v2

src/data/Contact.java

@@ -0,0 +1,90 @@
+/*
+ * 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.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;
+
+import java.util.HashMap;
+
+public class Contact {
+    // 定义一个静态的HashMap，用于缓存联系人信息
+    private static HashMap<String, String> sContactCache;
+    // 定义一个常量，用于打印日志
+    private static final String TAG = "Contact";
+
+    // 定义一个常量，用于查询联系人信息的SQL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 = '+')";
+
+ // 根据传入的上下文和电话号码获取联系人信息
+    public static String getContact(Context context, String phoneNumber) {
+        // 如果联系人缓存为空，则创建一个新的HashMap
+        if(sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+
+// 如果sContactCache中包含phoneNumber键
+        if(sContactCache.containsKey(phoneNumber)) {
+    // 返回sContactCache中phoneNumber键对应的值
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 将电话号码转换为Caller ID的最小匹配格式，并替换掉"+"号
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 通过ContentResolver查询Data表，获取电话号码对应的联系人姓名
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,
+                new String [] { Phone.DISPLAY_NAME },
+                selection,
+                new String[] { phoneNumber },
+                null);
+
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                // 获取联系人姓名
+                String name = cursor.getString(0);
+                // 将联系人姓名存入缓存
+                sContactCache.put(phoneNumber, name);
+                // 返回联系人姓名
+                return name;
+            } catch (IndexOutOfBoundsException e) {
+                // 捕获索引越界异常
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                // 返回null
+                return null;
+            } finally {
+                // 关闭游标
+                cursor.close();
+            }
+        } else {
+            // 没有匹配的联系人
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            // 返回null
+            return null;
+        }
+    }
+}

src/data/Notes.java

@@ -0,0 +1,327 @@
+/*
+ * 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.net.Uri;
+public class Notes {
+    // 定义Notes类的权限
+    public static final String AUTHORITY = "micode_notes";
+    // 定义Notes类的标签
+    public static final String TAG = "Notes";
+    // 定义Notes类的类型：笔记
+    public static final int TYPE_NOTE     = 0;
+    // 定义Notes类的类型：文件夹
+    public static final int TYPE_FOLDER   = 1;
+    // 定义Notes类的类型：系统
+    public static final int TYPE_SYSTEM   = 2;
+
+    /**
+     * 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ID
+    public static final int ID_TEMPARAY_FOLDER = -1; // 临时文件夹ID
+    public static final int ID_CALL_RECORD_FOLDER = -2; // 呼叫记录文件夹ID
+    public static final int ID_TRASH_FOLER = -3; // 回收站文件夹ID
+
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date"; // 提醒日期
+    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"; // 呼叫日期
+
+    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 {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE; // 文本笔记类型
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE; // 呼叫笔记类型
+    }
+
+    /**
+     * Uri to query all notes and folders
+     */
+// 定义一个常量，表示Note表的Uri
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * Uri to query data
+     */
+// 定义一个常量，表示内容提供者的数据URI
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 定义一个常量，表示ID
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+// 定义一个常量，表示父节点的ID
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+    // 声明一个常量，表示创建日期
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 定义一个常量，表示修改日期
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 定义一个常量，表示警报日期
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+// 定义一个常量，用于表示代码片段
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+  // 声明一个常量，用于表示小部件的ID
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 声明一个常量，表示小部件类型
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+// 定义一个常量，用于表示背景颜色的ID
+        public static final String BG_COLOR_ID = "bg_color_id";
+
+        /**
+         * For text note, it doesn't has attachment, for multi-media
+         * note, it has at least one attachment
+         * <P> Type: INTEGER </P>
+         */
+// 定义一个常量，表示是否有附件
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 定义一个常量，表示笔记数量
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+// 定义一个常量，表示类型
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+ // 定义一个常量，用于同步的ID
+        public static final String SYNC_ID = "sync_id";
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+  // 定义一个常量，表示本地修改
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+// 定义一个常量，表示原始父级ID
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+// 定义一个常量，用于存储任务ID
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+ // 定义一个常量，表示版本号
+        public static final String VERSION = "version";
+    }
+
+ // 定义一个接口DataColumns
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+// 定义一个常量，表示ID
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+ // 定义一个常量，表示MIME类型
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+// 定义一个常量，表示笔记的ID
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+  // 声明一个常量，表示创建日期
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+    // 声明一个常量，表示修改日期
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+ // 定义一个常量CONTENT，值为"content"
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+ // 定义一个常量DATA1，值为"data1"
+// 定义一个常量DATA1，值为"data1"
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+  // 定义一个常量DATA2，值为"data2"
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+ // 定义一个常量DATA3，值为"data3"
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+// 定义一个常量DATA4，值为"data4"
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+ // 定义一个常量DATA5，值为"data5"
+        public static final String DATA5 = "data5";
+    }
+
+    // 实现DataColumns接口的TextNote类
+    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;
+
+        // 定义一个常量，表示检查列表的模式
+        public static final int MODE_CHECK_LIST = 1;
+
+        // 定义一个常量，表示内容类型为文本笔记
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+        // 定义一个常量，表示内容项类型为文本笔记
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        // 定义一个常量，表示内容URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }
+
+    // 定义一个名为CallNote的公共静态内部类，实现DataColumns接口
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+  // 定义一个常量，表示调用日期
+        public static final String CALL_DATE = DATA1;
+
+        /**
+         * Phone number for this record
+         * <P> Type: TEXT </P>
+         */
+ // 定义一个常量，表示电话号码
+        public static final String PHONE_NUMBER = DATA3;
+
+ // 定义一个常量，表示内容类型
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
+
+ // 定义一个常量，表示内容项类型
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
+
+ // 定义一个常量，表示内容URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }
+}

