diff --git a/src/DataUtils.java b/src/DataUtils.java
new file mode 100644
index 0000000..f972635
--- /dev/null
+++ b/src/DataUtils.java
@@ -0,0 +1,295 @@
+/*
+ * 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;
+
+// 该类提供了一系列与便签数据操作相关的工具方法
+// 包含数据库查询、数据转换等通用操作，方便其他类调用
+public class DataUtils {
+    public static final String TAG = "DataUtils";
+    public static boolean batchDeleteNotes(ContentResolver resolver, HashSet<Long> ids) {
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+        if (ids.size() == 0) {
+            Log.d(TAG, "no id is in the hashset");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+        for (long id : ids) {
+            if(id == Notes.ID_ROOT_FOLDER) {
+                Log.e(TAG, "Don't delete system folder root");
+                continue;
+            }
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newDelete(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+            operationList.add(builder.build());
+        }
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+    public static void moveNoteToFoler(ContentResolver resolver, long id, long srcFolderId, long desFolderId) {
+        ContentValues values = new ContentValues();
+        values.put(NoteColumns.PARENT_ID, desFolderId);
+        values.put(NoteColumns.ORIGIN_PARENT_ID, srcFolderId);
+        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+        resolver.update(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id), values, null, null);
+    }
+    // 批量移动便签到指定文件夹
+    public static boolean batchMoveToFolder(ContentResolver resolver, HashSet<Long> ids,
+            long folderId) {
+        if (ids == null) {
+            Log.d(TAG, "the ids is null");
+            return true;
+        }
+
+        ArrayList<ContentProviderOperation> operationList = new ArrayList<ContentProviderOperation>();
+        for (long id : ids) {
+            ContentProviderOperation.Builder builder = ContentProviderOperation
+                    .newUpdate(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, id));
+            builder.withValue(NoteColumns.PARENT_ID, folderId);
+            builder.withValue(NoteColumns.LOCAL_MODIFIED, 1);
+            operationList.add(builder.build());
+        }
+
+        try {
+            ContentProviderResult[] results = resolver.applyBatch(Notes.AUTHORITY, operationList);
+            if (results == null || results.length == 0 || results[0] == null) {
+                Log.d(TAG, "delete notes failed, ids:" + ids.toString());
+                return false;
+            }
+            return true;
+        } catch (RemoteException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        } catch (OperationApplicationException e) {
+            Log.e(TAG, String.format("%s: %s", e.toString(), e.getMessage()));
+        }
+        return false;
+    }
+
+    /**
+     * Get the all folder count except system folders {@link Notes#TYPE_SYSTEM}}
+     */
+    public static int getUserFolderCount(ContentResolver resolver) {
+        Cursor cursor =resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { "COUNT(*)" },
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>?",
+                new String[] { String.valueOf(Notes.TYPE_FOLDER), String.valueOf(Notes.ID_TRASH_FOLER)},
+                null);
+
+        int count = 0;
+        if(cursor != null) {
+            if(cursor.moveToFirst()) {
+                try {
+                    count = cursor.getInt(0);
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "get folder count failed:" + e.toString());
+                } finally {
+                    cursor.close();
+                }
+            }
+        }
+        return count;
+    }
+
+    public static boolean visibleInNoteDatabase(ContentResolver resolver, long noteId, int type) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null,
+                NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER,
+                new String [] {String.valueOf(type)},
+                null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean existInNoteDatabase(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean existInDataDatabase(ContentResolver resolver, long dataId) {
+        Cursor cursor = resolver.query(ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId),
+                null, null, null, null);
+
+        boolean exist = false;
+        if (cursor != null) {
+            if (cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static boolean checkVisibleFolderName(ContentResolver resolver, String name) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI, null,
+                NoteColumns.TYPE + "=" + Notes.TYPE_FOLDER +
+                " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER +
+                " AND " + NoteColumns.SNIPPET + "=?",
+                new String[] { name }, null);
+        boolean exist = false;
+        if(cursor != null) {
+            if(cursor.getCount() > 0) {
+                exist = true;
+            }
+            cursor.close();
+        }
+        return exist;
+    }
+
+    public static HashSet<AppWidgetAttribute> getFolderNoteWidget(ContentResolver resolver, long folderId) {
+        Cursor c = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String[] { NoteColumns.WIDGET_ID, NoteColumns.WIDGET_TYPE },
+                NoteColumns.PARENT_ID + "=?",
+                new String[] { String.valueOf(folderId) },
+                null);
+
+        HashSet<AppWidgetAttribute> set = null;
+        if (c != null) {
+            if (c.moveToFirst()) {
+                set = new HashSet<AppWidgetAttribute>();
+                do {
+                    try {
+                        AppWidgetAttribute widget = new AppWidgetAttribute();
+                        widget.widgetId = c.getInt(0);
+                        widget.widgetType = c.getInt(1);
+                        set.add(widget);
+                    } catch (IndexOutOfBoundsException e) {
+                        Log.e(TAG, e.toString());
+                    }
+                } while (c.moveToNext());
+            }
+            c.close();
+        }
+        return set;
+    }
