于存储联系人缓存
+import java.util.HashMap;
+
+// 定义Contact类
+public class Contact {
+    // 定义一个静态的HashMap，用于缓存联系人信息，避免重复查询
+    private static HashMap<String, String> sContactCache;
+    // 定义一个TAG，用于日志输出
+    private static final String TAG = "Contact";
+
+    // 定义一个静态常量，用于构建查询语句
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
+    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+    + " AND " + Data.RAW_CONTACT_ID + " IN "
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+
+    // 定义一个静态方法，用于根据电话号码获取联系人名称
+    public static String getContact(Context context, String phoneNumber) {
+        // 如果缓存不存在，则初始化缓存
+        if(sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+
+        // 如果电话号码已经在缓存中，则直接返回缓存中的联系人名称
+        if(sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 替换查询语句中的占位符，构建具体的查询语句
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 使用ContentResolver查询联系人数据
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,
+                new String [] { Phone.DISPLAY_NAME },
+                selection,
+                new String[] { phoneNumber },
+                null);
+
+        // 如果查询结果不为空，并且至少有一条数据
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                // 获取联系人名称
+                String name = cursor.getString(0);
+                // 将联系人名称放入缓存
+                sContactCache.put(phoneNumber, name);
+                return name;
+            } catch (IndexOutOfBoundsException e) {
+                // 如果获取联系人名称时出现异常，记录错误日志
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                // 最后，关闭游标
+                cursor.close();
+            }
+        } else {
+            // 如果没有匹配的联系人，记录日志并返回null
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}

MetaData.java

@@ -0,0 +1,103 @@
+// 多行注释，说明版权信息和许可证
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的类
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+// MetaData类继承自Task类，用于处理与任务相关的元数据
+public class MetaData extends Task {
+    // 类的标签，用于日志记录
+    private final static String TAG = MetaData.class.getSimpleName();
+
+    // 用于存储相关任务的全局唯一标识符
+    private String mRelatedGid = null;
+
+    // 设置元数据信息
+    public void setMeta(String gid, JSONObject metaInfo) {
+        try {
+            // 将全局唯一标识符添加到元数据信息中
+            metaInfo.put(GTaskStringUtils.META_HEAD_GTASK_ID, gid);
+        } catch (JSONException e) {
+            // 如果添加失败，记录错误日志
+            Log.e(TAG, "failed to put related gid");
+        }
+        // 设置任务的备注信息为元数据的字符串表示
+        setNotes(metaInfo.toString());
+        // 设置任务的名称为特定的元数据任务名称
+        setName(GTaskStringUtils.META_NOTE_NAME);
+    }
+
+    // 获取相关任务的全局唯一标识符
+    public String getRelatedGid() {
+        return mRelatedGid;
+    }
+
+    // 重写isWorthSaving方法，判断任务是否值得保存
+    @Override
+    public boolean isWorthSaving() {
+        // 如果任务的备注信息不为空，则认为值得保存
+        return getNotes() != null;
+    }
+
+    // 从远程JSON对象设置内容
+    @Override
+    public void setContentByRemoteJSON(JSONObject js) {
+        // 首先调用父类的设置内容方法
+        super.setContentByRemoteJSON(js);
+        // 如果备注信息不为空
+        if (getNotes() != null) {
+            try {
+                // 将备注信息转换为JSON对象，并获取全局唯一标识符
+                JSONObject metaInfo = new JSONObject(getNotes().trim());
+                mRelatedGid = metaInfo.getString(GTaskStringUtils.META_HEAD_GTASK_ID);
+            } catch (JSONException e) {
+                // 如果转换失败，记录警告日志，并设置全局唯一标识符为null
+                Log.w(TAG, "failed to get related gid");
+                mRelatedGid = null;
+            }
+        }
+    }
+
+    // 从本地JSON对象设置内容，此方法不应该被调用
+    @Override
+    public void setContentByLocalJSON(JSONObject js) {
+        // 如果被调用，抛出异常
+        throw new IllegalAccessError("MetaData:setContentByLocalJSON should not be called");
+    }
+
+    // 从内容获取本地JSON对象，此方法不应该被调用
+    @Override
+    public JSONObject getLocalJSONFromContent() {
+        // 如果被调用，抛出异常
+        throw new IllegalAccessError("MetaData:getLocalJSONFromContent should not be called");
+    }
+
+    // 获取同步操作，此方法不应该被调用
+    @Override
+    public int getSyncAction(Cursor c) {
+        // 如果被调用，抛出异常
+        throw new IllegalAccessError("MetaData:getSyncAction should not be called");
+    }
+}

Node.java

@@ -0,0 +1,110 @@
+// 多行注释，说明版权信息和许可证
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的类
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+
+import org.json.JSONObject;
+
+// Node类是一个抽象类，用于表示任务或节点的数据结构
+public abstract class Node {
+    // 定义同步操作的常量
+    public static final int SYNC_ACTION_NONE = 0; // 无操作
+    public static final int SYNC_ACTION_ADD_REMOTE = 1; // 远程添加
+    public static final int SYNC_ACTION_ADD_LOCAL = 2; // 本地添加
+    public static final int SYNC_ACTION_DEL_REMOTE = 3; // 远程删除
+    public static final int SYNC_ACTION_DEL_LOCAL = 4; // 本地删除
+    public static final int SYNC_ACTION_UPDATE_REMOTE = 5; // 远程更新
+    public static final int SYNC_ACTION_UPDATE_LOCAL = 6; // 本地更新
+    public static final int SYNC_ACTION_UPDATE_CONFLICT = 7; // 更新冲突
+    public static final int SYNC_ACTION_ERROR = 8; // 错误
+
+    // 成员变量
+    private String mGid; // 节点的全局唯一标识符
+    private String mName; // 节点的名称
+    private long mLastModified; // 节点的最后修改时间
+    private boolean mDeleted; // 节点是否被删除
+
+    // 构造函数
+    public Node() {
+        mGid = null; // 初始时，全局唯一标识符为空
+        mName = ""; // 初始时，名称为空字符串
+        mLastModified = 0; // 初始时，最后修改时间为0
+        mDeleted = false; // 初始时，节点未被删除
+    }
+
+    // 获取创建操作的JSON对象
+    public abstract JSONObject getCreateAction(int actionId);
+
+    // 获取更新操作的JSON对象
+    public abstract JSONObject getUpdateAction(int actionId);
+
+    // 根据远程JSON对象设置内容
+    public abstract void setContentByRemoteJSON(JSONObject js);
+
+    // 根据本地JSON对象设置内容
+    public abstract void setContentByLocalJSON(JSONObject js);
+
+    // 从内容获取本地JSON对象
+    public abstract JSONObject getLocalJSONFromContent();
+
+    // 获取同步操作
+    public abstract int getSyncAction(Cursor c);
+
+    // 设置全局唯一标识符
+    public void setGid(String gid) {
+        this.mGid = gid;
+    }
+
+    // 设置节点名称
+    public void setName(String name) {
+        this.mName = name;
+    }
+
+    // 设置最后修改时间
+    public void setLastModified(long lastModified) {
+        this.mLastModified = lastModified;
+    }
+
+    // 设置节点是否被删除
+    public void setDeleted(boolean deleted) {
+        this.mDeleted = deleted;
+    }
+
+    // 获取全局唯一标识符
+    public String getGid() {
+        return this.mGid;
+    }
+
+    // 获取节点名称
+    public String getName() {
+        return this.mName;
+    }
+
+    // 获取最后修改时间
+    public long getLastModified() {
+        return this.mLastModified;
+    }
+
+    // 获取节点是否被删除
+    public boolean getDeleted() {
+        return this.mDeleted;
+    }
+
+}