src/data/NotesDatabaseHelper.java

@@ -0,0 +1,489 @@
+/*
+ * 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.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;
+
+
+public class NotesDatabaseHelper extends SQLiteOpenHelper {
+    // 数据库名称
+    private static final String DB_NAME = "note.db";
+
+    // 数据库版本号
+    private static final int DB_VERSION = 4;
+
+    // 数据库表名
+    public interface TABLE {
+        public static final String NOTE = "note";
+
+        public static final String DATA = "data";
+    }
+
+    // 日志标签
+    private static final String TAG = "NotesDatabaseHelper";
+
+    // 数据库实例
+    private static NotesDatabaseHelper mInstance;
+
+// 定义创建NOTE表的SQL语句
+    private static final String CREATE_NOTE_TABLE_SQL =
+        "CREATE TABLE " + TABLE.NOTE + "(" +
+            // 定义ID列，类型为INTEGER，为主键
+            NoteColumns.ID + " INTEGER PRIMARY KEY," +
+            // 定义PARENT_ID列，类型为INTEGER，默认值为0
+            NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义ALERTED_DATE列，类型为INTEGER，默认值为0
+            NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义BG_COLOR_ID列，类型为INTEGER，默认值为0
+            NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义CREATED_DATE列，类型为INTEGER，默认值为当前时间戳
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            // 定义HAS_ATTACHMENT列，类型为INTEGER，默认值为0
+            NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义MODIFIED_DATE列，类型为INTEGER，默认值为当前时间戳
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+            // 定义NOTES_COUNT列，类型为INTEGER，默认值为0
+            NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义SNIPPET列，类型为TEXT，默认值为空字符串
+            NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
+            // 定义TYPE列，类型为INTEGER，默认值为0
+            NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义WIDGET_ID列，类型为INTEGER，默认值为0
+            NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义WIDGET_TYPE列，类型为INTEGER，默认值为-1
+            NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
+            // 定义SYNC_ID列，类型为INTEGER，默认值为0
+            NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义LOCAL_MODIFIED列，类型为INTEGER，默认值为0
+            NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义ORIGIN_PARENT_ID列，类型为INTEGER，默认值为0
+            NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+            // 定义GTASK_ID列，类型为TEXT，默认值为空字符串
+            NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
+            // 定义VERSION列，类型为INTEGER，默认值为0
+            NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
+        ")";
+
+    private static final String CREATE_DATA_TABLE_SQL =
+        "CREATE TABLE " + TABLE.DATA + "(" +
+
+            // 创建数据表，包含ID、MIME_TYPE、NOTE_ID、CREATED_DATE、MODIFIED_DATE、CONTENT、DATA1、DATA2、DATA3、DATA4、DATA5等字段
+            DataColumns.ID + " INTEGER PRIMARY KEY," + // ID字段，主键
+            DataColumns.MIME_TYPE + " TEXT NOT NULL," + // MIME_TYPE字段，文本类型，不能为空
+            DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," + // NOTE_ID字段，整型，不能为空，默认值为0
+            NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," + // CREATED_DATE字段，整型，不能为空，默认值为当前时间戳
+            NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," + // MODIFIED_DATE字段，整型，不能为空，默认值为当前时间戳
+            DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," + // CONTENT字段，文本类型，不能为空，默认值为空字符串
+            DataColumns.DATA1 + " INTEGER," + // DATA1字段，整型
+            DataColumns.DATA2 + " INTEGER," + // DATA2字段，整型
+            DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," + // DATA3字段，文本类型，不能为空，默认值为空字符串
+            DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," + // DATA4字段，文本类型，不能为空，默认值为空字符串
+            DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" + // DATA5字段，文本类型，不能为空，默认值为空字符串
+        ")";
+
+ // 创建一个名为note_id_index的索引，如果不存在则创建
+    private static final String CREATE_DATA_NOTE_ID_INDEX_SQL =
+        "CREATE INDEX IF NOT EXISTS note_id_index ON " +
+        TABLE.DATA + "(" + DataColumns.NOTE_ID + ");";
+
+    /**
+     * Increase folder's note count when move note to the folder
+     */
+// 定义一个静态常量，用于创建一个触发器，在更新Note表的PARENT_ID字段后，增加对应文件夹的NOTES_COUNT字段
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+  // 创建一个触发器，当更新文件夹时，增加文件夹数量
+        "CREATE TRIGGER increase_folder_count_on_update "+ // 创建一个触发器，名称为increase_folder_count_on_update
+        " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE + // 在Note表上，当PARENT_ID字段更新后
+        " BEGIN " + // 开始
+  // 更新表TABLE.NOTE，将NoteColumns.NOTES_COUNT字段加1
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+        // 条件为NoteColumns.ID等于new.NoteColumns.PARENT_ID
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+        " END";
+
+    /**
+     * Decrease folder's note count when move note from folder
+     */
+ // 定义一个常量，用于在更新触发器上减少文件夹计数
+ // 定义一个常量，用于表示在更新触发器中减少文件夹数量的操作
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER decrease_folder_count_on_update " +
+// 添加注释
+        " 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 +
+        // 检查旧记录的父ID是否与当前记录的ID相同
+        "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+        " END";
+
+    /**
+     * Increase folder's note count when insert new note to the folder
+     */
+  // 定义一个常量，用于表示在插入时增加文件夹数量的触发器
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+        "CREATE TRIGGER increase_folder_count_on_insert " +
+        " AFTER INSERT ON " + TABLE.NOTE + // 在NOTE表上创建一个名为increase_folder_count_on_insert的触发器
+        " BEGIN " +
+        "  UPDATE " + TABLE.NOTE + // 更新NOTE表
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + // 将NOTES_COUNT字段加1
+        "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + // 条件为ID等于新记录的PARENT_ID
+        " END";
+
+    /**
+     * Decrease folder's note count when delete note from the folder
+     */
+ // 定义一个常量，用于在删除文件夹时减少文件夹计数器的触发器
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+// 创建一个触发器，在删除NOTE表中的数据后，减少FOLDER表中的文件夹数量
+        "CREATE TRIGGER decrease_folder_count_on_delete " +
+        " AFTER DELETE ON " + TABLE.NOTE +
+        " BEGIN " +
+// 更新表"TABLE.NOTE"，将"NoteColumns.NOTES_COUNT"字段的值减1
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+        // 在"NoteColumns.ID"字段的值等于"old." + NoteColumns.PARENT_ID"的情况下
+        "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+        // 并且"NoteColumns.NOTES_COUNT"字段的值大于0的情况下
+        "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+        " END";
+
+    /**
+     * Update note's content when insert data with type {@link DataConstants#NOTE}
+     */
+// 定义一个常量，用于表示在插入数据时更新备注内容的触发器
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+// 创建一个触发器，在插入数据后更新笔记内容
+        "CREATE TRIGGER update_note_content_on_insert " +
+        " AFTER INSERT ON " + TABLE.DATA +
+        " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+  // 更新表NOTE，将SNIPPET字段设置为new表中的CONTENT字段
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        // 如果NOTE_ID字段等于new表中的NOTE_ID字段
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has changed
+     */
+   // 定义一个常量，用于更新触发器时更新数据注释的内容
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_update " +
+        " AFTER UPDATE ON " + TABLE.DATA + // 创建一个名为update_note_content_on_update的触发器，在更新TABLE.DATA表之后执行
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+// 更新数据库中指定表的数据
+        "  UPDATE " + TABLE.NOTE +
+        // 设置指定列的值为新值
+        "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+        // 指定更新条件
+        "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has deleted
+     */
+ // 定义一个常量，用于表示删除触发器时更新数据注释的内容
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+        "CREATE TRIGGER update_note_content_on_delete " + // 创建一个名为update_note_content_on_delete的触发器
+        " AFTER delete ON " + TABLE.DATA + // 在删除操作后触发
+        " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+        " BEGIN" +
+ // 更新表NOTE，将SNIPPET字段设置为空字符串
+        "  UPDATE " + TABLE.NOTE +
+        "   SET " + NoteColumns.SNIPPET + "=''" +
+// 添加条件，只更新ID等于old.Note_ID的记录
+        "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+        " END";
+
+    /**
+     * Delete datas belong to note which has been deleted
+     */
+// 定义一个常量，用于删除触发器时删除数据
+    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";
+
+    /**
+     * Delete notes belong to folder which has been deleted
+     */
+ // 定义一个常量，用于删除文件夹时触发删除笔记的触发器
+    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";
+
+    /**
+     * Move notes belong to folder which has been moved to trash folder
+     */
+// 定义一个静态常量，用于创建一个触发器，当更新Note表时，如果新父ID等于垃圾文件夹ID，则将旧父ID更新为垃圾文件夹ID
+// 私有静态常量，用于触发将文件夹移动到垃圾桶的操作
+    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，传入上下文参数，调用父类的构造函数，初始化数据库
+    public NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+// 创建Note表，执行SQL语句，重新创建Note表触发器，创建系统文件夹，并打印日志
+    public void createNoteTable(SQLiteDatabase db) {
+// 执行创建笔记表的SQL语句
+        db.execSQL(CREATE_NOTE_TABLE_SQL);
+// 重新创建笔记表触发器
+        reCreateNoteTableTriggers(db);
+ // 创建系统文件夹
+        createSystemFolder(db);
+// 打印日志信息，表示note表已经创建
+        Log.d(TAG, "note table has been created");
+    }
+
+   // 重新创建NoteTable触发器
+    private void reCreateNoteTableTriggers(SQLiteDatabase db) {
+        // 删除increase_folder_count_on_update触发器
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update");
+        // 删除decrease_folder_count_on_update触发器
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_update");
+        // 删除decrease_folder_count_on_delete触发器
+        db.execSQL("DROP TRIGGER IF EXISTS decrease_folder_count_on_delete");
+        // 删除delete_data_on_delete触发器
+        db.execSQL("DROP TRIGGER IF EXISTS delete_data_on_delete");
+        // 删除increase_folder_count_on_insert触发器
+        db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_insert");
+        // 删除folder_delete_notes_on_delete触发器
+        db.execSQL("DROP TRIGGER IF EXISTS folder_delete_notes_on_delete");
+        // 删除folder_move_notes_on_trash触发器
+        db.execSQL("DROP TRIGGER IF EXISTS folder_move_notes_on_trash");
+
+ // 执行增加文件夹计数触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+ // 执行减少文件夹计数触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+ // 执行减少文件夹计数触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
+ // 执行删除数据触发器
+        db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
+ // 执行增加文件夹计数触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
+ // 执行删除文件夹触发器
+        db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
+ // 执行移动文件夹触发器
+        db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
+    }
+
+// 创建一个方法，用于创建系统文件夹
+    private void createSystemFolder(SQLiteDatabase db) {
+        // 创建一个ContentValues对象，用于存储数据
+        ContentValues values = new ContentValues();
+
+        /**
+         * call record foler for call notes
+         */
+ // 将Notes.ID_CALL_RECORD_FOLDER的值放入values中
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+ // 将Notes.TYPE_SYSTEM的值放入values中
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+ // 将values中的值插入到TABLE.NOTE表中
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * root folder which is default folder
+         */
+ // 清空values
+        values.clear();
+ // 将Notes.ID_ROOT_FOLDER放入values中
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+ // 将Notes.TYPE_SYSTEM放入values中
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+ // 将values插入到TABLE.NOTE表中
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * temporary folder which is used for moving note
+         */
+ // 清空values
+        values.clear();
+ // 将NoteColumns.ID的值设为Notes.ID_TEMPARAY_FOLDER
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+ // 将NoteColumns.TYPE的值设为Notes.TYPE_SYSTEM
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+ // 将values插入到TABLE.NOTE表中
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * create trash folder
+         */
+        // 清空values
+        values.clear();
+        // 将ID设置为垃圾桶文件夹的ID
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        // 将类型设置为系统类型
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        // 将values插入到NOTE表中
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+   // 创建数据表
+    public void createDataTable(SQLiteDatabase db) {
+        // 执行创建数据表的SQL语句
+        db.execSQL(CREATE_DATA_TABLE_SQL);
+        // 重新创建数据表触发器
+        reCreateDataTableTriggers(db);
+        // 执行创建数据表索引的SQL语句
+        db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
+        // 打印日志，表示数据表已经创建
+        Log.d(TAG, "data table has been created");
+    }
+
+    private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        // 删除已有的触发器
+        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");
+
+        // 创建新的触发器
+        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NotesDatabaseHelper实例
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        // 如果实例为空，则创建新的实例
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        // 返回实例
+        return mInstance;
+    }
+
+    // 创建数据库表
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        // 创建note表
+        createNoteTable(db);
+        // 创建data表
+        createDataTable(db);
+    }
+
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        // 定义两个布尔变量，用于判断是否需要重新创建触发器和跳过v2版本
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        // 如果旧版本是1，则升级到v2版本，并跳过v2版本
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // this upgrade including the upgrade from v2 to v3
+            oldVersion++;
+        }
+
+        // 如果旧版本是2，并且没有跳过v2版本，则升级到v3版本，并重新创建触发器
+        if (oldVersion == 2 && !skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+
+        // 如果旧版本为3，则升级到版本4
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+
+        // 如果需要重新创建触发器，则重新创建笔记表和数据表触发器
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+
+        // 如果旧版本不等于新版本，则抛出异常
+        if (oldVersion != newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }
+
+    private void upgradeToV2(SQLiteDatabase db) {
+        // 删除旧版本的NOTE表
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
+        // 删除旧版本的DATA表
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
+        // 创建新版本的NOTE表
+        createNoteTable(db);
+        // 创建新版本的DATA表
+        createDataTable(db);
+    }
+
+// 将数据库升级到V3版本
+    private void upgradeToV3(SQLiteDatabase db) {
+        // drop unused triggers
+// 删除名为update_note_modified_date_on_insert的触发器，如果存在
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+ // 删除名为update_note_modified_date_on_delete的触发器
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+ // 删除名为update_note_modified_date_on_update的触发器
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+        // add a column for gtask id
+// 向数据库中的NOTE表添加一个名为GTASK_ID的列，类型为TEXT，默认值为空字符串
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+        // add a trash system folder
+  // 创建一个ContentValues对象，用于存储要插入的数据
+        ContentValues values = new ContentValues();
+  // 将ID_TRASH_FOLER的值放入ContentValues对象中
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+  // 将TYPE_SYSTEM的值放入ContentValues对象中
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+  // 将ContentValues对象中的数据插入到数据库的NOTE表中
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+ // 将数据库升级到V4版本
+    private void upgradeToV4(SQLiteDatabase db) {
+      // 执行SQL语句，在NOTE表中添加一个名为VERSION的列，类型为INTEGER，默认值为0
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");
+    }
+}

