在原有基础上增加注释，添加了文件夹功能

NotesMaster2/app/src/main/java/net/micode/notes/data/Contact.java

@@ -0,0 +1,87 @@
+/*
+ * 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
+    // 定义一个常量，用于选择来电号码
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
+            // 选择来电号码等于参数
+            + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+            // 选择MIME类型为Phone.CONTENT_ITEM_TYPE
+            + " AND " + Data.RAW_CONTACT_ID + " IN "
+            // 选择RAW_CONTACT_ID在phone_lookup表中min_match为+的记录中
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+
+    public static String getContact(Context context, String phoneNumber) {
+        // 如果sContactCache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，则直接返回对应的联系人名称
+        if(sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 构造查询条件，将phoneNumber中的"+"替换为PhoneNumberUtils.toCallerIDMinMatch(phoneNumber)的返回值
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+        // 查询联系人数据库，获取联系人名称
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,
+                new String [] { Phone.DISPLAY_NAME },
+                selection,
+                new String[] { phoneNumber },
+                null);
+
+        // 如果查询结果不为空，则获取联系人名称，并放入sContactCache中
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                String name = cursor.getString(0);
+                sContactCache.put(phoneNumber, name);
+                return name;
+            } catch (IndexOutOfBoundsException e) {
+                // 如果获取联系人名称出错，则打印错误日志
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                // 关闭查询结果
+                cursor.close();
+            }
+        } else {
+            // 如果没有匹配的联系人，则打印日志
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}

NotesMaster2/app/src/main/java/net/micode/notes/data/Notes.java

@@ -0,0 +1,304 @@
+/*
+ * 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类的常量
+    // 定义一个常量，表示Notes的授权
+    public static final String AUTHORITY = "micode_notes";
+    // 定义一个常量，表示Notes的标签
+    public static final String TAG = "Notes";
+    // 定义一个常量，表示Notes的类型为Note
+    public static final int TYPE_NOTE     = 0;
+    // 定义一个常量，表示Notes的类型为Folder
+    public static final int TYPE_FOLDER   = 1;
+    // 定义一个常量，表示Notes的类型为System
+    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
+     */
+    // 根文件夹的ID
+    public static final int ID_ROOT_FOLDER = 0;
+    // 临时文件夹的ID
+    public static final int ID_TEMPARAY_FOLDER = -1;
+    // 呼叫记录文件夹的ID
+    public static final int ID_CALL_RECORD_FOLDER = -2;
+    // 回收站文件夹的ID
+    public static final int ID_TRASH_FOLER = -3;
+
+    // 定义Intent的额外参数
+    public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date";
+    public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id";
+    public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id";
+    public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type";
+    public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id";
+    public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date";
+
+    // 定义Widget的类型
+    public static final int TYPE_WIDGET_INVALIDE      = -1;
+    public static final int TYPE_WIDGET_2X            = 0;
+    public static final int TYPE_WIDGET_4X            = 1;
+
+    // 定义DataConstants类
+    public static class DataConstants {
+        public static final String NOTE = TextNote.CONTENT_ITEM_TYPE;
+        public static final String CALL_NOTE = CallNote.CONTENT_ITEM_TYPE;
+    }
+
+    /**
+     * Uri to query all notes and folders
+     */
+    public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note");
+
+    /**
+     * Uri to query data
+     */
+    public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data");
+
+    // 定义NoteColumns接口
+    public interface NoteColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The parent's id for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String PARENT_ID = "parent_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+
+        /**
+         * Alert date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ALERTED_DATE = "alert_date";
+
+        /**
+         * Folder's name or text content of note
+         * <P> Type: TEXT </P>
+         */
+        public static final String SNIPPET = "snippet";
+
+        /**
+         * Note's widget id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_ID = "widget_id";
+
+        /**
+         * Note's widget type
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String WIDGET_TYPE = "widget_type";
+
+        /**
+         * Note's background color's id
+         * <P> Type: INTEGER (long) </P>
+         */
+        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>
+         */
+        public static final String HAS_ATTACHMENT = "has_attachment";
+
+        /**
+         * Folder's count of notes
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTES_COUNT = "notes_count";
+
+        /**
+         * The file type: folder or note
+         * <P> Type: INTEGER </P>
+         */
+        public static final String TYPE = "type";
+
+        /**
+         * The last sync id
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String SYNC_ID = "sync_id";
+
+        /**
+         * Sign to indicate local modified or not
+         * <P> Type: INTEGER </P>
+         */
+        public static final String LOCAL_MODIFIED = "local_modified";
+
+        /**
+         * Original parent id before moving into temporary folder
+         * <P> Type : INTEGER </P>
+         */
+        public static final String ORIGIN_PARENT_ID = "origin_parent_id";
+
+        /**
+         * The gtask id
+         * <P> Type : TEXT </P>
+         */
+        public static final String GTASK_ID = "gtask_id";
+
+        /**
+         * The version code
+         * <P> Type : INTEGER (long) </P>
+         */
+        public static final String VERSION = "version";
+    }
+
+    // 定义DataColumns接口
+    public interface DataColumns {
+        /**
+         * The unique ID for a row
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String ID = "_id";
+
+        /**
+         * The MIME type of the item represented by this row.