Note.java

@@ -0,0 +1,248 @@
+// 包声明，定义了该类所在的包名
+package net.micode.notes.model;
+
+// 导入所需的Android类库
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderResult;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.OperationApplicationException;
+import android.net.Uri;
+import android.os.RemoteException;
+import android.util.Log;
+
+// 导入项目中定义的数据表和列名
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.Notes.TextNote;
+
+import java.util.ArrayList;
+
+// 定义Note类，用于表示一个便签
+public class Note {
+    // 用于存储便签数据的ContentValues对象
+    private ContentValues mNoteDiffValues;
+    // 用于存储便签数据的NoteData对象
+    private NoteData mNoteData;
+    // 定义日志标签
+    private static final String TAG = "Note";
+
+    /**
+     * 创建一个新的便签ID，用于将新的便签添加到数据库中
+     */
+    public static synchronized long getNewNoteId(Context context, long folderId) {
+        // 创建一个新的便签记录
+        ContentValues values = new ContentValues();
+        long createdTime = System.currentTimeMillis();
+        values.put(NoteColumns.CREATED_DATE, createdTime); // 设置创建时间
+        values.put(NoteColumns.MODIFIED_DATE, createdTime); // 设置修改时间
+        values.put(NoteColumns.TYPE, Notes.TYPE_NOTE); // 设置便签类型
+        values.put(NoteColumns.LOCAL_MODIFIED, 1); // 设置本地修改标志
+        values.put(NoteColumns.PARENT_ID, folderId); // 设置父ID，即文件夹ID
+        Uri uri = context.getContentResolver().insert(Notes.CONTENT_NOTE_URI, values); // 插入便签记录
+
+        long noteId = 0;
+        try {
+            noteId = Long.valueOf(uri.getPathSegments().get(1)); // 获取新创建的便签ID
+        } catch (NumberFormatException e) {
+            Log.e(TAG, "Get note id error :" + e.toString()); // 捕获异常并记录日志
+            noteId = 0;
+        }
+        if (noteId == -1) {
+            throw new IllegalStateException("Wrong note id:" + noteId); // 抛出异常
+        }
+        return noteId;
+    }
+
+    // Note类的构造函数
+    public Note() {
+        mNoteDiffValues = new ContentValues(); // 初始化ContentValues对象
+        mNoteData = new NoteData(); // 初始化NoteData对象
+    }
+
+    // 设置便签的值
+    public void setNoteValue(String key, String value) {
+        mNoteDiffValues.put(key, value); // 将键值对放入ContentValues
+        mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1); // 设置本地修改标志
+        mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis()); // 设置修改时间
+    }
+
+    // 设置文本数据
+    public void setTextData(String key, String value) {
+        mNoteData.setTextData(key, value); // 调用NoteData的方法设置文本数据
+    }
+
+    // 设置文本数据ID
+    public void setTextDataId(long id) {
+        mNoteData.setTextDataId(id); // 调用NoteData的方法设置文本数据ID
+    }
+
+    // 获取文本数据ID
+    public long getTextDataId() {
+        return mNoteData.mTextDataId; // 返回文本数据ID
+    }
+
+    // 设置通话数据ID
+    public void setCallDataId(long id) {
+        mNoteData.setCallDataId(id); // 调用NoteData的方法设置通话数据ID
+    }
+
+    // 设置通话数据
+    public void setCallData(String key, String value) {
+        mNoteData.setCallData(key, value); // 调用NoteData的方法设置通话数据
+    }
+
+    // 判断便签是否本地修改过
+    public boolean isLocalModified() {
+        return mNoteDiffValues.size() > 0 || mNoteData.isLocalModified(); // 返回是否修改过
+    }
+
+    // 同步便签数据
+    public boolean syncNote(Context context, long noteId) {
+        if (noteId <= 0) {
+            throw new IllegalArgumentException("Wrong note id:" + noteId); // 抛出异常
+        }
+
+        if (!isLocalModified()) {
+            return true; // 如果没有修改过，直接返回true
+        }
+
+        // 理论上，一旦数据发生变化，便签的LOCAL_MODIFIED和MODIFIED_DATE都应该更新
+        if (context.getContentResolver().update(
+                ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), mNoteDiffValues, null,
+                null) == 0) {
+            Log.e(TAG, "Update note error, should not happen"); // 记录日志
+            // Do not return, fall through
+        }
+        mNoteDiffValues.clear(); // 清空ContentValues
+
+        if (mNoteData.isLocalModified()
+                && (mNoteData.pushIntoContentResolver(context, noteId) == null)) {
+            return false; // 如果NoteData同步失败，返回false
+        }
+
+        return true; // 同步成功，返回true
+    }
+
+    // 定义NoteData内部类，用于存储便签的文本数据和通话数据
+    private class NoteData {
+        private long mTextDataId; // 文本数据ID
+        private ContentValues mTextDataValues; // 文本数据的ContentValues对象
+        private long mCallDataId; // 通话数据ID
+        private ContentValues mCallDataValues; // 通话数据的ContentValues对象
+        private static final String TAG = "NoteData"; // 日志标签
+
+        public NoteData() {
+            mTextDataValues = new ContentValues(); // 初始化文本数据的ContentValues对象
+            mCallDataValues = new ContentValues(); // 初始化通话数据的ContentValues对象
+            mTextDataId = 0; // 初始化文本数据ID
+            mCallDataId = 0; // 初始化通话数据ID
+        }
+
+        // 判断NoteData是否本地修改过
+        boolean isLocalModified() {
+            return mTextDataValues.size() > 0 || mCallDataValues.size() > 0; // 返回是否修改过
+        }
+
+        // 设置文本数据ID
+        void setTextDataId(long id) {
+            if(id <= 0) {
+                throw new IllegalArgumentException("Text data id should larger than 0"); // 抛出异常
+            }
+            mTextDataId = id; // 设置文本数据ID
+        }
+
+        // 设置通话数据ID
+        void setCallDataId(long id) {
+            if (id <= 0) {
+                throw new IllegalArgumentException("Call data id should larger than 0"); // 抛出异常
+            }
+            mCallDataId = id; // 设置通话数据ID
+        }
+
+        // 设置通话数据
+        void setCallData(String key, String value) {
+            mCallDataValues.put(key, value); // 将键值对放入通话数据的ContentValues
+            mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1); // 设置本地修改标志
+            mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis()); // 设置修改时间
+        }
+
+        // 设置文本数据
+        void setTextData(String key, String value) {
+            mTextDataValues.put(key, value); // 将键值对放入文本数据的ContentValues
+            mNoteDiffValues.put(NoteColumns.LOCAL_MODIFIED, 1); // 设置本地修改标志
+            mNoteDiffValues.put(NoteColumns.MODIFIED_DATE, System.currentTimeMillis()); // 设置修改时间
+        }
+
+        // 将NoteData的数据推送到ContentResolver
+        Uri pushIntoContentResolver(Context context, long noteId) {
+            if (noteId <= 0) {
+                throw new IllegalArgumentException("Wrong note id:" + noteId); // 抛出异常
+            }
+
+            ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>(); // 操作列表
+            ContentProviderOperation.Builder builder = null;
+
+            if(mTextDataValues.size() > 0) {
+                mTextDataValues.put(DataColumns.NOTE_ID, noteId); // 设置便签ID
+                if (mTextDataId == 0) {
+                    mTextDataValues.put(DataColumns.MIME_TYPE, TextNote.CONTENT_ITEM_TYPE); // 设置MIME类型
+                    Uri uri = context.getContentResolver().insert(Notes.CONTENT_DATA_URI,
+                            mTextDataValues); // 插入文本数据
+                    try {
+                        setTextDataId(Long.valueOf(uri.getPathSegments().get(1))); // 获取并设置文本数据ID
+                    } catch (NumberFormatException e) {
+                        Log.e(TAG, "Insert new text data fail with noteId" + noteId); // 记录日志
+                        mTextDataValues.clear(); // 清空ContentValues
+                        return null;
+                    }
+                } else {
+                    builder = ContentProviderOperation.newUpdate(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mTextDataId)); // 创建更新操作
+                    builder.withValues(mTextDataValues); // 设置更新的值
+                    operationList.add(builder.build()); // 添加到操作列表
+                }
+                mTextDataValues.clear(); // 清空ContentValues
+}
+	        if(mCallDataValues.size() > 0) {
+            mCallDataValues.put(DataColumns.NOTE_ID, noteId); // 设置便签ID
+            if (mCallDataId == 0) {
+                mCallDataValues.put(DataColumns.MIME_TYPE, CallNote.CONTENT_ITEM_TYPE); // 设置MIME类型
+                Uri uri = context.getContentResolver().insert(Notes.CONTENT_DATA_URI,
+                        mCallDataValues); // 插入通话数据
+                try {
+                    setCallDataId(Long.valueOf(uri.getPathSegments().get(1))); // 获取并设置通话数据ID
+                } catch (NumberFormatException e) {
+                    Log.e(TAG, "Insert new call data fail with noteId" + noteId); // 记录日志
+                    mCallDataValues.clear(); // 清空ContentValues
+                    return null;
+                }
+            } else {
+                builder = ContentProviderOperation.newUpdate(ContentUris.withAppendedId(
+                        Notes.CONTENT_DATA_URI, mCallDataId)); // 创建更新操作
+                builder.withValues(mCallDataValues); // 设置更新的值
+                operationList.add(builder.build()); // 添加到操作列表
+            }
+            mCallDataValues.clear(); // 清空ContentValues
+        }
+
+        if (operationList.size() > 0) {
+            try {
+                ContentProviderResult[] results = context.getContentResolver().applyBatch(
+                        Notes.AUTHORITY, operationList); // 批量执行操作
+                return (results == null || results.length == 0 || results[0] == null) ? null
+                        : ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId); // 返回更新后的URI
+            } catch (RemoteException e) {
+                Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage())); // 记录日志
+                return null;
+            } catch (OperationApplicationException e) {
+                Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage())); // 记录日志
+                return null;
+            }
+        }
+        return null;
+    }
+}

Notes.java

@@ -0,0 +1,256 @@
+package net.micode.notes.data; // 定义包名，表示这个类属于net.micode.notes.data包。
+
+import android.net.Uri; // 导入Android的Uri类，用于处理URI。
+
+public class Notes {
+    // 定义一些常量，用于应用程序的不同部分。
+    public static final String AUTHORITY = "micode_notes"; // 定义authority，用于URI的构建。
+    public static final String TAG = "Notes"; // 定义日志标签。
+    public static final int TYPE_NOTE = 0; // 笔记类型。
+    public static final int TYPE_FOLDER = 1; // 文件夹类型。
+    public static final int TYPE_SYSTEM = 2; // 系统类型。
+
+    // 定义系统文件夹的ID。
+    /**
+     * Following IDs are system folders' identifiers
+     * {@link Notes#ID_ROOT_FOLDER } is default folder
+     * {@link Notes#ID_TEMPARAY_FOLDER } is for notes belonging no folder
+     * {@link Notes#ID_CALL_RECORD_FOLDER} is to store call records
+     */
+    public static final int ID_ROOT_FOLDER = 0; // 根文件夹的ID。
+    public static final int ID_TEMPARAY_FOLDER = -1; // 临时文件夹的ID。
+    public static final int ID_CALL_RECORD_FOLDER = -2; // 通话记录文件夹的ID。
+    public static final int ID_TRASH_FOLER = -3; // 回收站文件夹的ID（注意：这里有个拼写错误，应该是FOLDER）。
+
+    // 定义Intent的额外数据键，用于在Activity之间传递数据。
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date"; // 闹钟日期。
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id"; // 背景颜色ID。
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id"; // 小部件ID。
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type"; // 小部件类型。
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id"; // 文件夹ID。
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date"; // 通话日期。
+
+    // 定义小部件类型的常量。
+    public static final int TYPE_WIDGET_INVALIDE = -1; // 无效的小部件类型。
+    public static final int TYPE_WIDGET_2X = 0; // 2x小部件类型。
+    public static final int TYPE_WIDGET_4X = 1; // 4x小部件类型。
+
+    public static class DataConstants {
+        // 定义数据常量类，包含笔记和通话记录的MIME类型。
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE; // 文本笔记的内容项类型。
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE; // 通话笔记的内容项类型。
+    }
+
+    // 定义用于查询所有笔记和文件夹的Uri。
+    /**
+     * Uri to query all notes and folders
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+    // 定义用于查询数据的Uri。
+    /**
+     * Uri to query data
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    // 定义NoteColumns接口，包含笔记或文件夹的列。
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id"; // 行的唯一ID。
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id"; // 父ID。
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date"; // 创建日期。
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date"; // 最后修改日期。
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date"; // 提醒日期。
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet"; // 片段，文件夹的名称或笔记的文本内容。
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id"; // 小部件ID。
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type"; // 小部件类型。
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String BG_COLOR_ID = "bg_color_id"; // 背景颜色ID。
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment"; // 是否有附件。
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count"; // 文件夹中的笔记数量。
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type"; // 文件类型：文件夹或笔记。
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id"; // 最后同步ID。
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified"; // 是否本地修改。
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id"; // 移动到临时文件夹之前的原始父ID。
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id"; // gtask ID。
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version"; // 版本号。
+    }
+
+    // 定义DataColumns接口，包含数据的列。
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id"; // 行的唯一ID。
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type"; // 项目的MIME类型。
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id"; // 笔记ID。
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date"; // 创建日期。
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date"; // 最后修改日期。
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content"; // 数据内容。
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1"; // 用于整数数据类型的通用数据列。
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2"; // 同上。
+             /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3"; // 用于文本数据类型的通用数据列。
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4"; // 同上。
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA5 = "data5"; // 同上。
+    }
+
+    // 定义TextNote类，实现DataColumns接口，用于文本笔记。
+    public static final class TextNote implements DataColumns {
+        /**
+         * Mode to indicate the text in check list mode or not
+         * <P> Type: Integer 1:check list mode 0: normal mode </P>
+         */
+        public static final String MODE = DATA1; // 模式，用于检查列表模式或普通模式。
+        public static final int MODE_CHECK_LIST = 1; // 检查列表模式。
+        /**
+         * MIME type for a directory of text notes
+         */
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note"; // 文本笔记的目录MIME类型。
+        /**
+         * MIME type for a single text note
+         */
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note"; // 单个文本笔记的MIME类型。
+        /**
+         * The content URI for text notes
+         */
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note"); // 文本笔记的内容URI。
+    }
+
+    // 定义CallNote类，实现DataColumns接口，用于通话记录笔记。
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CALL_DATE = DATA1; // 通话日期。
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+        public static final String PHONE_NUMBER = DATA3; // 电话号码。
+        /**
+         * MIME type for a directory of call notes
+         */
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note"; // 通话记录的目录MIME类型。
+        /**
+         * MIME type for a single call note
+         */
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note"; // 单个通话记录的MIME类型。
+        /**
+         * The content URI for call notes
+         */
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note"); // 通话记录的内容URI。
+    }
+}