src/data/NotesProvider.java

@@ -0,0 +1,441 @@
+/*
+ * 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;
+
+
+public class NotesProvider extends ContentProvider {
+    // 定义一个UriMatcher对象，用于匹配Uri
+    private static final UriMatcher mMatcher;
+
+    // 定义一个NotesDatabaseHelper对象，用于操作数据库
+    private NotesDatabaseHelper mHelper;
+
+// 定义一个常量，用于标识NotesProvider
+    private static final String TAG = "NotesProvider";
+
+// 定义一个常量，用于标识URI_NOTE
+    private static final int URI_NOTE            = 1;
+// 定义一个常量，用于标识URI_NOTE_ITEM
+    private static final int URI_NOTE_ITEM       = 2;
+// 定义一个常量，用于标识URI_DATA
+    private static final int URI_DATA            = 3;
+// 定义一个常量，用于标识URI_DATA_ITEM
+    private static final int URI_DATA_ITEM       = 4;
+
+// 定义一个常量，用于标识URI_SEARCH
+    private static final int URI_SEARCH          = 5;
+// 定义一个常量，用于标识URI_SEARCH_SUGGEST
+    private static final int URI_SEARCH_SUGGEST  = 6;
+
+// 静态代码块，用于初始化UriMatcher对象
+    static {
+        // 创建UriMatcher对象，NO_MATCH表示没有匹配的URI
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的note，匹配成功返回URI_NOTE
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的note/#，匹配成功返回URI_NOTE_ITEM
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的data，匹配成功返回URI_DATA
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的data/#，匹配成功返回URI_DATA_ITEM
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的search，匹配成功返回URI_SEARCH
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的search/*，匹配成功返回URI_SEARCH_SUGGEST
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
+        // 添加URI匹配规则，匹配Notes.AUTHORITY下的search/*/*，匹配成功返回URI_SEARCH_SUGGEST
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
+    }
+
+    /**
+     * 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.
+     */
+// 定义一个常量，用于搜索笔记的投影
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+        // 将笔记的ID作为搜索建议的额外数据
+        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+        // 将笔记的摘要作为搜索建议的文本1
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+        // 将笔记的摘要作为搜索建议的文本2
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+        // 将搜索结果的图标设置为drawable/search_result
+        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+        // 将搜索建议的意图动作设置为Intent.ACTION_VIEW
+        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+        // 将搜索建议的意图数据设置为Notes.TextNote.CONTENT_TYPE
+        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+
+// 定义一个静态字符串变量，用于查询笔记片段
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+        // 查询笔记片段
+        + " FROM " + TABLE.NOTE
+        // 从笔记表中查询
+        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+        // 笔记片段匹配查询条件
+        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+        // 笔记的父ID不等于垃圾桶文件夹
+        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    // 重写onCreate方法
+    public boolean onCreate() {
+        // 获取NotesDatabaseHelper的实例
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        // 返回true
+        return true;
+    }
+
+    @Override
+    // 重写query方法，用于查询数据
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+            String sortOrder) {
+        // 声明一个Cursor对象
+        Cursor c = null;
+        // 获取可读的数据库
+        SQLiteDatabase db = mHelper.getReadableDatabase();
+        // 声明一个id变量
+        String id = null;
+ // 根据传入的uri，执行不同的数据库查询操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 查询note表
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                // 查询note表中指定id的记录
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                // 查询data表
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                // 查询data表中指定id的记录
+                id = uri.getPathSegments().get(1);
+// 查询数据库中指定表的数据，返回一个Cursor对象
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+  // 搜索URI
+            case URI_SEARCH:
+            // 搜索建议URI
+            case URI_SEARCH_SUGGEST:
+                // 查询搜索结果
+// 如果sortOrder不为空或者projection不为空，则抛出异常
+                if (sortOrder != null || projection != null) {
+// 抛出IllegalArgumentException异常，异常信息为："do not specify sortOrder, selection, selectionArgs, or projection" + "with this query"
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
+                }
+
+ // 获取搜索字符串
+                String searchString = null;
+ // 如果匹配到URI_SEARCH_SUGGEST
+                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
+     // 如果URI的路径段大于1
+                    if (uri.getPathSegments().size() > 1) {
+         // 获取路径段的第二个元素作为搜索字符串
+                        searchString = uri.getPathSegments().get(1);
+                    }
+                } else {
+                    // 获取uri中的查询参数pattern
+                    searchString = uri.getQueryParameter("pattern");
+                }
+
+                // 如果查询参数为空，则返回null
+                if (TextUtils.isEmpty(searchString)) {
+                    return null;
+                }
+
+                try {
+                    // 将搜索字符串格式化为包含通配符的字符串
+                    searchString = String.format("%%%s%%", searchString);
+                    // 执行查询语句，返回结果集
+                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
+                            new String[] { searchString });
+                } catch (IllegalStateException ex) {
+                    // 捕获异常并打印错误日志
+                    Log.e(TAG, "got exception: " + ex.toString());
+                }
+                break;
+            default:
+                // 抛出异常，表示未知的URI
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // 如果结果集不为空，则设置通知URI
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        // 返回结果集
+        return c;
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        // 获取可写的数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        // 定义变量，用于存储插入的数据ID
+        long dataId = 0, noteId = 0, insertedId = 0;
+        // 根据传入的URI进行匹配
+        switch (mMatcher.match(uri)) {
+            // 如果匹配到URI_NOTE
+            case URI_NOTE:
+                // 在NOTE表中插入数据，并获取插入的数据ID
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+            // 如果匹配到URI_DATA
+            case URI_DATA:
+                // 如果values中包含NOTE_ID
+                if (values.containsKey(DataColumns.NOTE_ID)) {
+                    // 获取NOTE_ID
+                    noteId = values.getAsLong(DataColumns.NOTE_ID);
+                } else {
+                    // 否则，打印错误日志
+                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
+                }
+                // 在DATA表中插入数据，并获取插入的数据ID
+                insertedId = dataId = db.insert(TABLE.DATA, null, values);
+                break;
+            // 如果没有匹配到任何URI
+            default:
+                // 抛出异常
+                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);
+    }
+
+    @Override
+    public int delete(Uri uri, String selection, String[] selectionArgs) {
+        // 初始化删除的记录数
+        int count = 0;
+        // 初始化ID
+        String id = null;
+        // 获取可写的数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        // 初始化删除数据标志
+        boolean deleteData = false;
+        // 根据URI匹配不同的删除操作
+        switch (mMatcher.match(uri)) {
+            // 删除笔记
+            case URI_NOTE:
+                // 添加删除条件
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
+                // 执行删除操作
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);
+                break;
+            // 删除笔记项
+            case URI_NOTE_ITEM:
+                // 获取笔记项的ID
+                id = uri.getPathSegments().get(1);
+                /**
+                 * ID that smaller than 0 is system folder which is not allowed to
+                 * trash
+                 */
+                // 将id转换为long类型
+                long noteId = Long.valueOf(id);
+                // 如果noteId小于等于0，则跳出循环
+                if (noteId <= 0) {
+                    break;
+                }
+                // 删除指定id的note
+     // 删除指定ID的笔记
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                break;
+            // 处理URI_DATA
+            case URI_DATA:
+   // 删除数据
+                count = db.delete(TABLE.DATA, selection, selectionArgs);
+   // 标记删除数据
+                deleteData = true;
+                break;
+// 删除数据项
+            case URI_DATA_ITEM:
+   // 获取数据项的id
+                id = uri.getPathSegments().get(1);
+   // 删除数据项
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+   // 标记删除数据
+                deleteData = true;
+                break;
+// 未知URI
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+// 如果删除了数据
+        if (count > 0) {
+   // 如果删除了数据，通知内容解析器
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+   // 通知内容解析器
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+// 返回删除的条数
+        return count;
+    }
+
+    // 重写update方法，用于更新数据库中的数据
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        // 定义一个计数器，用于记录更新的数据条数
+        int count = 0;
+        // 定义一个字符串，用于存储要更新的数据的id
+        String id = null;
+        // 获取可写的数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        // 定义一个布尔值，用于判断是否更新了数据
+        boolean updateData = false;
+ // 根据传入的uri进行匹配，根据匹配结果执行不同的操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 增加note的版本号
+                increaseNoteVersion(-1, selection, selectionArgs);
+                // 更新note表
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                // 获取uri中的id
+                id = uri.getPathSegments().get(1);
+                // 增加note的版本号
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
+                // 更新note表
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                // 更新data表
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);
+                // 标记更新data
+                updateData = true;
+                break;
+            case URI_DATA_ITEM:
+                // 获取uri中的id
+                id = uri.getPathSegments().get(1);
+                // 更新data表
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                // 标记更新data
+                updateData = true;
+                break;
+            default:
+                // 抛出异常，未知uri
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+
+// 如果count大于0
+        if (count > 0) {
+    // 如果updateData为true
+            if (updateData) {
+        // 通知ContentResolver更新Notes.CONTENT_NOTE_URI
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+    // 通知ContentResolver更新uri
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+// 返回count
+        return count;
+    }
+
+// 解析selection字符串
+    private String parseSelection(String selection) {
+    // 如果selection不为空
+        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
+    }
+
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+        // 创建一个StringBuilder对象，用于拼接SQL语句
+        StringBuilder sql = new StringBuilder(120);
+        // 拼接UPDATE语句
+        sql.append("UPDATE ");
+        // 拼接表名
+        sql.append(TABLE.NOTE);
+        // 拼接SET语句
+        sql.append(" SET ");
+        // 拼接版本号字段
+        sql.append(NoteColumns.VERSION);
+        // 拼接版本号增加1的语句
+        sql.append("=" + NoteColumns.VERSION + "+1 ");
+
+        // 如果id大于0或者selection不为空，则拼接WHERE语句
+        if (id > 0 || !TextUtils.isEmpty(selection)) {
+            sql.append(" WHERE ");
+        }
+        // 如果id大于0，则拼接id等于指定值的语句
+        if (id > 0) {
+            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
+        }
+ // 判断selection是否为空
+        if (!TextUtils.isEmpty(selection)) {
+            // 如果id大于0，则调用parseSelection方法解析selection，否则直接赋值给selectString
+            String selectString = id > 0 ? parseSelection(selection) : selection;
+            // 遍历selectionArgs数组，将每个元素替换selectString中的第一个问号
+            for (String args : selectionArgs) {
+                selectString = selectString.replaceFirst("\\?", args);
+            }
+            // 将selectString追加到sql中
+            sql.append(selectString);
+        }
+
+// 获取可写的数据库
+        mHelper.getWritableDatabase().execSQL(sql.toString());
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        // 获取Uri的类型
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}