+         * <P> Type: Text </P>
+         */
+        public static final String MIME_TYPE = "mime_type";
+
+        /**
+         * The reference id to note that this data belongs to
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String NOTE_ID = "note_id";
+
+        /**
+         * Created data for note or folder
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String CREATED_DATE = "created_date";
+
+        /**
+         * Latest modified date
+         * <P> Type: INTEGER (long) </P>
+         */
+        public static final String MODIFIED_DATE = "modified_date";
+
+        /**
+         * Data's content
+         * <P> Type: TEXT </P>
+         */
+        public static final String CONTENT = "content";
+
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA1 = "data1";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * integer data type
+         * <P> Type: INTEGER </P>
+         */
+        public static final String DATA2 = "data2";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA3 = "data3";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA4 = "data4";
+
+        /**
+         * Generic data column, the meaning is {@link #MIMETYPE} specific, used for
+         * TEXT data type
+         * <P> Type: TEXT </P>
+         */
+        public static final String DATA5 = "data5";
+    }
+
+    // 定义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;
+
+        // 检查列表模式
+        public static final int MODE_CHECK_LIST = 1;
+
+        // 内容类型
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+        // 内容项类型
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        // 内容URI
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }
+
+    // 定义CallNote类
+    public static final class CallNote implements DataColumns {
+        /**
+         * Call date for this record
+         * <P> Type: INTEGER (long) </P>
+         */
+        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");
+    }
+}

NotesMaster2/app/src/main/java/net/micode/notes/data/NotesDatabaseHelper.java

@@ -0,0 +1,466 @@
+/*
+ * 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;
+
+    // 定义数据库中的表名
+    public interface TABLE {
+        // 表名：note
+        public static final String NOTE = "note";
+
+        // 表名：data
+        public static final String DATA = "data";
+    }
+
+    // 定义一个常量，用于标识数据库帮助类的标签
+    private static final String TAG = "NotesDatabaseHelper";
+
+    // 定义一个静态变量，用于保存数据库帮助类的实例
+    private static NotesDatabaseHelper mInstance;
+
+    // 定义一个常量，用于保存创建笔记表的SQL语句
+    private static final String CREATE_NOTE_TABLE_SQL =
+            "CREATE TABLE " + TABLE.NOTE + "(" +
+                    // 定义笔记表的ID列，类型为INTEGER，为主键
+                    NoteColumns.ID + " INTEGER PRIMARY KEY," +
+                    // 定义笔记表的父ID列，类型为INTEGER，默认值为0
+                    NoteColumns.PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的提醒日期列，类型为INTEGER，默认值为0
+                    NoteColumns.ALERTED_DATE + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的背景颜色ID列，类型为INTEGER，默认值为0
+                    NoteColumns.BG_COLOR_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的创建日期列，类型为INTEGER，默认值为当前时间戳
+                    NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+                    // 定义笔记表是否有附件列，类型为INTEGER，默认值为0
+                    NoteColumns.HAS_ATTACHMENT + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的修改日期列，类型为INTEGER，默认值为当前时间戳
+                    NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+                    // 定义笔记表的笔记数量列，类型为INTEGER，默认值为0
+                    NoteColumns.NOTES_COUNT + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的摘要列，类型为TEXT，默认值为空字符串
+                    NoteColumns.SNIPPET + " TEXT NOT NULL DEFAULT ''," +
+                    // 定义笔记表的类型列，类型为INTEGER，默认值为0
+                    NoteColumns.TYPE + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的Widget ID列，类型为INTEGER，默认值为0
+                    NoteColumns.WIDGET_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的Widget类型列，类型为INTEGER，默认值为-1
+                    NoteColumns.WIDGET_TYPE + " INTEGER NOT NULL DEFAULT -1," +
+                    // 定义笔记表的同步ID列，类型为INTEGER，默认值为0
+                    NoteColumns.SYNC_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的本地修改列，类型为INTEGER，默认值为0