NotesDatabaseHelper.java

@@ -0,0 +1,349 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// 包和类的导入
+package net.micode.notes.data;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.util.Log;
+
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+
+// 数据库帮助类
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // 数据库名称
+    private static final String DB_NAME = "note.db";
+    // 数据库版本
+    private static final int DB_VERSION = 4;
+
+    // 表名常量接口
+    public interface TABLE {
+        public static final String NOTE = "note";
+        public static final String DATA = "data";
+    }
+
+    // 标签常量，用于日志输出
+    private static final String TAG = "NotesDatabaseHelper";
+    // 单例实例
+    private static NotesDatabaseHelper mInstance;
+
+    // 创建笔记表的SQL语句
+    private static final String CREATE_NOTE_TABLE_SQL =
+        "CREATE TABLE " + TABLE.NOTE + "(" +
+            NoteColumns.ID + " INTEGER PRIMARY KEY," +
+            NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
+            NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
+            NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
+        ")";
+
+    // 创建数据表的SQL语句
+    private static final String CREATE_DATA_TABLE_SQL =
+        "CREATE TABLE " + TABLE.DATA + "(" +
+            DataColumns.ID + " INTEGER PRIMARY KEY," +
+            DataColumns.MIME_TYPE + " TEXT NOT NULL," +
+            DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA1 + " INTEGER," +
+            DataColumns.DATA2 + " INTEGER," +
+            DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
+            DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
+        ")";
+
+    // 创建数据表中笔记ID索引的SQL语句
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    // 更新文件夹笔记数量的触发器SQL语句（当移动笔记时）
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_update "+
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    // 减少文件夹笔记数量的触发器SQL语句（当从文件夹中移除笔记时）
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_update " +
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+        " END";
+
+    // 插入新笔记时增加文件夹笔记数量的触发器SQL语句
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_insert " +
+        " AFTER INSERT ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    // 从文件夹中删除笔记时减少文件夹笔记数量的触发器SQL语句
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+        " END";
+
+    // 插入数据时更新笔记内容的触发器SQL语句
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_insert " +
+        " AFTER INSERT ON " + TABLE.DATA +
+        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    // 更新数据时更新笔记内容的触发器SQL语句
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_update " +
+        " AFTER UPDATE ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    // 删除数据时更新笔记内容的触发器SQL语句
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_delete " +
+        " AFTER delete ON " + TABLE.DATA +
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=''" +
+        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    // 删除笔记时删除属于该笔记的数据的触发器SQL语句
+    private static final String NOTE_DELETE_DATA_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER delete_data_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN" +
+        "  DELETE FROM " + TABLE.DATA +    "   WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" +
+    " END";
+
+// 删除文件夹时删除属于该文件夹的笔记的触发器SQL语句
+private static final String FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER =
+    "CREATE TRIGGER folder_delete_notes_on_delete " +
+    " AFTER DELETE ON " + TABLE.NOTE +
+    " BEGIN" +
+    "  DELETE FROM " + TABLE.NOTE +
+    "   WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+    " END";
+
+// 将笔记移动到回收站文件夹时移动属于该文件夹的笔记的触发器SQL语句
+private static final String FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER =
+    "CREATE TRIGGER folder_move_notes_on_trash " +
+    " AFTER UPDATE ON " + TABLE.NOTE +
+    " WHEN new." + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+    " BEGIN" +
+    "  UPDATE " + TABLE.NOTE +
+    "   SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER +
+    "  WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" +
+    " END";
+
+// 构造函数
+public NotesDatabaseHelper(Context context) {
+    super(context, DB_NAME, null, DB_VERSION);
+}
+
+// 创建笔记表的方法
+public void createNoteTable(SQLiteDatabase db) {
+    db.execSQL(CREATE_NOTE_TABLE_SQL);
+    reCreateNoteTableTriggers(db);
+    createSystemFolder(db);
+    Log.d(TAG, "note table has been created");
+}
+
+// 重新创建笔记表触发器的方法
+private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+    db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
+    db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
+    db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete");
+    db.execSQL("DROP TRIGGER IF EXISTS delete_data_on_delete");
+    db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
+    db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
+    db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
+
+    db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+    db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+    db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
+    db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
+    db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
+    db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
+    db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
+}
+
+// 创建系统文件夹的方法
+private void createSystemFolder(SQLiteDatabase db) {
+    ContentValues values = new ContentValues();
+
+    // 创建通话记录文件夹
+    values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+
+    // 创建根文件夹（默认文件夹）
+    values.clear();
+    values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+
+    // 创建临时文件夹（用于移动笔记）
+    values.clear();
+    values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+
+    // 创建回收站文件夹
+    values.clear();
+    values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+}
+
+// 创建数据表的方法
+public void createDataTable(SQLiteDatabase db) {
+    db.execSQL(CREATE_DATA_TABLE_SQL);
+    reCreateDataTableTriggers(db);
+    db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
+    Log.d(TAG, "data table has been created");
+}
+
+// 重新创建数据表触发器的方法
+private void reCreateDataTableTriggers(SQLiteDatabase db) {
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert");
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_update");
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_delete");
+
+    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER);
+    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER);
+    db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER);
+}
+
+// 获取单例实例的方法
+static synchronized NotesDatabaseHelper getInstance(Context context) {
+    if (mInstance == null) {
+        mInstance = new NotesDatabaseHelper(context);
+    }
+    return mInstance;
+}
+
+// 当创建数据库时调用的方法
+@Override
+public void onCreate(SQLiteDatabase db) {
+    createNoteTable(db);
+    createDataTable(db);
+}
+
+// 当数据库升级时调用的方法
+@Override
+public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+    boolean reCreateTriggers = false;
+    boolean skipV2 = false;
+
+    if (oldVersion == 1) {
+        upgradeToV2(db);
+        skipV2 = true; // this upgrade including the upgrade from v2 to v3
+        oldVersion++;
+    }
+
+    if (oldVersion == 2 && !skipV2) {
+        upgradeToV3(db);
+        reCreateTriggers = true;
+        oldVersion++;
+    }
+
+    if (oldVersion == 3) {
+        upgradeToV4(db);
+        oldVersion++;
+    }
+
+    if (reCreateTriggers) {
+        reCreateNoteTableTriggers(db);
+        reCreateDataTableTriggers(db);
+    }
+
+    if (oldVersion != newVersion) {
+        throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                + "fails");
+    }
+}
+
+// 升级到版本2的方法
+private void upgradeToV2(SQLiteDatabase db) {
+    db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
+    db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
+    createNoteTable(db);
+    createDataTable(db);
+}
+
+// 升级到版本3的方法
+private void upgradeToV3(SQLiteDatabase db) {
+    // 删除未使用的触发器
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+    db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+    // 添加gtask id列
+    db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+            + " TEXT NOT NULL DEFAULT ''");
+    // 添加回收站系统文件夹
+    ContentValues values = new ContentValues();
+    values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+    values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+    db.insert(TABLE.NOTE, null, values);
+}
+
+// 升级到版本4的方法
+private void upgradeToV4(SQLiteDatabase db) {
+    db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+            + " INTEGER NOT NULL DEFAULT 0");
+}

NotesProvider.java

@@ -0,0 +1,305 @@
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.app.SearchManager;
+import android.content.ContentProvider;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Intent;
+import android.content.UriMatcher;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.net.Uri;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+
+// 主要的 NotesProvider 类，继承自 ContentProvider
+public class NotesProvider extends ContentProvider {
+    private static final UriMatcher mMatcher; // URI匹配器
+
+    private NotesDatabaseHelper mHelper; // 数据库帮助类
+
+    private static final String TAG = "NotesProvider"; // 日志标签
+
+    // 定义URI匹配码
+    private static final int URI_NOTE            = 1;
+    private static final int URI_NOTE_ITEM       = 2;
+    private static final int URI_DATA            = 3;
+    private static final int URI_DATA_ITEM       = 4;
+
+    private static final int URI_SEARCH          = 5;
+    private static final int URI_SEARCH_SUGGEST  = 6;
+
+    // 初始化URI匹配器
+    static {
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
+    }
+
+    // 定义搜索时使用的投影
+    /**
+     * x'0A' represents the '\n' character in sqlite. For title and content in the search result,
+     * we will trim '\n' and white space in order to show more information.
+     */
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+
+    // 定义搜索查询
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+        + " FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    public boolean onCreate() {
+        mHelper = NotesDatabaseHelper.getInstance(getContext()); // 获取数据库帮助类的实例
+        return true;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+            String sortOrder) {
+        Cursor c = null;
+        SQLiteDatabase db = mHelper.getReadableDatabase(); // 获取可读数据库
+        String id = null;
+        switch (mMatcher.match(uri)) { // 匹配URI
+            case URI_NOTE:
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1); // 获取路径中的ID
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1); // 获取路径中的ID
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_SEARCH:
+            case URI_SEARCH_SUGGEST:
+                if (sortOrder != null || projection != null) {
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
+                }
+
+                String searchString = null;
+                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
+                    if (uri.getPathSegments().size() > 1) {
+                        searchString = uri.getPathSegments().get(1);
+                    }
+                } else {
+                    searchString = uri.getQueryParameter("pattern");
+                }
+
+                if (TextUtils.isEmpty(searchString)) {
+                    return null;
+                }
+
+                try {
+                    searchString = String.format("%%%s%%", searchString);
+                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
+                            new String[] { searchString });
+                } catch (IllegalStateException ex) {
+                    Log.e(TAG, "got exception: " + ex.toString());
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri); // 设置通知URI
+        }
+        return c;
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        SQLiteDatabase db = mHelper.getWritableDatabase(); // 获取可写数据库
+        long dataId = 0, noteId = 0, insertedId = 0;
+        switch (mMatcher.match(uri)) { // 匹配URI
+            case URI_NOTE:
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values); // 插入笔记
+                break;
+            case URI_DATA:
+                if (values.containsKey(DataColumns.NOTE_ID)) {
+                    noteId = values.getAsLong(DataColumns.NOTE_ID); // 获取笔记ID
+                } else {
+                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
+                }
+                insertedId = dataId = db.insert(TABLE.DATA, null, values); // 插入数据
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // Notify the note uri
+        if (noteId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
+        }
+
+        // Notify the data uri
+        if (dataId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
+        }
+
+        return ContentUris.withAppendedId(uri, insertedId); // 返回插入的URI
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        int count = 0;
+        String id = null;
+        SQLiteDatabase db = mHelper.getWritableDatabase(); // 获取可写数据库
+        boolean deleteData = false;
+        switch (mMatcher.match(uri)) { // 匹配URI
+            case URI_NOTE:
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 "; // 确保ID大于0
+                count = db.delete(TABLE.NOTE, selection, selectionArgs); // 删除笔记
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1); // 获取路径中的ID
+                /**
+                 * ID that smaller than 0 is system folder which is not allowed to
+                 * trash
+                 */
+                long noteId = Long.valueOf(id);
+                if (noteId <= 0) {
+                    break;
+                }
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" +id + parseSelection(selection), selectionArgs); // 删除笔记项
+					break;
+			case URI_DATA:
+				count = db.delete(TABLE.DATA, selection, selectionArgs); // 删除数据
+				deleteData = true;
+					break;
+			case URI_DATA_ITEM:
+				id = uri.getPathSegments().get(1); // 获取路径中的ID
+				count = db.delete(TABLE.DATA,
+				DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs); // 删除数据项
+				deleteData = true;
+				break;
+			default:
+				throw new IllegalArgumentException("Unknown URI " + uri);
+		}
+	if (count > 0) {
+		if (deleteData) {
+			getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null); // 通知删除数据
+		}
+		getContext().getContentResolver().notifyChange(uri, null); // 通知删除
+	}		
+	return count;
+}
+@Override
+public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+    int count = 0;
+    String id = null;
+    SQLiteDatabase db = mHelper.getWritableDatabase(); // 获取可写数据库
+    boolean updateData = false;
+    switch (mMatcher.match(uri)) { // 匹配URI
+        case URI_NOTE:
+            increaseNoteVersion(-1, selection, selectionArgs); // 增加笔记版本
+            count = db.update(TABLE.NOTE, values, selection, selectionArgs); // 更新笔记
+            break;
+        case URI_NOTE_ITEM:
+            id = uri.getPathSegments().get(1); // 获取路径中的ID
+            increaseNoteVersion(Long.valueOf(id), selection, selectionArgs); // 增加笔记版本
+            count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                    + parseSelection(selection), selectionArgs); // 更新笔记项
+            break;
+        case URI_DATA:
+            count = db.update(TABLE.DATA, values, selection, selectionArgs); // 更新数据
+            updateData = true;
+            break;
+        case URI_DATA_ITEM:
+            id = uri.getPathSegments().get(1); // 获取路径中的ID
+            count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                    + parseSelection(selection), selectionArgs); // 更新数据项
+            updateData = true;
+            break;
+        default:
+            throw new IllegalArgumentException("Unknown URI " + uri);
+    }
+
+    if (count > 0) {
+        if (updateData) {
+            getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null); // 通知更新数据
+        }
+        getContext().getContentResolver().notifyChange(uri, null); // 通知更新
+    }
+    return count;
+}
+
+private String parseSelection(String selection) {
+    return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""); // 解析选择条件
+}
+
+private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+    StringBuilder sql = new StringBuilder(120);
+    sql.append("UPDATE ");
+    sql.append(TABLE.NOTE);
+    sql.append(" SET ");
+    sql.append(NoteColumns.VERSION);
+    sql.append("=" + NoteColumns.VERSION + "+1 ");
+
+    if (id > 0 || !TextUtils.isEmpty(selection)) {
+        sql.append(" WHERE ");
+    }
+    if (id > 0) {
+        sql.append(NoteColumns.ID + "=" + String.valueOf(id));
+    }
+    if (!TextUtils.isEmpty(selection)) {
+        String selectString = id > 0 ? parseSelection(selection) : selection;
+        for (String args : selectionArgs) {
+            selectString = selectString.replaceFirst("\\?", args);
+        }
+        sql.append(selectString);
+    }
+
+    mHelper.getWritableDatabase().execSQL(sql.toString()); // 执行更新SQL
+}
+
+@Override
+public String getType(Uri uri) {
+    // TODO Auto-generated method stub
+    return null;
+}