src/tool/BackupUtils.java

@@ -0,0 +1,492 @@
+/*
+ * 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.tool;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.os.Environment;
+import android.text.TextUtils;
+import android.text.format.DateFormat;
+import android.util.Log;
+
+import net.micode.notes.R;
+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 java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+
+
+public class BackupUtils {
+    // 定义一个常量，用于打印日志
+    private static final String TAG = "BackupUtils";
+    // Singleton stuff
+    // 定义一个静态变量，用于保存BackupUtils的实例
+    private static BackupUtils sInstance;
+
+ // 获取BackupUtils实例
+    public static synchronized BackupUtils getInstance(Context context) {
+        // 如果sInstance为空，则创建一个新的BackupUtils实例
+        if (sInstance == null) {
+            sInstance = new BackupUtils(context);
+        }
+        // 返回sInstance实例
+        return sInstance;
+    }
+
+    /**
+     * Following states are signs to represents backup or restore
+     * status
+     */
+    // Currently, the sdcard is not mounted
+ // 定义一个常量，表示SD卡未挂载的状态
+    public static final int STATE_SD_CARD_UNMOUONTED           = 0;
+    // The backup file not exist
+// 定义一个常量，表示备份文件不存在
+    public static final int STATE_BACKUP_FILE_NOT_EXIST        = 1;
+    // The data is not well formated, may be changed by other programs
+ // 定义一个常量，表示数据被销毁的状态
+    public static final int STATE_DATA_DESTROIED               = 2;
+    // Some run-time exception which causes restore or backup fails
+ // 定义一个常量，表示系统错误状态
+    public static final int STATE_SYSTEM_ERROR                 = 3;
+    // Backup or restore success
+ // 定义一个常量，表示成功状态
+    public static final int STATE_SUCCESS                      = 4;
+
+ // 声明一个TextExport类型的变量mTextExport
+    private TextExport mTextExport;
+
+// 定义一个BackupUtils类，构造函数接收一个Context参数
+    private BackupUtils(Context context) {
+        // 创建一个TextExport对象，传入Context参数
+        mTextExport = new TextExport(context);
+    }
+
+ // 检查外部存储是否可用
+    private static boolean externalStorageAvailable() {
+        // 返回外部存储的状态是否为MEDIA_MOUNTED
+        return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
+    }
+
+    // 导出为文本文件
+    public int exportToText() {
+        // 调用mTextExport对象的exportToText方法
+        return mTextExport.exportToText();
+    }
+
+    // 获取导出的文本文件名
+    public String getExportedTextFileName() {
+        // 返回mTextExport对象的mFileName属性
+        return mTextExport.mFileName;
+    }
+
+    // 获取导出的文本文件目录
+    public String getExportedTextFileDir() {
+        // 返回mTextExport对象的mFileDirectory属性
+        return mTextExport.mFileDirectory;
+    }
+
+// 定义一个静态内部类TextExport
+    private static class TextExport {
+        // 定义一个常量数组NOTE_PROJECTION，包含NoteColumns中的ID、MODIFIED_DATE、SNIPPET、TYPE四个字段
+        private static final String[] NOTE_PROJECTION = {
+// 获取NoteColumns中的ID、MODIFIED_DATE、SNIPPET字段
+ // NoteColumns.ID 表示Note表的ID列
+                NoteColumns.ID,
+// 添加注释
+                NoteColumns.MODIFIED_DATE, // 修改日期
+// 定义NoteColumns类中的SNIPPET常量
+                NoteColumns.SNIPPET,
+ // 定义一个常量，表示NoteColumns中的TYPE列
+                NoteColumns.TYPE
+        };
+
+ // 定义一个常量，表示笔记的ID列
+        private static final int NOTE_COLUMN_ID = 0;
+
+ // 定义一个常量，表示笔记的修改日期列
+        private static final int NOTE_COLUMN_MODIFIED_DATE = 1;
+
+ // 定义一个常量，表示笔记的摘要列
+        private static final int NOTE_COLUMN_SNIPPET = 2;
+
+// 定义一个常量数组，用于存储数据投影
+        private static final String[] DATA_PROJECTION = {
+ // 数据列
+                DataColumns.CONTENT,
+ // 数据列的MIME类型
+                DataColumns.MIME_TYPE,
+ // 数据列1
+                DataColumns.DATA1,
+                DataColumns.DATA2,
+                DataColumns.DATA3,
+                DataColumns.DATA4,
+        };
+
+// 定义一个常量，表示数据列的内容
+        private static final int DATA_COLUMN_CONTENT = 0;
+
+ // 定义一个常量，表示数据列的MIME类型
+        private static final int DATA_COLUMN_MIME_TYPE = 1;
+
+// 定义一个常量，表示数据列的调用日期
+        private static final int DATA_COLUMN_CALL_DATE = 2;
+
+// 定义一个常量，表示数据列中的电话号码列的索引
+        private static final int DATA_COLUMN_PHONE_NUMBER = 4;
+
+// 声明一个字符串数组，用于存储文本格式
+        private final String [] TEXT_FORMAT;
+// 定义一个常量，表示文件夹名称的格式
+        private static final int FORMAT_FOLDER_NAME          = 0;
+ // 定义常量，表示日期格式
+        private static final int FORMAT_NOTE_DATE            = 1;
+ // 定义常量，表示格式化笔记内容的格式
+        private static final int FORMAT_NOTE_CONTENT         = 2;
+
+// 定义一个Context类型的成员变量
+        private Context mContext;
+// 声明一个字符串类型的私有变量mFileName
+        private String mFileName;
+ // 文件目录
+        private String mFileDirectory;
+
+// 构造函数，用于创建TextExport对象
+        public TextExport(Context context) {
+// 获取导出笔记的格式数组
+            TEXT_FORMAT = context.getResources().getStringArray(R.array.format_for_exported_note);
+  // 保存上下文
+            mContext = context;
+  // 初始化文件名为空字符串
+            mFileName = "";
+  // 初始化文件目录为空字符串
+            mFileDirectory = "";
+        }
+
+// 根据id获取格式
+        private String getFormat(int id) {
+// 返回TEXT_FORMAT数组中索引为id的元素
+            return TEXT_FORMAT[id];
+        }
+
+        /**
+// 导出由folder id标识的文件夹到文本
+         * Export the folder identified by folder id to text
+         */
+// 将文件夹导出到文本文件
+        private void exportFolderToText(String folderId, PrintStream ps) {
+            // Query notes belong to this folder
+// 获取指定文件夹下的所有笔记
+            Cursor notesCursor = mContext.getContentResolver().query(Notes.CONTENT_NOTE_URI,
+// 定义一个常量，用于查询Note表中的数据
+                    NOTE_PROJECTION, NoteColumns.PARENT_ID + "=?", new String[] {
+// 定义一个变量folderId，用于存储文件夹的ID
+                        folderId
+// 定义一个无符号长整型变量
+                    }, null);
+
+// 判断notesCursor是否为空
+            if (notesCursor != null) {
+// 如果notesCursor指向的数据表中有数据
+                if (notesCursor.moveToFirst()) {
+                    do {
+                        // Print note's last modified date
+// 打印日期
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+// 获取字符串资源，格式为"yyyy-MM-dd HH:mm"
+                                mContext.getString(R.string.format_datetime_mdhm),
+// 获取notesCursor中NOTE_COLUMN_MODIFIED_DATE列的值，并将其转换为long类型
+                                notesCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // Query data belong to this note
+// 从notesCursor中获取NOTE_COLUMN_ID列的值，并将其赋值给noteId变量
+                        String noteId = notesCursor.getString(NOTE_COLUMN_ID);
+// 导出笔记到文本
+                        exportNoteToText(noteId, ps);
+// 使用while循环遍历notesCursor中的数据
+                    } while (notesCursor.moveToNext());
+                }
+// 关闭游标
+                notesCursor.close();
+            }
+        }
+
+        /**
+         * Export note identified by id to a print stream
+         */
+// 将笔记导出到文本文件
+        private void exportNoteToText(String noteId, PrintStream ps) {
+ // 获取Notes表中的数据
+            Cursor dataCursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI,
+  // 查询数据，指定投影为DATA_PROJECTION，条件为DataColumns.NOTE_ID等于noteId，不指定排序
+                    DATA_PROJECTION, DataColumns.NOTE_ID + "=?", new String[] {
+                        noteId
+                    }, null);
+
+            // 如果dataCursor不为空
+            if (dataCursor != null) {
+// 如果dataCursor可以移动到第一行
+                if (dataCursor.moveToFirst()) {
+// do 关键字用于开始一个循环，循环体内的代码会一直执行，直到遇到 break 关键字
+                    do {
+  // 获取数据的光标
+                        String mimeType = dataCursor.getString(DATA_COLUMN_MIME_TYPE);
+// 判断mimeType是否等于DataConstants.CALL_NOTE
+                        if (DataConstants.CALL_NOTE.equals(mimeType)) {
+                            // Print phone number
+// 从dataCursor中获取电话号码
+                            String phoneNumber = dataCursor.getString(DATA_COLUMN_PHONE_NUMBER);
+// 获取dataCursor中DATA_COLUMN_CALL_DATE列的值，并将其赋值给callDate变量
+                            long callDate = dataCursor.getLong(DATA_COLUMN_CALL_DATE);
+  // 获取数据光标中指定列的字符串值
+                            String location = dataCursor.getString(DATA_COLUMN_CONTENT);
+
+// 判断phoneNumber是否为空
+                            if (!TextUtils.isEmpty(phoneNumber)) {
+// 打印格式化后的字符串
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        phoneNumber));
+                            }
+                            // Print call date
+// 打印格式化后的字符串
+                            ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT), DateFormat
+                                    // 格式化日期