+                    NoteColumns.LOCAL_MODIFIED + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的原始父ID列，类型为INTEGER，默认值为0
+                    NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义笔记表的GTask ID列，类型为TEXT，默认值为空字符串
+                    NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," +
+                    // 定义笔记表的版本列，类型为INTEGER，默认值为0
+                    NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" +
+                    ")";
+
+    // 定义创建数据表的SQL语句
+    private static final String CREATE_DATA_TABLE_SQL =
+            "CREATE TABLE " + TABLE.DATA + "(" +
+                    // 定义ID列，类型为INTEGER，为主键
+                    DataColumns.ID + " INTEGER PRIMARY KEY," +
+                    // 定义MIME_TYPE列，类型为TEXT，不能为空
+                    DataColumns.MIME_TYPE + " TEXT NOT NULL," +
+                    // 定义NOTE_ID列，类型为INTEGER，不能为空，默认值为0
+                    DataColumns.NOTE_ID + " INTEGER NOT NULL DEFAULT 0," +
+                    // 定义CREATED_DATE列，类型为INTEGER，不能为空，默认值为当前时间戳
+                    NoteColumns.CREATED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+                    // 定义MODIFIED_DATE列，类型为INTEGER，不能为空，默认值为当前时间戳
+                    NoteColumns.MODIFIED_DATE + " INTEGER NOT NULL DEFAULT (strftime('%s','now') * 1000)," +
+                    // 定义CONTENT列，类型为TEXT，不能为空，默认值为空字符串
+                    DataColumns.CONTENT + " TEXT NOT NULL DEFAULT ''," +
+                    // 定义DATA1列，类型为INTEGER
+                    DataColumns.DATA1 + " INTEGER," +
+                    // 定义DATA2列，类型为INTEGER
+                    DataColumns.DATA2 + " INTEGER," +
+                    // 定义DATA3列，类型为TEXT，不能为空，默认值为空字符串
+                    DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," +
+                    // 定义DATA4列，类型为TEXT，不能为空，默认值为空字符串
+                    DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," +
+                    // 定义DATA5列，类型为TEXT，不能为空，默认值为空字符串
+                    DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" +
+                    ")";
+
+    // 创建一个名为note_id_index的索引，用于在DATA表中根据NOTE_ID进行查询
+    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
+     */
+    // 创建一个名为increase_folder_count_on_update的触发器，用于在NOTE表中更新PARENT_ID时，增加对应文件夹的note count
+    // 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 =
+            "CREATE TRIGGER increase_folder_count_on_update "+
+                    " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+                    "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+                    " END";
+
+    /**
+     * Decrease folder's note count when move note from folder
+     */
+    // 创建一个触发器，在更新Note表的PARENT_ID字段后，减少对应文件夹的NOTES_COUNT字段
+    // 创建一个触发器，在更新Note表的PARENT_ID字段后，减少对应文件夹的NOTES_COUNT字段
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER =
+            "CREATE TRIGGER decrease_folder_count_on_update " +
+                    " AFTER UPDATE OF " + NoteColumns.PARENT_ID + " ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+                    "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+                    "  AND " + NoteColumns.NOTES_COUNT + ">0" + ";" +
+                    " END";
+
+    /**
+     * Increase folder's note count when insert new note to the folder
+     */
+    // 创建一个触发器，在插入笔记后，增加父文件夹的笔记数量
+    private static final String NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER =
+            "CREATE TRIGGER increase_folder_count_on_insert " +
+                    " AFTER INSERT ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" +
+                    "  WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" +
+                    " END";
+
+    /**
+     * Decrease folder's note count when delete note from the folder
+     */
+    // 创建一个触发器，在删除笔记后，减少父文件夹中的笔记数量
+    private static final String NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER decrease_folder_count_on_delete " +
+                    " AFTER DELETE ON " + TABLE.NOTE +
+                    " BEGIN " +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" +
+                    "  WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID +
+                    "  AND " + NoteColumns.NOTES_COUNT + ">0;" +
+                    " END";
+
+    /**