SqlData.java

@@ -0,0 +1,191 @@
+// 多行注释，说明版权信息和许可证
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的类
+package net.micode.notes.gtask.data;
+
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.NotesDatabaseHelper.TABLE;
+import net.micode.notes.gtask.exception.ActionFailureException;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+// SqlData类用于处理与数据库相关的操作
+public class SqlData {
+    // 类的标签，用于日志记录
+    private static final String TAG = SqlData.class.getSimpleName();
+
+    // 定义一个无效的ID值
+    private static final int INVALID_ID = -99999;
+
+    // 数据库查询的列
+    public static final String[] PROJECTION_DATA = new String[] {
+            DataColumns.ID, DataColumns.MIME_TYPE, DataColumns.CONTENT, DataColumns.DATA1,
+            DataColumns.DATA3
+    };
+
+    // 定义查询列的索引
+    public static final int DATA_ID_COLUMN = 0;
+    public static final int DATA_MIME_TYPE_COLUMN = 1;
+    public static final int DATA_CONTENT_COLUMN = 2;
+    public static final int DATA_CONTENT_DATA_1_COLUMN = 3;
+    public static final int DATA_CONTENT_DATA_3_COLUMN = 4;
+
+    // 成员变量
+    private ContentResolver mContentResolver; // 内容解析器
+    private boolean mIsCreate; // 是否为创建操作
+    private long mDataId; // 数据ID
+    private String mDataMimeType; // 数据MIME类型
+    private String mDataContent; // 数据内容
+    private long mDataContentData1; // 数据内容的DATA1字段
+    private String mDataContentData3; // 数据内容的DATA3字段
+    private ContentValues mDiffDataValues; // 与数据库不同的数据内容
+
+    // 构造函数，用于创建新的SqlData对象
+    public SqlData(Context context) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mDataId = INVALID_ID;
+        mDataMimeType = DataConstants.NOTE;
+        mDataContent = "";
+        mDataContentData1 = 0;
+        mDataContentData3 = "";
+        mDiffDataValues = new ContentValues();
+    }
+
+    // 构造函数，用于从数据库中加载现有的SqlData对象
+    public SqlData(Context context, Cursor c) {
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDiffDataValues = new ContentValues();
+    }
+
+    // 从游标加载数据
+    private void loadFromCursor(Cursor c) {
+        mDataId = c.getLong(DATA_ID_COLUMN);
+        mDataMimeType = c.getString(DATA_MIME_TYPE_COLUMN);
+        mDataContent = c.getString(DATA_CONTENT_COLUMN);
+        mDataContentData1 = c.getLong(DATA_CONTENT_DATA_1_COLUMN);
+        mDataContentData3 = c.getString(DATA_CONTENT_DATA_3_COLUMN);
+    }
+
+    // 设置内容，从JSONObject中读取数据
+    public void setContent(JSONObject js) throws JSONException {
+        long dataId = js.has(DataColumns.ID) ? js.getLong(DataColumns.ID) : INVALID_ID;
+        if (mIsCreate || mDataId != dataId) {
+            mDiffDataValues.put(DataColumns.ID, dataId);
+        }
+        mDataId = dataId;
+
+        String dataMimeType = js.has(DataColumns.MIME_TYPE) ? js.getString(DataColumns.MIME_TYPE)
+                : DataConstants.NOTE;
+        if (mIsCreate || !mDataMimeType.equals(dataMimeType)) {
+            mDiffDataValues.put(DataColumns.MIME_TYPE, dataMimeType);
+        }
+        mDataMimeType = dataMimeType;
+
+        String dataContent = js.has(DataColumns.CONTENT) ? js.getString(DataColumns.CONTENT) : "";
+        if (mIsCreate || !mDataContent.equals(dataContent)) {
+            mDiffDataValues.put(DataColumns.CONTENT, dataContent);
+        }
+        mDataContent = dataContent;
+
+        long dataContentData1 = js.has(DataColumns.DATA1) ? js.getLong(DataColumns.DATA1) : 0;
+        if (mIsCreate || mDataContentData1 != dataContentData1) {
+            mDiffDataValues.put(DataColumns.DATA1, dataContentData1);
+        }
+        mDataContentData1 = dataContentData1;
+
+        String dataContentData3 = js.has(DataColumns.DATA3) ? js.getString(DataColumns.DATA3) : "";
+        if (mIsCreate || !mDataContentData3.equals(dataContentData3)) {
+            mDiffDataValues.put(DataColumns.DATA3, dataContentData3);
+        }
+        mDataContentData3 = dataContentData3;
+    }
+
+    // 获取内容，返回JSONObject
+    public JSONObject getContent() throws JSONException {
+        if (mIsCreate) {
+            Log.e(TAG, "it seems that we haven't created this in database yet");
+            return null;
+        }
+        JSONObject js = new JSONObject();
+        js.put(DataColumns.ID, mDataId);
+        js.put(DataColumns.MIME_TYPE, mDataMimeType);
+        js.put(DataColumns.CONTENT, mDataContent);
+        js.put(DataColumns.DATA1, mDataContentData1);
+        js.put(DataColumns.DATA3, mDataContentData3);
+        return js;
+    }
+
+    // 提交数据到数据库
+    public void commit(long noteId, boolean validateVersion, long version) {
+        if (mIsCreate) {
+            if (mDataId == INVALID_ID && mDiffDataValues.containsKey(DataColumns.ID)) {
+                mDiffDataValues.remove(DataColumns.ID);
+            }
+
+            mDiffDataValues.put(DataColumns.NOTE_ID, noteId);
+            Uri uri = mContentResolver.insert(Notes.CONTENT_DATA_URI, mDiffDataValues);
+            try {
+                mDataId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+        } else {
+            if (mDiffDataValues.size() > 0) {
+                int result = 0;
+                if (!validateVersion) {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues, null, null);
+                } else {
+                    result = mContentResolver.update(ContentUris.withAppendedId(
+                            Notes.CONTENT_DATA_URI, mDataId), mDiffDataValues,
+                            " ? in (SELECT " + NoteColumns.ID + " FROM " + TABLE.NOTE
+                                    + " WHERE " + NoteColumns.VERSION + "=?)", new String[] {
+                                    String.valueOf(noteId), String.valueOf(version)
+                            });
+                }
+                if (result == 0) {
+                    Log.w(TAG, "there is no update. maybe user updates note when syncing");
+                }
+            }
+        }
+
+        mDiffDataValues.clear();
+        mIsCreate = false;
+    }
+
+    // 获取数据ID
+    public long getId() {
+        return mDataId;
+    }
+}