+                                    .format(mContext.getString(R.string.format_datetime_mdhm),
+                                            callDate)));
+                            // Print call attachment location
+// 判断location是否为空
+                            if (!TextUtils.isEmpty(location)) {
+    // 使用String.format方法将location格式化为指定格式，并打印输出
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        location));
+                            }
+                        } else if (DataConstants.NOTE.equals(mimeType)) {
+                            // 获取数据内容
+                            String content = dataCursor.getString(DATA_COLUMN_CONTENT);
+                            // 如果内容不为空
+                            if (!TextUtils.isEmpty(content)) {
+                                // 打印格式化后的内容
+                                ps.println(String.format(getFormat(FORMAT_NOTE_CONTENT),
+                                        content));
+                            }
+                        }
+// 如果dataCursor可以移动到下一个位置，则继续循环
+                    } while (dataCursor.moveToNext());
+                }
+                dataCursor.close();
+            }
+            // print a line separator between note
+            try {
+                // 向ps写入一个换行符和一个字母数字字符
+                ps.write(new byte[] {
+                        Character.LINE_SEPARATOR, Character.LETTER_NUMBER
+                });
+            } catch (IOException e) {
+                // 捕获IOException异常，并打印错误日志
+                Log.e(TAG, e.toString());
+            }
+        }
+
+        /**
+         * Note will be exported as text which is user readable
+         */
+        public int exportToText() {
+            // 检查外部存储是否可用
+            if (!externalStorageAvailable()) {
+                // 如果外部存储不可用，则输出日志信息
+                Log.d(TAG, "Media was not mounted");
+                // 返回SD卡未挂载状态
+                return STATE_SD_CARD_UNMOUONTED;
+            }
+
+ // 获取导出到文本的PrintStream
+            PrintStream ps = getExportToTextPrintStream();
+ // 如果获取失败
+            if (ps == null) {
+     // 打印错误日志
+                Log.e(TAG, "get print stream error");
+     // 返回系统错误状态
+                return STATE_SYSTEM_ERROR;
+            }
+            // First export folder and its notes
+// 查询数据库，获取文件夹和通话记录文件夹的信息
+            Cursor folderCursor = mContext.getContentResolver().query(
+ // 定义一个常量，表示笔记的URI
+                    Notes.CONTENT_NOTE_URI,
+ // 声明一个名为NOTE_PROJECTION的常量
+                    NOTE_PROJECTION,
+                    "(" + NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + " AND "
+                            + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER + ") OR "
+                            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER, null, null);
+
+// 如果folderCursor不为空
+            if (folderCursor != null) {
+// 如果游标指向的数据集不为空
+                if (folderCursor.moveToFirst()) {
+                    do {
+                        // Print folder's name
+ // 声明一个字符串变量folderName，用于存储文件夹名称
+                        String folderName = "";
+// 如果文件夹游标中的ID等于Notes中的ID_CALL_RECORD_FOLDER，则将文件夹名称设置为上下文中的call_record_folder_name字符串
+                        if(folderCursor.getLong(NOTE_COLUMN_ID) == Notes.ID_CALL_RECORD_FOLDER) {
+                            folderName = mContext.getString(R.string.call_record_folder_name);
+// 如果文件夹名称为空，则从游标中获取文件夹名称
+                        } else {
+                            folderName = folderCursor.getString(NOTE_COLUMN_SNIPPET);
+                        }
+// 判断folderName是否为空
+                        if (!TextUtils.isEmpty(folderName)) {
+    // 使用String.format方法将folderName格式化为指定格式，并输出到ps流中
+                            ps.println(String.format(getFormat(FORMAT_FOLDER_NAME), folderName));
+                        }
+ // 获取文件夹ID
+                        String folderId = folderCursor.getString(NOTE_COLUMN_ID);
+ // 将文件夹导出到文本
+                        exportFolderToText(folderId, ps);
+ // 移动到下一个文件夹
+                    } while (folderCursor.moveToNext());
+                }
+// 关闭文件夹游标
+                folderCursor.close();
+            }
+
+            // Export notes in root's folder
+// 获取一个游标，查询Notes表中type为Notes.TYPE_NOTE且parent_id为0的数据            Cursor noteCursor = mContext.getContentResolver().query(
+            Cursor noteCursor = mContext.getContentResolver().query(
+// 定义一个Notes类，其中包含一个CONTENT_NOTE_URI常量，用于表示Notes表的URI
+                    Notes.CONTENT_NOTE_URI,
+ // 定义一个常量，用于表示投影
+                    NOTE_PROJECTION,
+  // 拼接查询条件，查询类型为Notes.TYPE_NOTE且父ID为NoteColumns.PARENT_ID的记录
+                    NoteColumns.TYPE + "=" + +Notes.TYPE_NOTE + " AND " + NoteColumns.PARENT_ID
+                            + "=0", null, null);
+
+ // 如果noteCursor不为空
+            if (noteCursor != null) {
+// 如果游标移动到第一行
+                if (noteCursor.moveToFirst()) {
+                    do {
+  // 打印笔记的修改日期
+                        ps.println(String.format(getFormat(FORMAT_NOTE_DATE), DateFormat.format(
+                                mContext.getString(R.string.format_datetime_mdhm),
+                                noteCursor.getLong(NOTE_COLUMN_MODIFIED_DATE))));
+                        // Query data belong to this note
+ // 获取当前游标中的noteId
+                        String noteId = noteCursor.getString(NOTE_COLUMN_ID);
+ // 将noteId导出到文本中
+                        exportNoteToText(noteId, ps);
+ // 如果游标还有下一个元素，则继续循环
+                    } while (noteCursor.moveToNext());
+                }
+// 关闭游标
+                noteCursor.close();
+            }
+// 关闭ps
+            ps.close();
+
+// 返回成功状态
+            return STATE_SUCCESS;
+        }
+
+        /**
+         * Get a print stream pointed to the file {@generateExportedTextFile}
+         */
+        private PrintStream getExportToTextPrintStream() {
+            // 生成一个挂载在SD卡上的文件
+            File file = generateFileMountedOnSDcard(mContext, R.string.file_path,
+                    R.string.file_name_txt_format);
+            // 如果文件生成失败，则返回null
+            if (file == null) {
+                Log.e(TAG, "create file to exported failed");
+                return null;
+            }
+            // 获取文件名
+            mFileName = file.getName();
+            // 获取文件路径
+            mFileDirectory = mContext.getString(R.string.file_path);
+            PrintStream ps = null;
+            try {
+                // 创建文件输出流
+                FileOutputStream fos = new FileOutputStream(file);
+                // 创建PrintStream对象
+                ps = new PrintStream(fos);
+            } catch (FileNotFoundException e) {
+                // 文件未找到异常，打印异常信息
+                e.printStackTrace();
+                return null;
+            } catch (NullPointerException e) {
+                // 空指针异常，打印异常信息
+                e.printStackTrace();
+                return null;
+            }
+            // 返回PrintStream对象
+            return ps;
+        }
+    }
+
+    /**
+     * Generate the text file to store imported data
+     */
+// 生成一个挂载在SD卡上的文件
+    private static File generateFileMountedOnSDcard(Context context, int filePathResId, int fileNameFormatResId) {
+        // 创建一个StringBuilder对象
+        StringBuilder sb = new StringBuilder();
+        // 将SD卡的根目录添加到StringBuilder中
+        sb.append(Environment.getExternalStorageDirectory());
+        // 将文件路径字符串添加到StringBuilder中
+        sb.append(context.getString(filePathResId));
+        // 创建一个File对象，表示文件路径
+        File filedir = new File(sb.toString());
+        // 将文件名格式字符串添加到StringBuilder中
+        sb.append(context.getString(
+                fileNameFormatResId,
+                // 使用当前时间格式化文件名
+                DateFormat.format(context.getString(R.string.format_date_ymd),
+                        System.currentTimeMillis())));
+        // 创建一个File对象，表示文件名
+        File file = new File(sb.toString());
+
+        try {
+            // 如果文件路径不存在，则创建文件夹
+            if (!filedir.exists()) {
+                filedir.mkdir();
+            }
+            // 如果文件不存在，则创建文件
+            if (!file.exists()) {
+                file.createNewFile();
+            }
+            // 返回文件对象
+            return file;
+        } catch (SecurityException e) {
+            // 捕获SecurityException异常，并打印异常信息
+            e.printStackTrace();
+        } catch (IOException e) {
+            // 捕获IOException异常，并打印异常信息
+            e.printStackTrace();
+        }
+
+ // 返回null
+        return null;
+    }
+}
+
+