+     * Update note's content when insert data with type {@link DataConstants#NOTE}
+     */
+    // 创建一个触发器，在插入数据后更新笔记内容
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_insert " +
+                    " AFTER INSERT ON " + TABLE.DATA + // 在数据表上创建触发器
+                    " WHEN new." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" + // 当插入的数据类型为笔记时
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE + // 更新笔记表
+                    "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT + // 将新插入的数据内容设置为笔记的片段
+                    "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" + // 根据笔记ID更新笔记表
+                    " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has changed
+     */
+    // 创建一个名为update_note_content_on_update的触发器，在更新DATA表后执行
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_update " +
+                    " AFTER UPDATE ON " + TABLE.DATA +
+                    " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT +
+                    "  WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" +
+                    " END";
+
+    /**
+     * Update note's content when data with {@link DataConstants#NOTE} type has deleted
+     */
+    private static final String DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER =
+            "CREATE TRIGGER update_note_content_on_delete " +
+                    " AFTER delete ON " + TABLE.DATA +
+                    " WHEN old." + DataColumns.MIME_TYPE + "='" + DataConstants.NOTE + "'" +
+                    " BEGIN" +
+                    "  UPDATE " + TABLE.NOTE +
+                    "   SET " + NoteColumns.SNIPPET + "=''" +
+                    "  WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" +
+                    " END";
+
+    /**
+     * Delete datas belong to note which has been deleted
+     */
+    // 创建一个名为delete_data_on_delete的触发器，在删除note表中的数据后，删除data表中的数据
+    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
+     */
+    // 创建一个触发器，在删除笔记时，删除其子笔记
+    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
+     */
+    // 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，则更新NOTE表中的父ID为垃圾文件夹ID
+    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";
+
+    public NotesDatabaseHelper(Context context) {
+        super(context, DB_NAME, null, DB_VERSION);
+    }
+
+    /**
+     * 创建note表
+     */
+    public void createNoteTable(SQLiteDatabase db) {
+        // 执行创建note表的SQL语句
+        db.execSQL(CREATE_NOTE_TABLE_SQL);
+        // 重新创建note表的触发器
+        reCreateNoteTableTriggers(db);
+        // 创建系统文件夹
+        createSystemFolder(db);
+        // 打印日志，note表已创建
+        Log.d(TAG, "note table has been created");
+    }
+
+    /**
+     * 重新创建note表的触发器
+     */
+    // 重新创建Note表触发器
+    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");
+
+        // 创建increase_folder_count_on_update触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+        // 创建decrease_folder_count_on_update触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_UPDATE_TRIGGER);
+        // 创建decrease_folder_count_on_delete触发器
+        db.execSQL(NOTE_DECREASE_FOLDER_COUNT_ON_DELETE_TRIGGER);
+        // 创建delete_data_on_delete触发器
+        db.execSQL(NOTE_DELETE_DATA_ON_DELETE_TRIGGER);
+        // 创建increase_folder_count_on_insert触发器
+        db.execSQL(NOTE_INCREASE_FOLDER_COUNT_ON_INSERT_TRIGGER);
+        // 创建folder_delete_notes_on_delete触发器
+        db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER);
+        // 创建folder_move_notes_on_trash触发器
+        db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER);
+    }
+
+    /**
+     * 创建系统文件夹
+     */
+    // 创建系统文件夹
+    private void createSystemFolder(SQLiteDatabase db) {
+        ContentValues values = new ContentValues();
+
+
+        // 插入通话记录文件夹
+        values.put(NoteColumns.ID, Notes.ID_CALL_RECORD_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+
+        // 清空values
+        values.clear();
+        // 插入根文件夹
+        values.put(NoteColumns.ID, Notes.ID_ROOT_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * temporary folder which is used for moving note
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TEMPARAY_FOLDER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+
+        /**
+         * create trash folder
+         */