SqlNote.java

@@ -0,0 +1,483 @@
+// 多行注释，说明版权信息和许可证
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的类
+package net.micode.notes.gtask.data;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+import net.micode.notes.tool.ResourceParser;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+// SqlNote类用于处理与数据库相关的笔记操作
+public class SqlNote {
+    // 类的标签，用于日志记录
+    private static final String TAG = SqlNote.class.getSimpleName();
+
+    // 定义一个无效的ID值
+    private static final int INVALID_ID = -99999;
+
+    // 数据库查询的列
+    public static final String[] PROJECTION_NOTE = new String[] {
+            NoteColumns.ID, NoteColumns.ALERTED_DATE, NoteColumns.BG_COLOR_ID,
+            NoteColumns.CREATED_DATE, NoteColumns.HAS_ATTACHMENT, NoteColumns.MODIFIED_DATE,
+            NoteColumns.NOTES_COUNT, NoteColumns.PARENT_ID, NoteColumns.SNIPPET, NoteColumns.TYPE,
+            NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE, NoteColumns.SYNC_ID,
+            NoteColumns.LOCAL_MODIFIED, NoteColumns.ORIGIN_PARENT_ID, NoteColumns.GTASK_ID,
+            NoteColumns.VERSION
+    };
+
+    // 定义查询列的索引
+    public static final int ID_COLUMN = 0;
+    public static final int ALERTED_DATE_COLUMN = 1;
+    public static final int BG_COLOR_ID_COLUMN = 2;
+    public static final int CREATED_DATE_COLUMN = 3;
+    public static final int HAS_ATTACHMENT_COLUMN = 4;
+    public static final int MODIFIED_DATE_COLUMN = 5;
+    public static final int NOTES_COUNT_COLUMN = 6;
+    public static final int PARENT_ID_COLUMN = 7;
+    public static final int SNIPPET_COLUMN = 8;
+    public static final int TYPE_COLUMN = 9;
+    public static final int WIDGET_ID_COLUMN = 10;
+    public static final int WIDGET_TYPE_COLUMN = 11;
+    public static final int SYNC_ID_COLUMN = 12;
+    public static final int LOCAL_MODIFIED_COLUMN = 13;
+    public static final int ORIGIN_PARENT_ID_COLUMN = 14;
+    public static final int GTASK_ID_COLUMN = 15;
+    public static final int VERSION_COLUMN = 16;
+
+    // 成员变量
+    private Context mContext; // 上下文
+    private ContentResolver mContentResolver; // 内容解析器
+    private boolean mIsCreate; // 是否为创建操作
+    private long mId; // 笔记ID
+    private long mAlertDate; // 提醒日期
+    private int mBgColorId; // 背景颜色ID
+    private long mCreatedDate; // 创建日期
+    private int mHasAttachment; // 是否有附件
+    private long mModifiedDate; // 修改日期
+    private long mParentId; // 父笔记ID
+    private String mSnippet; // 笔记摘要
+    private int mType; // 笔记类型
+    private int mWidgetId; // 小部件ID
+    private int mWidgetType; // 小部件类型
+    private long mOriginParent; // 原始父笔记ID
+    private long mVersion; // 版本号
+    private ContentValues mDiffNoteValues; // 与数据库不同的笔记内容
+    private ArrayList<SqlData> mDataList; // 数据列表
+
+    // 构造函数，用于创建新的SqlNote对象
+    public SqlNote(Context context) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = true;
+        mId = INVALID_ID;
+        mAlertDate = 0;
+        mBgColorId = ResourceParser.getDefaultBgId(context);
+        mCreatedDate = System.currentTimeMillis();
+        mHasAttachment = 0;
+        mModifiedDate = System.currentTimeMillis();
+        mParentId = 0;
+        mSnippet = "";
+        mType = Notes.TYPE_NOTE;
+        mWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+        mOriginParent = 0;
+        mVersion = 0;
+        mDiffNoteValues = new ContentValues();
+        mDataList = new ArrayList<SqlData>();
+    }
+
+    // 构造函数，用于从数据库中加载现有的SqlNote对象
+    public SqlNote(Context context, Cursor c) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(c);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+    }
+
+    // 构造函数，用于从数据库中加载特定的SqlNote对象
+    public SqlNote(Context context, long id) {
+        mContext = context;
+        mContentResolver = context.getContentResolver();
+        mIsCreate = false;
+        loadFromCursor(id);
+        mDataList = new ArrayList<SqlData>();
+        if (mType == Notes.TYPE_NOTE)
+            loadDataContent();
+        mDiffNoteValues = new ContentValues();
+    }
+
+    // 从游标加载数据
+    private void loadFromCursor(long id) {
+        Cursor c = null;
+        try {
+            c = mContentResolver.query(Notes.CONTENT_NOTE_URI, PROJECTION_NOTE, "(_id=?)",
+                    new String[] {
+                        String.valueOf(id)
+                    }, null);
+            if (c != null) {
+                c.moveToNext();
+                loadFromCursor(c);
+            } else {
+                Log.w(TAG, "loadFromCursor: cursor = null");
+            }
+        } finally {
+            if (c != null)
+                c.close();
+        }
+    }
+
+    // 从游标加载数据
+    private void loadFromCursor(Cursor c) {
+        mId = c.getLong(ID_COLUMN);
+        mAlertDate = c.getLong(ALERTED_DATE_COLUMN);
+        mBgColorId = c.getInt(BG_COLOR_ID_COLUMN);
+        mCreatedDate = c.getLong(CREATED_DATE_COLUMN);
+        mHasAttachment = c.getInt(HAS_ATTACHMENT_COLUMN);
+        mModifiedDate = c.getLong(MODIFIED_DATE_COLUMN);
+        mParentId = c.getLong(PARENT_ID_COLUMN);
+        mSnippet = c.getString(SNIPPET_COLUMN);
+        mType = c.getInt(TYPE_COLUMN);
+        mWidgetId = c.getInt(WIDGET_ID_COLUMN);
+        mWidgetType = c.getInt(WIDGET_TYPE_COLUMN);
+        mVersion = c.getLong(VERSION_COLUMN);
+    }
+
+    // 加载数据内容
+    private void loadDataContent() {
+        Cursor c = null;
+        mDataList.clear();
+        try {
+            c = mContentResolver.query(Notes.CONTENT_DATA_URI, SqlData.PROJECTION_DATA,
+                    "(note_id=?)", new String[] {
+                        String.valueOf(mId)
+                    }, null);
+            if (c != null) {
+                if (c.getCount() == 0) {
+                    Log.w(TAG, "it seems that the note has not data");
+                    return;
+                }
+                while (c.moveToNext()) {
+                    SqlData data = new SqlData(mContext, c);
+                    mDataList.add(data);
+                }
+            } else {
+                Log.w(TAG, "loadDataContent: cursor = null");
+            }
+        } finally {
+            if (c != null)
+
+        }
+    }
+
+    // 设置内容，从JSONObject中读取数据
+    public boolean setContent(JSONObject js) {
+        try {
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                Log.w(TAG, "cannot set system folder");
+                return false;
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                // for folder we can only update the snnipet and type
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+            } else if (note.getInt(NoteColumns.TYPE) == Notes.TYPE_NOTE) {
+                JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+                long id = note.has(NoteColumns.ID) ? note.getLong(NoteColumns.ID) : INVALID_ID;
+                if (mIsCreate || mId != id) {
+                    mDiffNoteValues.put(NoteColumns.ID, id);
+                }
+                mId = id;
+
+                long alertDate = note.has(NoteColumns.ALERTED_DATE) ? note
+                        .getLong(NoteColumns.ALERTED_DATE) : 0;
+                if (mIsCreate || mAlertDate != alertDate) {
+                    mDiffNoteValues.put(NoteColumns.ALERTED_DATE, alertDate);
+                }
+                mAlertDate = alertDate;
+
+                int bgColorId = note.has(NoteColumns.BG_COLOR_ID) ? note
+                        .getInt(NoteColumns.BG_COLOR_ID) : ResourceParser.getDefaultBgId(mContext);
+                if (mIsCreate || mBgColorId != bgColorId) {
+                    mDiffNoteValues.put(NoteColumns.BG_COLOR_ID, bgColorId);
+                }
+                mBgColorId = bgColorId;
+
+                long createDate = note.has(NoteColumns.CREATED_DATE) ? note
+                        .getLong(NoteColumns.CREATED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mCreatedDate != createDate) {
+                    mDiffNoteValues.put(NoteColumns.CREATED_DATE, createDate);
+                }
+                mCreatedDate = createDate;
+
+                int hasAttachment = note.has(NoteColumns.HAS_ATTACHMENT) ? note
+                        .getInt(NoteColumns.HAS_ATTACHMENT) : 0;
+                if (mIsCreate || mHasAttachment != hasAttachment) {
+                    mDiffNoteValues.put(NoteColumns.HAS_ATTACHMENT, hasAttachment);
+                }
+                mHasAttachment = hasAttachment;
+
+                long modifiedDate = note.has(NoteColumns.MODIFIED_DATE) ? note
+                        .getLong(NoteColumns.MODIFIED_DATE) : System.currentTimeMillis();
+                if (mIsCreate || mModifiedDate != modifiedDate) {
+                    mDiffNoteValues.put(NoteColumns.MODIFIED_DATE, modifiedDate);
+                }
+                mModifiedDate = modifiedDate;
+
+                long parentId = note.has(NoteColumns.PARENT_ID) ? note
+                        .getLong(NoteColumns.PARENT_ID) : 0;
+                if (mIsCreate || mParentId != parentId) {
+                    mDiffNoteValues.put(NoteColumns.PARENT_ID, parentId);
+                }
+                mParentId = parentId;
+
+                String snippet = note.has(NoteColumns.SNIPPET) ? note
+                        .getString(NoteColumns.SNIPPET) : "";
+                if (mIsCreate || !mSnippet.equals(snippet)) {
+                    mDiffNoteValues.put(NoteColumns.SNIPPET, snippet);
+                }
+                mSnippet = snippet;
+
+                int type = note.has(NoteColumns.TYPE) ? note.getInt(NoteColumns.TYPE)
+                        : Notes.TYPE_NOTE;
+                if (mIsCreate || mType != type) {
+                    mDiffNoteValues.put(NoteColumns.TYPE, type);
+                }
+                mType = type;
+
+                int widgetId = note.has(NoteColumns.WIDGET_ID) ? note.getInt(NoteColumns.WIDGET_ID)
+                        : AppWidgetManager.INVALID_APPWIDGET_ID;
+                if (mIsCreate || mWidgetId != widgetId) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_ID, widgetId);
+                }
+                mWidgetId = widgetId;
+
+                int widgetType = note.has(NoteColumns.WIDGET_TYPE) ? note
+                        .getInt(NoteColumns.WIDGET_TYPE) : Notes.TYPE_WIDGET_INVALIDE;
+                if (mIsCreate || mWidgetType != widgetType) {
+                    mDiffNoteValues.put(NoteColumns.WIDGET_TYPE, widgetType);
+                }
+                mWidgetType = widgetType;
+
+                long originParent = note.has(NoteColumns.ORIGIN_PARENT_ID) ? note
+                        .getLong(NoteColumns.ORIGIN_PARENT_ID) : 0;
+                if (mIsCreate || mOriginParent != originParent) {
+                    mDiffNoteValues.put(NoteColumns.ORIGIN_PARENT_ID, originParent);
+                }
+                mOriginParent = originParent;
+
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    SqlData sqlData = null;
+                    if (data.has(DataColumns.ID)) {
+                        long dataId = data.getLong(DataColumns.ID);
+                        for (SqlData temp : mDataList) {
+                            if (dataId == temp.getId()) {
+                                sqlData = temp;
+                            }
+                        }
+                    }
+
+                    if (sqlData == null) {
+                        sqlData = new SqlData(mContext);
+                        mDataList.add(sqlData);
+                    }
+
+                    sqlData.setContent(data);
+                }
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return false;
+        }
+        return true;
+    }
+
+    // 获取内容，返回JSONObject
+    public JSONObject getContent() {
+        try {
+            JSONObject js = new JSONObject();
+
+            if (mIsCreate) {
+                Log.e(TAG, "it seems that we haven't created this in database yet");
+                return null;
+            }
+
+            JSONObject note = new JSONObject();
+            if (mType == Notes.TYPE_NOTE) {
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.ALERTED_DATE, mAlertDate);
+                note.put(NoteColumns.BG_COLOR_ID, mBgColorId);
+                note.put(NoteColumns.CREATED_DATE, mCreatedDate);
+                note.put(NoteColumns.HAS_ATTACHMENT, mHasAttachment);
+                note.put(NoteColumns.MODIFIED_DATE, mModifiedDate);
+                note.put(NoteColumns.PARENT_ID, mParentId);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.WIDGET_ID, mWidgetId);
+                note.put(NoteColumns.WIDGET_TYPE, mWidgetType);
+                note.put(NoteColumns.ORIGIN_PARENT_ID, mOriginParent);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+
+                JSONArray dataArray = new JSONArray();
+                for (SqlData sqlData : mDataList) {
+                    JSONObject data = sqlData.getContent();
+                    if (data != null) {
+                        dataArray.put(data);
+                    }
+                }
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+            } else if (mType == Notes.TYPE_FOLDER || mType == Notes.TYPE_SYSTEM) {
+                note.put(NoteColumns.ID, mId);
+                note.put(NoteColumns.TYPE, mType);
+                note.put(NoteColumns.SNIPPET, mSnippet);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+            }
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    // 设置父笔记ID
+    public void setParentId(long id) {
+        mParentId = id;
+        mDiffNoteValues.put(NoteColumns.PARENT_ID, id);
+    }
+
+    // 设置Google任务ID
+    public void setGtaskId(String gid) {
+        mDiffNoteValues.put(NoteColumns.GTASK_ID, gid);
+    }
+
+    // 设置同步ID
+    public void setSyncId(long syncId) {
+        mDiffNoteValues.put(NoteColumns.SYNC_ID, syncId);
+    }
+
+    // 重置本地修改
+    public void resetLocalModified() {
+        mDiffNoteValues.put(NoteColumns.LOCAL_MODIFIED, 0);
+    }
+
+    // 获取笔记ID
+    public long getId() {
+        return mId;
+    }
+
+    // 获取父笔记ID
+    public long getParentId() {
+        return mParentId;
+    }
+
+    // 获取笔记摘要
+    public String getSnippet() {
+        return mSnippet;
+    }
+
+    // 判断是否为笔记类型
+    public boolean isNoteType() {
+        return mType == Notes.TYPE_NOTE;
+    }
+
+    // 提交笔记数据到数据库
+    public void commit(boolean validateVersion) {
+        if (mIsCreate) {
+            if (mId == INVALID_ID && mDiffNoteValues.containsKey(NoteColumns.ID)) {
+                mDiffNoteValues.remove(NoteColumns.ID);
+            }
+
+            Uri uri = mContentResolver.insert(Notes.CONTENT_NOTE_URI, mDiffNoteValues);
+            try {
+                mId = Long.valueOf(uri.getPathSegments().get(1));
+            } catch (NumberFormatException e) {
+                Log.e(TAG, "Get note id error :" + e.toString());
+                throw new ActionFailureException("create note failed");
+            }
+            if (mId == 0) {
+                throw new IllegalStateException("Create thread id failed");
+            }
+
+            if (mType == Notes.TYPE_NOTE) {
+                for (SqlData sqlData : mDataList) {
+                    sqlData.commit(mId, false, -1);
+                }
+            }
+        } else {
+            if (mId <= 0 && mId != Notes.ID_ROOT_FOLDER && mId != Notes.ID_CALL_RECORD_FOLDER) {
+                Log.e(TAG, "No such note");
+                throw new IllegalStateException("Try to update note with invalid id");
+            }
+            if (mDiffNoteValues.size() > 0) {
+                mVersion++;
+                int result = 0;
+                if (!validateVersion) {
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                            + NoteColumns.ID + "=?)", new String[] {
+                        String.valueOf(mId)
+                    });
+                } else {
+                    result = mContentResolver.update(Notes.CONTENT_NOTE_URI, mDiffNoteValues, "("
+                            + NoteColumns.ID + "=?) AND (" + NoteColumns.VERSION + "<=?)",
+                            new
+
+String[] {
+String.valueOf(mId), String.valueOf(mVersion)
+});
+}
+if (result == 0) {
+Log.w(TAG, "there is no update. maybe user updates note when syncing");
+}
+}
+
+