src/tool/DataUtils.java

@@ -0,0 +1,417 @@
+/*
+ * 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.tool;
+
+import android.content.ContentProviderOperation;
+import android.content.ContentProviderResult;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.OperationApplicationException;
+import android.database.Cursor;
+import android.os.RemoteException;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+
+public class DataUtils {
+    public static final String TAG = "DataUtils";
+    // 批量删除笔记
+    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {
+        // 如果ids为空，则直接返回true
+ // 判断ids是否为空
+        if (ids == null) {
+            // 如果为空，打印日志
+            Log.d(TAG, "the ids is null");
+            // 返回true
+            return true;
+        }
+// 判断ids的大小是否为0
+        if (ids.size() == 0) {
+            // 如果为0，则输出日志信息
+            Log.d(TAG, "no id is in the hashset");
+            // 返回true
+            return true;
+        }
+
+// 创建一个ContentProviderOperation的ArrayList
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+// 遍历ids数组中的每一个id
+        for (long id : ids) {
+    // 如果id等于Notes.ID_ROOT_FOLDER，则输出错误日志，并跳过此次循环
+            if(id == Notes.ID_ROOT_FOLDER) {
+ // 打印错误日志，提示不要删除系统文件夹root
+                Log.e(TAG, "Don't delete system folder root");
+ // 继续执行循环
+                continue;
+            }
+// 创建一个ContentProviderOperation.Builder对象，用于构建一个删除操作
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+// 将构建好的删除操作添加到操作列表中
+            operationList.add(builder.build());
+        }
+        try {
+            // 调用ContentResolver的applyBatch方法，批量删除notes
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            // 如果返回的结果为空或者长度为0或者第一个结果为空，则删除失败
+// 判断results是否为空，或者results的长度是否为0，或者results的第一个元素是否为空
+            if (results == null || results.length == 0 || results[0] == null) {
+// 打印删除笔记失败的日志，并输出失败笔记的id
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException e) {
+            // 打印RemoteException异常信息
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            // 打印OperationApplicationException异常信息
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        // 返回false
+        return false;
+    }
+
+    // 移动笔记到文件夹
+    public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
+        // 创建一个ContentValues对象，用于存储要更新的数据
+        ContentValues values = new ContentValues();
+        // 将目标文件夹ID存储到ContentValues对象中
+        values.put(NoteColumns.PARENT_ID, desFolderId);
+        // 将原始文件夹ID存储到ContentValues对象中
+        values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
+        // 将本地修改标志设置为1
+        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+        // 使用ContentResolver对象更新指定ID的笔记，将ContentValues对象中的数据应用到该笔记中
+        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);
+    }
+
+    // 批量移动笔记到文件夹
+    public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
+            long folderId) {
+        // 检查ids是否为空
+        if (ids == null) {
+            // 如果为空，打印日志
+            Log.d(TAG, "the ids is null");
+            // 返回true
+            return true;
+        }
+
+// 创建一个ContentProviderOperation的ArrayList
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+// 遍历ids数组
+        for (long id : ids) {
+    // 创建一个ContentProviderOperation.Builder对象，用于构建ContentProviderOperation
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+    // 设置PARENT_ID字段的值为folderId
+            builder.withValue(NoteColumns.PARENT_ID, folderId);
+    // 设置LOCAL_MODIFIED字段的值为1
+            builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
+    // 将构建好的ContentProviderOperation添加到operationList中
+            operationList.add(builder.build());
+        }
+
+        try {
+            // 调用ContentResolver的applyBatch方法，批量执行操作
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            // 如果结果为空或者长度为0或者第一个结果为空，则删除失败
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            // 否则删除成功
+            return true;
+// 捕获RemoteException异常
+        } catch (RemoteException e) {
+            // 打印异常信息
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            // 打印异常信息
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        // 返回false
+        return false;
+    }
+
+    /**
+     * Get the all folder count except system folders {@link Notes#TYPE_SYSTEM}}
+     */
+    public static int getUserFolderCount(ContentResolver resolver) {
+        // 查询Notes.CONTENT_NOTE_URI，获取COUNT(*)，条件为NoteColumns.TYPE为Notes.TYPE_FOLDER且NoteColumns.PARENT_ID不为Notes.ID_TRASH_FOLER
+        Cursor cursor =resolver.query(Notes.CONTENT_NOTE_URI,
+// 创建一个包含一个字符串的数组，字符串内容为 "COUNT(*)"
+                new String[] { "COUNT(*)" },
+// 查询类型为指定类型且父ID不等于指定值的记录
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+// 创建一个包含两个元素的字符串数组，第一个元素是Notes.TYPE_FOLDER的值，第二个元素是Notes.ID_TRASH_FOLER的值
+                new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
+// 第二个参数为null
+                null);
+
+ // 定义一个整型变量count，并初始化为0
+        int count = 0;
+// 判断游标是否为空
+        if(cursor != null) {
+    // 将游标移动到第一行
+            if(cursor.moveToFirst()) {
+                try {
+            // 获取第一列的整数值
+                    count = cursor.getInt(0);
+                } catch (IndexOutOfBoundsException e) {
+            // 捕获IndexOutOfBoundsException异常，并打印错误日志
+                    Log.e(TAG, "get folder count failed:" + e.toString());
+                } finally {
+            // 关闭游标
+                    cursor.close();
+                }
+            }
+        }
+// 返回count
+        return count;
+    }
+
+    public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
+        // 查询指定noteId的笔记，类型为type，且父文件夹不为垃圾箱
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null,
+  // 查询条件：类型等于某个值，并且父ID不等于垃圾文件夹的ID
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
+                new String [] {String.valueOf(type)}, // 将type转换为字符串并添加到字符串数组中
+                null); // 添加一个空值
+
+        boolean exist = false;
+        // 判断游标是否为空
+        if (cursor != null) {
+            // 判断游标中的数据是否大于0
+            if (cursor.getCount() > 0) {
+                // 如果大于0，则存在数据
+                exist = true;
+            }
+            // 关闭游标
+            cursor.close();
+        }
+ // 返回exist变量
+        return exist;
+    }
+
+    public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
+        // 查询指定noteId的笔记是否存在
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            // 如果查询结果不为空，则说明笔记存在
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            // 关闭查询结果
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
+        // 查询指定dataId的数据是否存在
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            // 如果查询结果不为空，则说明数据存在
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            // 关闭查询结果
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
+        // 查询数据库，查找是否存在同名的可见文件夹
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
+// 添加注释
+                NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER + // 查询文件夹类型的笔记
+                " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
+                " AND " + NoteColumns.SNIPPET + "=?",
+                new String[] { name }, null);
+        boolean exist = false;
+        if(cursor != null) {
+            // 如果查询结果不为空，则说明存在同名的可见文件夹
+            if(cursor.getCount() > 0) {
+                exist = true;
+            }
+            // 关闭游标
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
+        // 查询指定文件夹下的所有便签
+        Cursor c = resolver.query(Notes.CONTENT_NOTE_URI,
+                // 查询便签的widget_id和widget_type字段
+                new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
+                // 查询条件为便签的parent_id等于folderId
+                NoteColumns.PARENT_ID + "=?",
+                // 查询条件参数
+                new String[] { String.valueOf(folderId) },
+                null);
+
+        HashSet<AppWidgetAttribute> set = null;
+        // 如果c不为空
+        if (c != null) {
+            // 如果c可以移动到下一行
+            if (c.moveToFirst()) {
+                // 创建一个新的HashSet
+                set = new HashSet<AppWidgetAttribute>();
+                // 循环遍历c中的每一行
+                do {
+                    try {
+                        // 创建一个新的AppWidgetAttribute对象
+                        AppWidgetAttribute widget = new AppWidgetAttribute();
+                        // 获取widgetId的值
+                        widget.widgetId = c.getInt(0);
+                        // 获取widgetType的值
+                        widget.widgetType = c.getInt(1);
+                        // 将widget添加到set中
+                        set.add(widget);
+                    } catch (IndexOutOfBoundsException e) {
+                        // 如果发生IndexOutOfBoundsException异常，打印错误日志
+                        Log.e(TAG, e.toString());
+                    }
+                } while (c.moveToNext());
+            }
+            // 关闭c
+            c.close();
+        }
+        // 返回set
+        return set;
+    }
+
+    public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
+        // 根据noteId查询CallNote表中的PHONE_NUMBER字段
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.PHONE_NUMBER },
+                CallNote.NOTE_ID + "=? AND " + CallNote.MIME_TYPE + "=?",
+                new String [] { String.valueOf(noteId), CallNote.CONTENT_ITEM_TYPE },
+                null);
+
+        // 如果查询结果不为空且游标指向第一条数据
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                // 返回PHONE_NUMBER字段的值
+                return cursor.getString(0);
+            } catch (IndexOutOfBoundsException e) {
+                // 如果发生IndexOutOfBoundsException异常，打印错误日志
+                Log.e(TAG, "Get call number fails " + e.toString());
+            } finally {
+                // 关闭游标
+                cursor.close();
+            }
+        }
+        // 如果查询结果为空，返回空字符串
+        return "";
+    }
+
+    public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
+        // 根据电话号码和通话日期查询笔记ID
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                // 查询的列
+                new String [] { CallNote.NOTE_ID },
+                // 查询的条件
+                CallNote.CALL_DATE + "=? AND " + CallNote.MIME_TYPE + "=? AND PHONE_NUMBERS_EQUAL("
+                + CallNote.PHONE_NUMBER + ",?)",
+                // 查询的参数
+                new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
+                null);
+
+        // 判断cursor是否为空
+        if (cursor != null) {
+            // 将cursor移动到第一行
+            if (cursor.moveToFirst()) {
+                try {
+                    // 返回cursor中第一列的值
+                    return cursor.getLong(0);
+                } catch (IndexOutOfBoundsException e) {
+                    // 如果发生IndexOutOfBoundsException异常，打印错误日志
+                    Log.e(TAG, "Get call note id fails " + e.toString());
+                }
+            }
+            // 关闭cursor
+            cursor.close();
+        }
+        // 如果cursor为空，返回0
+        return 0;
+    }
+
+    public static String getSnippetById(ContentResolver resolver, long noteId) {
+        // 通过ContentResolver查询指定id的note的snippet
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
+  // 创建一个包含NoteColumns.SNIPPET的字符串数组
+                new String [] { NoteColumns.SNIPPET },
+                NoteColumns.ID + "=?",
+ // 创建一个包含noteId的字符串数组
+                new String [] { String.valueOf(noteId)},
+                null);
+
+// 判断cursor是否为空
+        if (cursor != null) {
+            // 定义一个字符串变量snippet，用于存储从cursor中获取的字符串
+            String snippet = "";
+            // 将cursor移动到第一行
+            if (cursor.moveToFirst()) {
+                // 从cursor中获取第一列的字符串，并赋值给snippet
+                snippet = cursor.getString(0);
+            }
+ // 关闭游标
+            cursor.close();
+ // 返回片段
+            return snippet;
+        }
+ // 抛出异常，提示找不到指定id的笔记
+        throw new IllegalArgumentException("Note is not found with id: " + noteId);
+    }
+
+    // 格式化snippet
+    public static String getFormattedSnippet(String snippet) {
+        // 如果snippet不为空
+        if (snippet != null) {
+            // 去除snippet两端的空格
+            snippet = snippet.trim();
+            // 获取snippet中第一个换行符的位置
+            int index = snippet.indexOf('\n');
+            // 如果存在换行符
+            if (index != -1) {
+                // 截取换行符之前的内容
+                snippet = snippet.substring(0, index);
+            }
+        }
+        // 返回格式化后的snippet
+        return snippet;
+    }
+}