+        values.clear();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /**
+     * 创建data表
+     */
+    public void createDataTable(SQLiteDatabase db) {
+        db.execSQL(CREATE_DATA_TABLE_SQL);
+        reCreateDataTableTriggers(db);
+        db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL);
+        Log.d(TAG, "data table has been created");
+    }
+
+    /**
+     * 重新创建data表的触发器
+     */
+    private void reCreateDataTableTriggers(SQLiteDatabase db) {
+        // 删除原有的触发器
+        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
+     */
+    // 获取NotesDatabaseHelper实例
+    static synchronized NotesDatabaseHelper getInstance(Context context) {
+        // 如果mInstance为空，则创建一个新的NotesDatabaseHelper实例
+        if (mInstance == null) {
+            mInstance = new NotesDatabaseHelper(context);
+        }
+        // 返回mInstance
+        return mInstance;
+    }
+
+    // 创建数据库
+    @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是否跳过v2版本
+        boolean reCreateTriggers = false;
+        boolean skipV2 = false;
+
+        if (oldVersion == 1) {
+            upgradeToV2(db);
+            skipV2 = true; // this upgrade including the upgrade from v2 to v3
+            oldVersion++;
+        }
+
+        if (oldVersion == 2 && !skipV2) {
+            upgradeToV3(db);
+            reCreateTriggers = true;
+            oldVersion++;
+        }
+
+        if (oldVersion == 3) {
+            upgradeToV4(db);
+            oldVersion++;
+        }
+
+        if (reCreateTriggers) {
+            reCreateNoteTableTriggers(db);
+            reCreateDataTableTriggers(db);
+        }
+
+        if (oldVersion != newVersion) {
+            throw new IllegalStateException("Upgrade notes database to version " + newVersion
+                    + "fails");
+        }
+    }
+
+    /**
+     * 升级到v2版本
+     */
+    private void upgradeToV2(SQLiteDatabase db) {
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.NOTE);
+        db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA);
+        createNoteTable(db);
+        createDataTable(db);
+    }
+
+    /**
+     * 升级到v3版本
+     */
+    private void upgradeToV3(SQLiteDatabase db) {
+        // drop unused triggers
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_insert");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_delete");
+        db.execSQL("DROP TRIGGER IF EXISTS update_note_modified_date_on_update");
+        // add a column for gtask id
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.GTASK_ID
+                + " TEXT NOT NULL DEFAULT ''");
+        // add a trash system folder
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER);
+        values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM);
+        db.insert(TABLE.NOTE, null, values);
+    }
+
+    /**
+     * 升级到v4版本
+     */
+    private void upgradeToV4(SQLiteDatabase db) {
+        db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION
+                + " INTEGER NOT NULL DEFAULT 0");
+    }
+}

NotesMaster2/app/src/main/java/net/micode/notes/data/NotesProvider.java

@@ -0,0 +1,366 @@
+/*
+ * 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 {
+    private static final UriMatcher mMatcher;
+
+    private NotesDatabaseHelper mHelper;
+
+    // 定义TAG常量，用于日志输出
+    private static final String TAG = "NotesProvider";
+
+    // 定义URI常量，用于匹配URI
+    private static final int URI_NOTE            = 1;
+    private static final int URI_NOTE_ITEM       = 2;
+    private static final int URI_DATA            = 3;
+    private static final int URI_DATA_ITEM       = 4;
+
+    private static final int URI_SEARCH          = 5;
+    private static final int URI_SEARCH_SUGGEST  = 6;
+
+    // 静态代码块，初始化UriMatcher
+    static {
+        mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
+        mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
+        mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA);
+        mMatcher.addURI(Notes.AUTHORITY, "data/#", URI_DATA_ITEM);
+        mMatcher.addURI(Notes.AUTHORITY, "search", URI_SEARCH);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, URI_SEARCH_SUGGEST);
+        mMatcher.addURI(Notes.AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", URI_SEARCH_SUGGEST);
+    }
+
+    /**
+     * 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.