Task.java

@@ -0,0 +1,366 @@
+// 版权声明
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的包
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+// Task类继承自Node类，表示一个任务
+public class Task extends Node {
+    // 类的标签，用于日志记录
+    private static final String TAG = Task.class.getSimpleName();
+
+    // 成员变量
+    private boolean mCompleted; // 表示任务是否完成
+    private String mNotes; // 任务的备注信息
+    private JSONObject mMetaInfo; // 任务的元数据信息
+    private Task mPriorSibling; // 表示任务在任务列表中的前一个任务
+    private TaskList mParent; // 表示任务所属的任务列表
+
+    // 构造函数
+    public Task() {
+        super(); // 调用父类的构造函数
+        mCompleted = false; // 默认任务未完成
+        mNotes = null; // 初始没有备注信息
+        mPriorSibling = null; // 初始没有前一个任务
+        mParent = null; // 初始没有所属的任务列表
+        mMetaInfo = null; // 初始没有元数据信息
+    }
+
+    // 生成创建任务的JSON对象
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject(); // 创建一个空的JSON对象
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mParent.getChildTaskIndex(this));
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_TASK);
+            if (getNotes() != null) {
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+            // parent_id
+            js.put(GTaskStringUtils.GTASK_JSON_PARENT_ID, mParent.getGid());
+
+            // dest_parent_type
+            js.put(GTaskStringUtils.GTASK_JSON_DEST_PARENT_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+
+            // list_id
+            js.put(GTaskStringUtils.GTASK_JSON_LIST_ID, mParent.getGid());
+
+            // prior_sibling_id
+            if (mPriorSibling != null) {
+                js.put(GTaskStringUtils.GTASK_JSON_PRIOR_SIBLING_ID, mPriorSibling.getGid());
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-create jsonobject");
+        }
+
+        return js;
+    }
+
+    // 生成更新任务的JSON对象
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            if (getNotes() != null) {
+                entity.put(GTaskStringUtils.GTASK_JSON_NOTES, getNotes());
+            }
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate task-update jsonobject");
+        }
+
+        return js;
+    }
+
+    // 根据远程JSON对象设置任务内容
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }
+
+                // notes
+                if (js.has(GTaskStringUtils.GTASK_JSON_NOTES)) {
+                    setNotes(js.getString(GTaskStringUtils.GTASK_JSON_NOTES));
+                }
+
+                // deleted
+                if (js.has(GTaskStringUtils.GTASK_JSON_DELETED)) {
+                    setDeleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_DELETED));
+                }
+
+                // completed
+                if (js.has(GTaskStringUtils.GTASK_JSON_COMPLETED)) {
+                    setCompleted(js.getBoolean(GTaskStringUtils.GTASK_JSON_COMPLETED));
+                }
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get task content from jsonobject");
+            }
+        }
+    }
+
+    // 根据本地JSON对象设置任务内容
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)
+                || !js.has(GTaskStringUtils.META_HEAD_DATA)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is available");
+        }
+
+        try {
+            JSONObject note = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+            JSONArray dataArray = js.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+            if (note.getInt(NoteColumns.TYPE) != Notes.TYPE_NOTE) {
+                Log.e(TAG, "invalid type");
+                return;
+            }
+
+            for (int i = 0; i < dataArray.length(); i++) {
+                JSONObject data = dataArray.getJSONObject(i);
+                if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                    setName(data.getString(DataColumns.CONTENT));
+                    break;
+                }
+            }
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    // 从内容生成本地JSON对象
+    public JSONObject getLocalJSONFromContent() {
+        String name = getName();
+        try {
+            if (mMetaInfo == null) {
+                // new task created from web
+                if (name == null) {
+                    Log.w(TAG, "the note seems to be an empty one");
+                    return null;
+                }
+
+                JSONObject js = new JSONObject();
+                JSONObject note = new JSONObject();
+                JSONArray dataArray = new JSONArray();
+                JSONObject data = new JSONObject();
+                data.put(DataColumns.CONTENT, name);
+                dataArray.put(data);
+                js.put(GTaskStringUtils.META_HEAD_DATA, dataArray);
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                js.put(GTaskStringUtils.META_HEAD_NOTE, note);
+                return js;
+            } else {
+                // synced task
+                JSONObject note = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+                JSONArray dataArray = mMetaInfo.getJSONArray(GTaskStringUtils.META_HEAD_DATA);
+
+                for (int i = 0; i < dataArray.length(); i++) {
+                    JSONObject data = dataArray.getJSONObject(i);
+                    if (TextUtils.equals(data.getString(DataColumns.MIME_TYPE), DataConstants.NOTE)) {
+                        data.put(DataColumns.CONTENT, getName());
+                        break;
+                    }
+                }
+
+                note.put(NoteColumns.TYPE, Notes.TYPE_NOTE);
+                return mMetaInfo;
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    // 设置任务的元数据信息
+    public void setMetaInfo(MetaData metaData) {
+        if (metaData != null && metaData.getNotes() != null) {
+            try {
+                mMetaInfo = new JSONObject(metaData.getNotes());
+            } catch (JSONException e) {
+                Log.w(TAG, e.toString());
+                mMetaInfo = null;
+}
+}
+}
+
+// 确定同步操作类型
+public int getSyncAction(Cursor c) {
+    try {
+        JSONObject noteInfo = null;
+        if (mMetaInfo != null && mMetaInfo.has(GTaskStringUtils.META_HEAD_NOTE)) {
+            noteInfo = mMetaInfo.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+        }
+
+        if (noteInfo == null) {
+            Log.w(TAG, "it seems that note meta has been deleted");
+            return SYNC_ACTION_UPDATE_REMOTE;
+        }
+
+        if (!noteInfo.has(NoteColumns.ID)) {
+            Log.w(TAG, "remote note id seems to be deleted");
+            return SYNC_ACTION_UPDATE_LOCAL;
+        }
+
+        // validate the note id now
+        if (c.getLong(SqlNote.ID_COLUMN) != noteInfo.getLong(NoteColumns.ID)) {
+            Log.w(TAG, "note id doesn't match");
+            return SYNC_ACTION_UPDATE_LOCAL;
+        }
+
+        if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+            // there is no local update
+            if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                // no update both side
+                return SYNC_ACTION_NONE;
+            } else {
+                // apply remote to local
+                return SYNC_ACTION_UPDATE_LOCAL;
+            }
+        } else {
+            // validate gtask id
+            if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                Log.e(TAG, "gtask id doesn't match");
+                return SYNC_ACTION_ERROR;
+            }
+            if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                // local modification only
+                return SYNC_ACTION_UPDATE_REMOTE;
+            } else {
+                return SYNC_ACTION_UPDATE_CONFLICT;
+            }
+        }
+    } catch (Exception e) {
+        Log.e(TAG, e.toString());
+        e.printStackTrace();
+    }
+
+    return SYNC_ACTION_ERROR;
+}
+
+// 判断任务是否值得保存
+public boolean isWorthSaving() {
+    return mMetaInfo != null || (getName() != null && getName().trim().length() > 0)
+            || (getNotes() != null && getNotes().trim().length() > 0);
+}
+
+// 设置任务是否完成
+public void setCompleted(boolean completed) {
+    this.mCompleted = completed;
+}
+
+// 设置任务的备注信息
+public void setNotes(String notes) {
+    this.mNotes = notes;
+}
+
+// 设置任务在任务列表中的前一个任务
+public void setPriorSibling(Task priorSibling) {
+    this.mPriorSibling = priorSibling;
+}
+
+// 设置任务所属的任务列表
+public void setParent(TaskList parent) {
+    this.mParent = parent;
+}
+
+// 获取任务是否完成
+public boolean getCompleted() {
+    return this.mCompleted;
+}
+
+// 获取任务的备注信息
+public String getNotes() {
+    return this.mNotes;
+}
+
+// 获取任务在任务列表中的前一个任务
+public Task getPriorSibling() {
+    return this.mPriorSibling;
+}
+
+// 获取任务所属的任务列表
+public TaskList getParent() {
+    return this.mParent;
+}