src/tool/GTaskStringUtils.java

@@ -0,0 +1,157 @@
+/*
+ * 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.tool;
+
+public class GTaskStringUtils {
+
+    // 定义GTask JSON中的action_id字段
+    public final static String GTASK_JSON_ACTION_ID = "action_id";
+
+    // 定义GTask JSON中的action_list字段
+    public final static String GTASK_JSON_ACTION_LIST = "action_list";
+
+    // 定义GTask JSON中的action_type字段
+    public final static String GTASK_JSON_ACTION_TYPE = "action_type";
+
+    // 定义GTask JSON中的action_type字段，表示创建操作
+    public final static String GTASK_JSON_ACTION_TYPE_CREATE = "create";
+
+    // 定义GTask JSON中的action_type字段，表示获取所有操作
+    public final static String GTASK_JSON_ACTION_TYPE_GETALL = "get_all";
+
+    // 定义任务JSON操作类型为移动
+    public final static String GTASK_JSON_ACTION_TYPE_MOVE = "move";
+
+    // 定义任务JSON操作类型为更新
+    public final static String GTASK_JSON_ACTION_TYPE_UPDATE = "update";
+
+    // 定义任务JSON创建者ID
+    public final static String GTASK_JSON_CREATOR_ID = "creator_id";
+
+    // 定义任务JSON子实体
+    public final static String GTASK_JSON_CHILD_ENTITY = "child_entity";
+
+    // 定义任务JSON客户端版本
+    public final static String GTASK_JSON_CLIENT_VERSION = "client_version";
+
+    // 定义任务JSON是否完成
+    public final static String GTASK_JSON_COMPLETED = "completed";
+
+    // 定义任务JSON当前列表ID
+    public final static String GTASK_JSON_CURRENT_LIST_ID = "current_list_id";
+
+    // 定义任务JSON默认列表ID
+    public final static String GTASK_JSON_DEFAULT_LIST_ID = "default_list_id";
+
+    // 定义任务JSON是否删除
+    public final static String GTASK_JSON_DELETED = "deleted";
+
+    // 定义任务JSON目标列表
+    public final static String GTASK_JSON_DEST_LIST = "dest_list";
+
+    // 定义任务JSON目标父级
+    public final static String GTASK_JSON_DEST_PARENT = "dest_parent";
+
+    public final static String GTASK_JSON_DEST_PARENT_TYPE = "dest_parent_type";
+
+    // 实体增量
+    public final static String GTASK_JSON_ENTITY_DELTA = "entity_delta";
+
+    // 实体类型
+    public final static String GTASK_JSON_ENTITY_TYPE = "entity_type";
+
+    // 获取已删除
+    public final static String GTASK_JSON_GET_DELETED = "get_deleted";
+
+    // ID
+    public final static String GTASK_JSON_ID = "id";
+
+    // 索引
+    public final static String GTASK_JSON_INDEX = "index";
+
+    // 最后修改时间
+    public final static String GTASK_JSON_LAST_MODIFIED = "last_modified";
+
+    // 最新同步点
+    public final static String GTASK_JSON_LATEST_SYNC_POINT = "latest_sync_point";
+
+    // 列表ID
+    public final static String GTASK_JSON_LIST_ID = "list_id";
+
+    // 列表
+    public final static String GTASK_JSON_LISTS = "lists";
+
+    // 名称
+    public final static String GTASK_JSON_NAME = "name";
+
+    // 新ID
+    public final static String GTASK_JSON_NEW_ID = "new_id";
+
+    // 备注
+    public final static String GTASK_JSON_NOTES = "notes";
+
+    // 父ID
+    public final static String GTASK_JSON_PARENT_ID = "parent_id";
+
+    // 前一个兄弟ID
+    public final static String GTASK_JSON_PRIOR_SIBLING_ID = "prior_sibling_id";
+
+    // 结果
+    public final static String GTASK_JSON_RESULTS = "results";
+
+    // 源列表
+    public final static String GTASK_JSON_SOURCE_LIST = "source_list";
+
+    public final static String GTASK_JSON_TASKS = "tasks";
+
+    // 任务类型
+    public final static String GTASK_JSON_TYPE = "type";
+
+    // 任务组
+    public final static String GTASK_JSON_TYPE_GROUP = "GROUP";
+
+    // 任务
+    public final static String GTASK_JSON_TYPE_TASK = "TASK";
+
+    // 用户
+    public final static String GTASK_JSON_USER = "user";
+
+    // MIUI文件夹前缀
+    public final static String MIUI_FOLDER_PREFFIX = "[MIUI_Notes]";
+
+    // 默认文件夹
+    public final static String FOLDER_DEFAULT = "Default";
+
+    // 呼叫记录文件夹
+    public final static String FOLDER_CALL_NOTE = "Call_Note";
+
+    // 元数据文件夹
+    public final static String FOLDER_META = "METADATA";
+
+    // 元数据任务ID
+    public final static String META_HEAD_GTASK_ID = "meta_gid";
+
+    // 元数据笔记
+    public final static String META_HEAD_NOTE = "meta_note";
+
+    // 元数据数据
+    public final static String META_HEAD_DATA = "meta_data";
+
+    // 元数据笔记名称
+    public final static String META_NOTE_NAME = "[META INFO] DON'T UPDATE AND DELETE";
+
+}