+     */
+    // 定义搜索结果的投影
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+            // 搜索结果的ID
+            + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+            // 搜索结果的文本1
+            + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+            // 搜索结果的文本2
+            + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+            // 搜索结果的图标
+            + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+            // 搜索结果的Intent Action
+            + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+            // 搜索结果的Intent Data
+            + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+
+    // 定义一个静态字符串，用于查询笔记片段
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+            + " FROM " + TABLE.NOTE
+            + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+            + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+            + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    // 创建数据库
+    @Override
+    public boolean onCreate() {
+        // 获取NotesDatabaseHelper实例
+        mHelper = NotesDatabaseHelper.getInstance(getContext());
+        return true;
+    }
+
+    @Override
+    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
+                        String sortOrder) {
+        Cursor c = null;
+        SQLiteDatabase db = mHelper.getReadableDatabase();
+        String id = null;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.NOTE, projection, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_DATA:
+                c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                c = db.query(TABLE.DATA, projection, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs, null, null, sortOrder);
+                break;
+            case URI_SEARCH:
+            case URI_SEARCH_SUGGEST:
+                if (sortOrder != null || projection != null) {
+                    throw new IllegalArgumentException(
+                            "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
+                }
+
+                String searchString = null;
+                if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
+                    if (uri.getPathSegments().size() > 1) {
+                        searchString = uri.getPathSegments().get(1);
+                    }
+                } else {
+                    searchString = uri.getQueryParameter("pattern");
+                }
+
+                if (TextUtils.isEmpty(searchString)) {
+                    return null;
+                }
+
+                try {
+                    searchString = String.format("%%%s%%", searchString);
+                    c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
+                            new String[] { searchString });
+                } catch (IllegalStateException ex) {
+                    Log.e(TAG, "got exception: " + ex.toString());
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        if (c != null) {
+            c.setNotificationUri(getContext().getContentResolver(), uri);
+        }
+        return c;
+    }
+
+    @Override
+    public Uri insert(Uri uri, ContentValues values) {
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        long dataId = 0, noteId = 0, insertedId = 0;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                insertedId = noteId = db.insert(TABLE.NOTE, null, values);
+                break;
+            case URI_DATA:
+                if (values.containsKey(DataColumns.NOTE_ID)) {
+                    noteId = values.getAsLong(DataColumns.NOTE_ID);
+                } else {
+                    Log.d(TAG, "Wrong data format without note id:" + values.toString());
+                }
+                insertedId = dataId = db.insert(TABLE.DATA, null, values);
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // Notify the note uri
+        if (noteId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
+        }
+
+        // Notify the data uri
+        if (dataId > 0) {
+            getContext().getContentResolver().notifyChange(
+                    ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
+        }
+
+        return ContentUris.withAppendedId(uri, insertedId);
+    }
+
+    @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匹配对应的操作
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 添加删除条件
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
+                // 删除符合条件的记录
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                // 获取URI中的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
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                // 删除所有data
+                count = db.delete(TABLE.DATA, selection, selectionArgs);
+                // 标记删除data
+                deleteData = true;
+                break;
+            case URI_DATA_ITEM:
+                // 获取uri的路径段，获取第二个路径段作为id
+                id = uri.getPathSegments().get(1);
+                // 删除指定id的data
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                // 标记删除data
+                deleteData = true;
+                break;
+            default:
+                // 抛出异常，未知uri
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // 如果删除了数据
+        if (count > 0) {
+            // 如果删除了data，则通知content resolver
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            // 通知content resolver
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        // 返回删除的条数
+        return count;
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        // 定义更新条数
+        int count = 0;
+        // 定义id
+        String id = null;
+        // 获取可写数据库
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        // 定义是否更新数据
+        boolean updateData = false;
+        // 根据uri匹配对应的操作
+        switch (mMatcher.match(uri)) {
+            // 更新note表
+            case URI_NOTE:
+                // 增加note版本号
+                increaseNoteVersion(-1, selection, selectionArgs);
+                // 更新数据
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
+                break;
+            // 更新note_item表
+            case URI_NOTE_ITEM:
+                // 获取id
+                id = uri.getPathSegments().get(1);
+                // 增加note版本号
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
+                // 更新数据
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                break;
+            // 更新data表
+            case URI_DATA:
+                // 更新数据
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);
+                // 标记更新数据
+                updateData = true;
+                break;
+            // 更新data_item表
+            case URI_DATA_ITEM:
+                // 获取id
+                id = uri.getPathSegments().get(1);
+                // 更新数据
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                // 标记更新数据
+                updateData = true;
+                break;
+            // 未知uri
+            default:
+                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，Notes.CONTENT_NOTE_URI发生了变化
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            // 通知ContentResolver，uri发生了变化
+            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，则返回" AND (" + selection + ')'，否则返回空字符串
+        return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
+    }
+
+    private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
+        StringBuilder sql = new StringBuilder(120);
+        sql.append("UPDATE ");
+        sql.append(TABLE.NOTE);
+        sql.append(" SET ");
+        sql.append(NoteColumns.VERSION);
+        sql.append("=" + NoteColumns.VERSION + "+1 ");
+
+        if (id > 0 || !TextUtils.isEmpty(selection)) {
+            sql.append(" WHERE ");
+        }
+        if (id > 0) {
+            sql.append(NoteColumns.ID + "=" + String.valueOf(id));
+        }
+        if (!TextUtils.isEmpty(selection)) {
+            String selectString = id > 0 ? parseSelection(selection) : selection;
+            for (String args : selectionArgs) {
+                selectString = selectString.replaceFirst("\\?", args);
+            }
+            sql.append(selectString);
+        }
+
+        mHelper.getWritableDatabase().execSQL(sql.toString());
+    }
+
+    @Override
+    public String getType(Uri uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}