TaskList.java

@@ -0,0 +1,363 @@
+// 版权声明和许可证信息
+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// 导入所需的包
+package net.micode.notes.gtask.data;
+
+import android.database.Cursor;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.exception.ActionFailureException;
+import net.micode.notes.tool.GTaskStringUtils;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.util.ArrayList;
+
+// TaskList类继承自Node类，用于表示一个任务列表
+public class TaskList extends Node {
+    // 类的标签，用于日志记录
+    private static final String TAG = TaskList.class.getSimpleName();
+
+    // 成员变量
+    private int mIndex; // 任务列表的索引
+    private ArrayList<Task> mChildren; // 任务列表中的任务
+
+    // 构造函数
+    public TaskList() {
+        super(); // 调用父类的构造函数
+        mChildren = new ArrayList<Task>(); // 初始化任务列表
+        mIndex = 1; // 默认索引为1
+    }
+
+    // 生成创建任务列表的JSON对象
+    public JSONObject getCreateAction(int actionId) {
+        JSONObject js = new JSONObject(); // 创建一个空的JSON对象
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_CREATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // index
+            js.put(GTaskStringUtils.GTASK_JSON_INDEX, mIndex);
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_CREATOR_ID, "null");
+            entity.put(GTaskStringUtils.GTASK_JSON_ENTITY_TYPE,
+                    GTaskStringUtils.GTASK_JSON_TYPE_GROUP);
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-create jsonobject");
+        }
+
+        return js;
+    }
+
+    // 生成更新任务列表的JSON对象
+    public JSONObject getUpdateAction(int actionId) {
+        JSONObject js = new JSONObject();
+
+        try {
+            // action_type
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_TYPE,
+                    GTaskStringUtils.GTASK_JSON_ACTION_TYPE_UPDATE);
+
+            // action_id
+            js.put(GTaskStringUtils.GTASK_JSON_ACTION_ID, actionId);
+
+            // id
+            js.put(GTaskStringUtils.GTASK_JSON_ID, getGid());
+
+            // entity_delta
+            JSONObject entity = new JSONObject();
+            entity.put(GTaskStringUtils.GTASK_JSON_NAME, getName());
+            entity.put(GTaskStringUtils.GTASK_JSON_DELETED, getDeleted());
+            js.put(GTaskStringUtils.GTASK_JSON_ENTITY_DELTA, entity);
+
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            throw new ActionFailureException("fail to generate tasklist-update jsonobject");
+        }
+
+        return js;
+    }
+
+    // 根据远程JSON对象设置任务列表内容
+    public void setContentByRemoteJSON(JSONObject js) {
+        if (js != null) {
+            try {
+                // id
+                if (js.has(GTaskStringUtils.GTASK_JSON_ID)) {
+                    setGid(js.getString(GTaskStringUtils.GTASK_JSON_ID));
+                }
+
+                // last_modified
+                if (js.has(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED)) {
+                    setLastModified(js.getLong(GTaskStringUtils.GTASK_JSON_LAST_MODIFIED));
+                }
+
+                // name
+                if (js.has(GTaskStringUtils.GTASK_JSON_NAME)) {
+                    setName(js.getString(GTaskStringUtils.GTASK_JSON_NAME));
+                }
+
+            } catch (JSONException e) {
+                Log.e(TAG, e.toString());
+                e.printStackTrace();
+                throw new ActionFailureException("fail to get tasklist content from jsonobject");
+            }
+        }
+    }
+
+    // 根据本地JSON对象设置任务列表内容
+    public void setContentByLocalJSON(JSONObject js) {
+        if (js == null || !js.has(GTaskStringUtils.META_HEAD_NOTE)) {
+            Log.w(TAG, "setContentByLocalJSON: nothing is available");
+        }
+
+        try {
+            JSONObject folder = js.getJSONObject(GTaskStringUtils.META_HEAD_NOTE);
+
+            if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_FOLDER) {
+                String name = folder.getString(NoteColumns.SNIPPET);
+                setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + name);
+            } else if (folder.getInt(NoteColumns.TYPE) == Notes.TYPE_SYSTEM) {
+                if (folder.getLong(NoteColumns.ID) == Notes.ID_ROOT_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX + GTaskStringUtils.FOLDER_DEFAULT);
+                else if (folder.getLong(NoteColumns.ID) == Notes.ID_CALL_RECORD_FOLDER)
+                    setName(GTaskStringUtils.MIUI_FOLDER_PREFFIX
+                            + GTaskStringUtils.FOLDER_CALL_NOTE);
+                else
+                    Log.e(TAG, "invalid system folder");
+            } else {
+                Log.e(TAG, "error type");
+            }
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+    }
+
+    // 从内容生成本地JSON对象
+    public JSONObject getLocalJSONFromContent() {
+        try {
+            JSONObject js = new JSONObject();
+            JSONObject folder = new JSONObject();
+
+            String folderName = getName();
+            if (getName().startsWith(GTaskStringUtils.MIUI_FOLDER_PREFFIX))
+                folderName = folderName.substring(GTaskStringUtils.MIUI_FOLDER_PREFFIX.length(),
+                        folderName.length());
+            folder.put(NoteColumns.SNIPPET, folderName);
+            if (folderName.equals(GTaskStringUtils.FOLDER_DEFAULT)
+                    || folderName.equals(GTaskStringUtils.FOLDER_CALL_NOTE))
+                folder.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+            else
+                folder.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+
+            js.put(GTaskStringUtils.META_HEAD_NOTE, folder);
+
+            return js;
+        } catch (JSONException e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+            return null;
+        }
+    }
+
+    // 确定同步操作类型
+    public int getSyncAction(Cursor c) {
+        try {
+            if (c.getInt(SqlNote.LOCAL_MODIFIED_COLUMN) == 0) {
+                // there is no local update
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // no update both side
+                    return SYNC_ACTION_NONE;
+                } else {
+                    // apply remote to local
+                    return SYNC_ACTION_UPDATE_LOCAL;
+                }
+            } else {
+                // validate gtask id
+                if (!c.getString(SqlNote.GTASK_ID_COLUMN).equals(getGid())) {
+                    Log.e(TAG, "gtask id doesn't match");
+                    return SYNC_ACTION_ERROR;
+                }
+                if (c.getLong(SqlNote.SYNC_ID_COLUMN) == getLastModified()) {
+                    // local modification only
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                } else {
+                    // for folder conflicts, just apply local modification
+                    return SYNC_ACTION_UPDATE_REMOTE;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, e.toString());
+            e.printStackTrace();
+        }
+
+        return SYNC_ACTION_ERROR;
+    }
+
+    // 获取子任务的数量
+    public int getChildTaskCount() {
+        return mChildren.size();
+    }
+
+    // 添加子任务
+    public boolean addChildTask(Task task) {
+        boolean ret = false;
+        if (task != null && !mChildren.contains(task)) {
+            ret = mChildren.add(task);
+            if (ret) {
+                // need to set prior sibling and parent
+                task.setPriorSibling(mChildren.isEmpty() ? null : mChildren
+                        .get(mChildren.size() - 1));
+                task.setParent(this);
+            }
+        }
+        return ret;
+    }
+
+    // 在指定位置添加子任务
+    public boolean addChildTask(Task task, int index) {
+        if (index < 0 || index > mChildren.size()) {
+            Log.e(TAG, "add child task: invalid index");
+            return false;
+        }
+
+        int pos = mChildren.indexOf(task);
+        if (task != null && pos == -1) {
+            mChildren.add(index, task);
+
+            // update the task list
+            Task preTask = null;
+            Task afterTask = null;
+            if (index != 0)
+                preTask = mChildren.get(index - 1);
+            if (index != mChildren.size() - 1)
+                afterTask = mChildren.get(index + 1);
+
+            task.setPriorSibling(preTask);
+            if (afterTask != null)
+                afterTask.setPriorSibling(task);
+}
+    return true;
+}
+
+// 移除子任务
+public boolean removeChildTask(Task task) {
+    boolean ret = false;
+    int index = mChildren.indexOf(task);
+    if (index != -1) {
+        ret = mChildren.remove(task);
+
+        if (ret) {
+            // reset prior sibling and parent
+            task.setPriorSibling(null);
+            task.setParent(null);
+
+            // update the task list
+            if (index != mChildren.size()) {
+                mChildren.get(index).setPriorSibling(
+                        index == 0 ? null : mChildren.get(index - 1));
+            }
+        }
+    }
+    return ret;
+}
+
+// 移动子任务到指定位置
+public boolean moveChildTask(Task task, int index) {
+
+    if (index < 0 || index >= mChildren.size()) {
+        Log.e(TAG, "move child task: invalid index");
+        return false;
+    }
+
+    int pos = mChildren.indexOf(task);
+    if (pos == -1) {
+        Log.e(TAG, "move child task: the task should in the list");
+        return false;
+    }
+
+    if (pos == index)
+        return true;
+    return (removeChildTask(task) && addChildTask(task, index));
+}
+
+// 根据GID查找子任务
+public Task findChildTaskByGid(String gid) {
+    for (int i = 0; i < mChildren.size(); i++) {
+        Task t = mChildren.get(i);
+        if (t.getGid().equals(gid)) {
+            return t;
+        }
+    }
+    return null;
+}
+
+// 获取子任务的索引
+public int getChildTaskIndex(Task task) {
+    return mChildren.indexOf(task);
+}
+
+// 根据索引获取子任务
+public Task getChildTaskByIndex(int index) {
+    if (index < 0 || index >= mChildren.size()) {
+        Log.e(TAG, "getTaskByIndex: invalid index");
+        return null;
+    }
+    return mChildren.get(index);
+}
+
+// 根据GID获取子任务
+public Task getChilTaskByGid(String gid) {
+    for (Task task : mChildren) {
+        if (task.getGid().equals(gid))
+            return task;
+    }
+    return null;
+}
+
+// 获取子任务列表
+public ArrayList<Task> getChildTaskList() {
+    return this.mChildren;
+}
+
+// 设置索引
+public void setIndex(int index) {
+    this.mIndex = index;
+}
+
+// 获取索引
+public int getIndex() {
+    return this.mIndex;
+}