src/tool/ResourceParser.java

@@ -0,0 +1,219 @@
+/*
+ * 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.tool;
+
+import android.content.Context;
+import android.preference.PreferenceManager;
+
+import net.micode.notes.R;
+import net.micode.notes.ui.NotesPreferenceActivity;
+
+public class ResourceParser {
+
+    // 定义颜色常量
+    public static final int YELLOW           = 0;
+    public static final int BLUE             = 1;
+    public static final int WHITE            = 2;
+    public static final int GREEN            = 3;
+    public static final int RED              = 4;
+
+    // 定义默认背景颜色
+    public static final int BG_DEFAULT_COLOR = YELLOW;
+
+    // 定义字体大小常量
+    public static final int TEXT_SMALL       = 0;
+    public static final int TEXT_MEDIUM      = 1;
+    public static final int TEXT_LARGE       = 2;
+    public static final int TEXT_SUPER       = 3;
+
+    // 定义默认字体大小
+    public static final int BG_DEFAULT_FONT_SIZE = TEXT_MEDIUM;
+
+    public static class NoteBgResources {
+        // 定义一个静态的整型数组，用于存储背景图片的资源ID
+        private final static int [] BG_EDIT_RESOURCES = new int [] {
+            // 背景图片资源ID
+            R.drawable.edit_yellow,
+            R.drawable.edit_blue,
+            R.drawable.edit_white,
+            R.drawable.edit_green,
+            R.drawable.edit_red
+        };
+
+// 定义一个常量数组，用于存储编辑标题的背景资源
+        private final static int [] BG_EDIT_TITLE_RESOURCES = new int [] {
+            // 黄色背景
+            R.drawable.edit_title_yellow,
+            // 蓝色背景
+            R.drawable.edit_title_blue,
+            // 白色背景
+            R.drawable.edit_title_white,
+            // 绿色背景
+            R.drawable.edit_title_green,
+            // 红色背景
+            R.drawable.edit_title_red
+        };
+
+        public static int getNoteBgResource(int id) {
+            // 根据id返回对应的背景资源
+            return BG_EDIT_RESOURCES[id];
+        }
+
+        public static int getNoteTitleBgResource(int id) {
+            return BG_EDIT_TITLE_RESOURCES[id];
+        }
+    }
+
+    public static int getDefaultBgId(Context context) {
+        // 获取默认的背景颜色
+        if (PreferenceManager.getDefaultSharedPreferences(context).getBoolean(
+                NotesPreferenceActivity.PREFERENCE_SET_BG_COLOR_KEY, false)) {
+            // 如果设置了背景颜色，则返回一个随机的背景颜色
+            return (int) (Math.random() * NoteBgResources.BG_EDIT_RESOURCES.length);
+        } else {
+            // 如果没有设置背景颜色，则返回默认的背景颜色
+            return BG_DEFAULT_COLOR;
+        }
+    }
+
+    public static class NoteItemBgResources {
+        // 定义一个静态的整型数组，用于存储背景图片的资源ID
+        private final static int [] BG_FIRST_RESOURCES = new int [] {
+            // 黄色背景图片的资源ID
+            R.drawable.list_yellow_up,
+            // 蓝色背景图片的资源ID
+            R.drawable.list_blue_up,
+            // 白色背景图片的资源ID
+            R.drawable.list_white_up,
+            // 绿色背景图片的资源ID
+            R.drawable.list_green_up,
+            // 红色背景图片的资源ID
+            R.drawable.list_red_up
+        };
+
+        private final static int [] BG_NORMAL_RESOURCES = new int [] {
+            R.drawable.list_yellow_middle, // 黄色背景
+            R.drawable.list_blue_middle, // 蓝色背景
+            R.drawable.list_white_middle, // 白色背景
+            R.drawable.list_green_middle, // 绿色背景
+            R.drawable.list_red_middle // 红色背景
+        };
+
+        private final static int [] BG_LAST_RESOURCES = new int [] {
+            R.drawable.list_yellow_down, // 黄色背景
+            R.drawable.list_blue_down, // 蓝色背景
+            R.drawable.list_white_down, // 白色背景
+            R.drawable.list_green_down, // 绿色背景
+            R.drawable.list_red_down, // 红色背景
+        };
+
+        private final static int [] BG_SINGLE_RESOURCES = new int [] {
+            R.drawable.list_yellow_single, // 黄色背景
+            R.drawable.list_blue_single, // 蓝色背景
+            R.drawable.list_white_single, // 白色背景
+            R.drawable.list_green_single, // 绿色背景
+            R.drawable.list_red_single // 红色背景
+        };
+
+        // 获取笔记背景的第一张图片
+        public static int getNoteBgFirstRes(int id) {
+            return BG_FIRST_RESOURCES[id];
+        }
+
+        // 获取笔记背景的最后一张图片
+        public static int getNoteBgLastRes(int id) {
+            return BG_LAST_RESOURCES[id];
+        }
+
+        // 获取笔记背景的单张图片
+        public static int getNoteBgSingleRes(int id) {
+            return BG_SINGLE_RESOURCES[id];
+        }
+
+        // 获取笔记背景的正常图片
+        public static int getNoteBgNormalRes(int id) {
+            return BG_NORMAL_RESOURCES[id];
+        }
+
+        // 获取文件夹背景的图片
+        public static int getFolderBgRes() {
+            return R.drawable.list_folder;
+        }
+    }
+
+    public static class WidgetBgResources {
+        // 定义一个静态的整数数组，用于存储2x分辨率的背景资源
+        private final static int [] BG_2X_RESOURCES = new int [] {
+            R.drawable.widget_2x_yellow, // 2x分辨率的黄色背景资源
+            R.drawable.widget_2x_blue, // 2x分辨率的蓝色背景资源
+            R.drawable.widget_2x_white, // 2x分辨率的白色背景资源
+            R.drawable.widget_2x_green, // 2x分辨率的绿色背景资源
+            R.drawable.widget_2x_red, // 2x分辨率的红色背景资源
+        };
+
+        public static int getWidget2xBgResource(int id) {
+            // 根据id返回对应的2x背景资源
+            return BG_2X_RESOURCES[id];
+        }
+
+        // 定义4x背景资源数组
+        private final static int [] BG_4X_RESOURCES = new int [] {
+            R.drawable.widget_4x_yellow,
+            R.drawable.widget_4x_blue,
+            R.drawable.widget_4x_white,
+            R.drawable.widget_4x_green,
+            R.drawable.widget_4x_red
+        };
+
+        // 根据id返回对应的4x背景资源
+        public static int getWidget4xBgResource(int id) {
+            return BG_4X_RESOURCES[id];
+        }
+    }
+
+    // 定义文本样式资源类
+    public static class TextAppearanceResources {
+        // 定义文本样式资源数组
+        private final static int [] TEXTAPPEARANCE_RESOURCES = new int [] {
+            R.style.TextAppearanceNormal,
+            R.style.TextAppearanceMedium,
+            R.style.TextAppearanceLarge,
+            R.style.TextAppearanceSuper
+        };
+
+// 根据id获取文本外观资源
+        public static int getTexAppearanceResource(int id) {
+            /**
+             * HACKME: Fix bug of store the resource id in shared preference.
+             * The id may larger than the length of resources, in this case,
+             * return the {@link ResourceParser#BG_DEFAULT_FONT_SIZE}
+             */
+// 判断id是否大于等于TEXTAPPEARANCE_RESOURCES的长度
+            if (id >= TEXTAPPEARANCE_RESOURCES.length) {
+                // 如果是，则返回默认字体大小
+                return BG_DEFAULT_FONT_SIZE;
+            }
+            // 否则，返回TEXTAPPEARANCE_RESOURCES中对应id的值
+            return TEXTAPPEARANCE_RESOURCES[id];
+        }
+
+        // 获取TEXTAPPEARANCE_RESOURCES的长度
+        public static int getResourcesSize() {
+            return TEXTAPPEARANCE_RESOURCES.length;
+        }
+    }
+}