WorkingNote.java

@@ -0,0 +1,404 @@
+// 包声明，定义了该类所在的包名
+package net.micode.notes.model;
+
+// 导入所需的Android类库
+import android.appwidget.AppWidgetManager;
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+// 导入项目中定义的数据表和列名
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.Notes.TextNote;
+import net.micode.notes.tool.ResourceParser.NoteBgResources;
+
+// 定义WorkingNote类，用于表示一个工作便签
+public class WorkingNote {
+    // Note对象，用于操作便签数据
+    private Note mNote;
+    // 便签ID
+    private long mNoteId;
+    // 便签内容
+    private String mContent;
+    // 便签模式
+    private int mMode;
+
+    // 便签提醒日期
+    private long mAlertDate;
+
+    // 便签修改日期
+    private long mModifiedDate;
+
+    // 便签背景颜色ID
+    private int mBgColorId;
+
+    // 小部件ID
+    private int mWidgetId;
+
+    // 小部件类型
+    private int mWidgetType;
+
+    // 便签所在文件夹ID
+    private long mFolderId;
+
+    // 上下文对象
+    private Context mContext;
+
+    // 日志标签
+    private static final String TAG = "WorkingNote";
+
+    // 是否被删除
+    private boolean mIsDeleted;
+
+    // 便签设置更改监听器
+    private NoteSettingChangedListener mNoteSettingStatusListener;
+
+    // 数据查询投影
+    public static final String[] DATA_PROJECTION = new String[] {
+            DataColumns.ID,
+            DataColumns.CONTENT,
+            DataColumns.MIME_TYPE,
+            DataColumns.DATA1,
+            DataColumns.DATA2,
+            DataColumns.DATA3,
+            DataColumns.DATA4,
+    };
+
+    // 便签查询投影
+    public static final String[] NOTE_PROJECTION = new String[] {
+            NoteColumns.PARENT_ID,
+            NoteColumns.ALERTED_DATE,
+            NoteColumns.BG_COLOR_ID,
+            NoteColumns.WIDGET_ID,
+            NoteColumns.WIDGET_TYPE,
+            NoteColumns.MODIFIED_DATE
+    };
+
+    // 数据ID列索引
+    private static final int DATA_ID_COLUMN = 0;
+
+    // 数据内容列索引
+    private static final int DATA_CONTENT_COLUMN = 1;
+
+    // 数据MIME类型列索引
+    private static final int DATA_MIME_TYPE_COLUMN = 2;
+
+    // 数据模式列索引
+    private static final int DATA_MODE_COLUMN = 3;
+
+    // 便签父ID列索引
+    private static final int NOTE_PARENT_ID_COLUMN = 0;
+
+    // 便签提醒日期列索引
+    private static final int NOTE_ALERTED_DATE_COLUMN = 1;
+
+    // 便签背景颜色ID列索引
+    private static final int NOTE_BG_COLOR_ID_COLUMN = 2;
+
+    // 便签小部件ID列索引
+    private static final int NOTE_WIDGET_ID_COLUMN = 3;
+
+    // 便签小部件类型列索引
+    private static final int NOTE_WIDGET_TYPE_COLUMN = 4;
+
+    // 便签修改日期列索引
+    private static final int NOTE_MODIFIED_DATE_COLUMN = 5;
+
+    // 新建便签构造函数
+    private WorkingNote(Context context, long folderId) {
+        mContext = context;
+        mAlertDate = 0;
+        mModifiedDate = System.currentTimeMillis();
+        mFolderId = folderId;
+        mNote = new Note();
+        mNoteId = 0;
+        mIsDeleted = false;
+        mMode = 0;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+    }
+
+    // 现有便签构造函数
+    private WorkingNote(Context context, long noteId, long folderId) {
+        mContext = context;
+        mNoteId = noteId;
+        mFolderId = folderId;
+        mIsDeleted = false;
+        mNote = new Note();
+        loadNote();
+    }
+
+    // 加载便签数据
+    private void loadNote() {
+        Cursor cursor = mContext.getContentResolver().query(
+                ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, mNoteId), NOTE_PROJECTION, null,
+                null, null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                mFolderId = cursor.getLong(NOTE_PARENT_ID_COLUMN);
+                mBgColorId = cursor.getInt(NOTE_BG_COLOR_ID_COLUMN);
+                mWidgetId = cursor.getInt(NOTE_WIDGET_ID_COLUMN);
+                mWidgetType = cursor.getInt(NOTE_WIDGET_TYPE_COLUMN);
+                mAlertDate = cursor.getLong(NOTE_ALERTED_DATE_COLUMN);
+                mModifiedDate = cursor.getLong(NOTE_MODIFIED_DATE_COLUMN);
+            }
+            cursor.close();
+        } else {
+            Log.e(TAG, "No note with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note with id " + mNoteId);
+        }
+        loadNoteData();
+    }
+
+    // 加载便签数据内容
+    private void loadNoteData() {
+        Cursor cursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI, DATA_PROJECTION,
+                DataColumns.NOTE_ID + "=?", new String[] {
+                    String.valueOf(mNoteId)
+                }, null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                do {
+                    String type = cursor.getString(DATA_MIME_TYPE_COLUMN);
+                    if (DataConstants.NOTE.equals(type)) {
+                        mContent = cursor.getString(DATA_CONTENT_COLUMN);
+                        mMode = cursor.getInt(DATA_MODE_COLUMN);
+                        mNote.setTextDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else if (DataConstants.CALL_NOTE.equals(type)) {
+                        mNote.setCallDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else {
+                        Log.d(TAG, "Wrong note type with type:" + type);
+                    }
+                } while (cursor.moveToNext());
+            }
+            cursor.close();
+        } else {
+            Log.e(TAG, "No data with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note's data with id " + mNoteId);
+        }
+    }
+
+    // 创建空便签
+    public static WorkingNote createEmptyNote(Context context, long folderId, int widgetId,
+            int widgetType, int defaultBgColorId) {
+        WorkingNote note = new WorkingNote(context, folderId);
+        note.setBgColorId(defaultBgColorId);
+        note.setWidgetId(widgetId);
+        note.setWidgetType(widgetType);
+        return note;
+    }
+
+    // 加载便签
+    public static WorkingNote load(Context context, long id) {
+        return new WorkingNote(context, id, 0);
+    }
+
+    // 保存便签
+    public synchronized boolean saveNote() {
+        if (isWorthSaving()) {
+            if (!existInDatabase()) {
+                if ((mNoteId = Note.getNewNoteId(mContext, mFolderId)) == 0) {
+                    Log.e(TAG, "Create new note fail with id:" + mNoteId);
+                    return false;
+                }
+            }
+
+            mNote.syncNote(mContext, mNoteId);
+
+            /**
+             * Update widget content if there exist any widget of this note
+             */
+            if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                    && mWidgetType != Notes.TYPE_WIDGET_INVALIDE
+                    && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    // 判断便签是否存在于数据库中
+    public boolean existInDatabase() {
+        return mNoteId > 0;
+    }
+
+    // 判断便签是否值得保存
+    private boolean isWorthSaving() {
+        if (mIsDeleted || (!existInDatabase() && TextUtils.isEmpty(mContent))
+                || (existInDatabase() && !mNote.isLocalModified())) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    // 设置便签设置更改监听器
+    public void setOnSettingStatusChangedListener(NoteSettingChangedListener l) {
+        mNoteSettingStatusListener = l;
+    }
+
+    // 设置提醒日期
+    public void setAlertDate(long date, boolean set) {
+        if (date != mAlertDate) {
+            mAlertDate = date;
+            mNote.setNoteValue(NoteColumns.ALERTED_DATE, String.valueOf(mAlertDate));
+        }
+        if (mNoteSettingStatusListener != null) {
+            mNoteSettingStatusListener.onClockAlertChanged(date, set);
+        }
+    }
+
+    // 标记便签是否被删除
+    public void markDeleted(boolean mark) {
+        mIsDeleted = mark;
+        if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                && mWidgetType != Notes.TYPE_WIDGET_INVALIDE && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+        }
+    }
+
+    // 设置背景颜色ID
+    public void setBgColorId(int id) {
+        if (id != mBgColorId) {
+            mBgColorId =id;
+		if (mNoteSettingStatusListener != null) {
+			mNoteSettingStatusListener.onBackgroundColorChanged();
+		}
+		mNote.setNoteValue(NoteColumns.BG_COLOR_ID, String.valueOf(id));
+	}
+}
+// 设置检查列表模式
+public void setCheckListMode(int mode) {
+    if (mMode != mode) {
+        if (mNoteSettingStatusListener != null) {
+            mNoteSettingStatusListener.onCheckListModeChanged(mMode, mode);
+        }
+        mMode = mode;
+        mNote.setTextData(TextNote.MODE, String.valueOf(mMode));
+    }
+}
+
+// 设置小部件类型
+public void setWidgetType(int type) {
+    if (type != mWidgetType) {
+        mWidgetType = type;
+        mNote.setNoteValue(NoteColumns.WIDGET_TYPE, String.valueOf(mWidgetType));
+    }
+}
+
+// 设置小部件ID
+public void setWidgetId(int id) {
+    if (id != mWidgetId) {
+        mWidgetId = id;
+        mNote.setNoteValue(NoteColumns.WIDGET_ID, String.valueOf(mWidgetId));
+    }
+}
+
+// 设置工作文本
+public void setWorkingText(String text) {
+    if (!TextUtils.equals(mContent, text)) {
+        mContent = text;
+        mNote.setTextData(DataColumns.CONTENT, mContent);
+    }
+}
+
+// 转换为通话便签
+public void convertToCallNote(String phoneNumber, long callDate) {
+    mNote.setCallData(CallNote.CALL_DATE, String.valueOf(callDate));
+    mNote.setCallData(CallNote.PHONE_NUMBER, phoneNumber);
+    mNote.setNoteValue(NoteColumns.PARENT_ID, String.valueOf(Notes.ID_CALL_RECORD_FOLDER));
+}
+
+// 判断是否有提醒闹钟
+public boolean hasClockAlert() {
+    return (mAlertDate > 0 ? true : false);
+}
+
+// 获取便签内容
+public String getContent() {
+    return mContent;
+}
+
+// 获取提醒日期
+public long getAlertDate() {
+    return mAlertDate;
+}
+
+// 获取修改日期
+public long getModifiedDate() {
+    return mModifiedDate;
+}
+
+// 获取背景颜色资源ID
+public int getBgColorResId() {
+    return NoteBgResources.getNoteBgResource(mBgColorId);
+}
+
+// 获取背景颜色ID
+public int getBgColorId() {
+    return mBgColorId;
+}
+
+// 获取标题背景资源ID
+public int getTitleBgResId() {
+    return NoteBgResources.getNoteTitleBgResource(mBgColorId);
+}
+
+// 获取检查列表模式
+public int getCheckListMode() {
+    return mMode;
+}
+
+// 获取便签ID
+public long getNoteId() {
+    return mNoteId;
+}
+
+// 获取便签所在文件夹ID
+public long getFolderId() {
+    return mFolderId;
+}
+
+// 获取小部件ID
+public int getWidgetId() {
+    return mWidgetId;
+}
+
+// 获取小部件类型
+public int getWidgetType() {
+    return mWidgetType;
+}
+
+// 定义便签设置更改监听器接口
+public interface NoteSettingChangedListener {
+    /**
+     * Called when the background color of current note has just changed
+     */
+    void onBackgroundColorChanged();
+
+    /**
+     * Called when user set clock
+     */
+    void onClockAlertChanged(long date, boolean set);
+
+    /**
+     * Call when user create note from widget
+     */
+    void onWidgetChanged();
+
+    /**
+     * Call when switch between check list mode and normal mode
+     * @param oldMode is previous mode before change
+     * @param newMode is new mode
+     */
+    void onCheckListModeChanged(int oldMode, int newMode);
+}