+
+    public static String getCallNumberByNoteId(ContentResolver resolver, long noteId) {
+        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);
+
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                return cursor.getString(0);
+            } catch (IndexOutOfBoundsException e) {
+                Log.e(TAG, "Get call number fails " + e.toString());
+            } finally {
+                cursor.close();
+            }
+        }
+        return "";
+    }
+
+    public static long getNoteIdByPhoneNumberAndCallDate(ContentResolver resolver, String phoneNumber, long callDate) {
+        Cursor cursor = resolver.query(Notes.CONTENT_DATA_URI,
+                new String [] { CallNote.NOTE_ID },
+                CallNote.CALL_DATE + "=? AND " + CallNote.MIME_TYPE + "=? AND PHONE_NUMBERS_EQUAL("
+                + CallNote.PHONE_NUMBER + ",?)",
+                new String [] { String.valueOf(callDate), CallNote.CONTENT_ITEM_TYPE, phoneNumber },
+                null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                try {
+                    return cursor.getLong(0);
+                } catch (IndexOutOfBoundsException e) {
+                    Log.e(TAG, "Get call note id fails " + e.toString());
+                }
+            }
+            cursor.close();
+        }
+        return 0;
+    }
+
+    public static String getSnippetById(ContentResolver resolver, long noteId) {
+        Cursor cursor = resolver.query(Notes.CONTENT_NOTE_URI,
+                new String [] { NoteColumns.SNIPPET },
+                NoteColumns.ID + "=?",
+                new String [] { String.valueOf(noteId)},
+                null);
+
+        if (cursor != null) {
+            String snippet = "";
+            if (cursor.moveToFirst()) {
+                snippet = cursor.getString(0);
+            }
+            cursor.close();
+            return snippet;
+        }
+        throw new IllegalArgumentException("Note is not found with id: " + noteId);
+    }
+
+    public static String getFormattedSnippet(String snippet) {
+        if (snippet != null) {
+            snippet = snippet.trim();
+            int index = snippet.indexOf('\n');
+            if (index != -1) {
+                snippet = snippet.substring(0, index);
+            }
+        }
+        return snippet;
+    }
+}
diff --git a/src/FoldersListAdapter.java b/src/FoldersListAdapter.java
new file mode 100644
index 0000000..bf5626a
--- /dev/null
+++ b/src/FoldersListAdapter.java
@@ -0,0 +1,84 @@
+/*
+ * 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.ui;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.CursorAdapter;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+
+// 该类继承自 CursorAdapter，用于适配文件夹列表的数据显示
+// 将数据库中的文件夹数据展示到列表视图中
+public class FoldersListAdapter extends CursorAdapter {
+    public static final String [] PROJECTION = {
+        NoteColumns.ID,
+        NoteColumns.SNIPPET
+    };
+
+    public static final int ID_COLUMN   = 0;
+    public static final int NAME_COLUMN = 1;
+    // 构造函数，初始化布局加载器
+    public FoldersListAdapter(Context context, Cursor c) {
+        super(context, c);
+        // TODO Auto-generated constructor stub
+    }
+
+    @Override
+    public View newView(Context context, Cursor cursor, ViewGroup parent) {
+        // 加载文件夹列表项的布局
+        return new FolderListItem(context);
+    }
+
+    @Override
+    public void bindView(View view, Context context, Cursor cursor) {
+        // 获取文件夹名称的 TextView
+        if (view instanceof FolderListItem) {
+            String folderName = (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
+                    .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+            ((FolderListItem) view).bind(folderName);
+        }
+    }
+
+    public String getFolderName(Context context, int position) {
+        Cursor cursor = (Cursor) getItem(position);
+        return (cursor.getLong(ID_COLUMN) == Notes.ID_ROOT_FOLDER) ? context
+                .getString(R.string.menu_move_parent_folder) : cursor.getString(NAME_COLUMN);
+    }
+
+    private class FolderListItem extends LinearLayout {
+        private TextView mName;
+
+        public FolderListItem(Context context) {
+            super(context);
+            inflate(context, R.layout.folder_list_item, this);
+            // 获取当前文件夹的名称
+            mName = (TextView) findViewById(R.id.tv_folder_name);
+        }
+
+        public void bind(String name) {
+            mName.setText(name);
+        }
+    }
+
+}
diff --git a/src/NoteEditActivity.java b/src/NoteEditActivity.java
index 3f167f0..cd61ada 100644
--- a/src/NoteEditActivity.java
+++ b/src/NoteEditActivity.java
@@ -190,6 +190,7 @@ public class NoteEditActivity extends Activity implements OnClickListener,
          */
         mWorkingNote = null;
         if (TextUtils.equals(Intent.ACTION_VIEW, intent.getAction())) {
+            // 获取传入的便签 ID
             long noteId = intent.getLongExtra(Intent.EXTRA_UID, 0);
             mUserQuery = "";
 
@@ -814,7 +815,7 @@ public class NoteEditActivity extends Activity implements OnClickListener,
         }
         return hasChecked;
     }
-
+    // 保存便签
     private boolean saveNote() {
         getWorkingText();
         boolean saved = mWorkingNote.saveNote();
diff --git a/src/Notes.java b/src/Notes.java
new file mode 100644
index 0000000..994c526
--- /dev/null
+++ b/src/Notes.java
@@ -0,0 +1,280 @@
+/*
+ * 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;
+// 该类主要用于定义便签相关的常量，如数据库表结构、便签类型、URI 等信息
+// 为整个便签应用提供统一的数据常量定义，方便其他类引用和使用
+public class Notes {
+    public static final String AUTHORITY = "micode_notes";
+    public static final String TAG = "Notes";
+    public static final int TYPE_NOTE     = 0;
+    public static final int TYPE_FOLDER   = 1;
+    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;
+    public static final int ID_TEMPARAY_FOLDER = -1;
+    public static final int ID_CALL_RECORD_FOLDER = -2;
+    public static final int ID_TRASH_FOLER = -3;
+
+    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";
+
+    public static final int TYPE_WIDGET_INVALIDE      = -1;
+    public static final int TYPE_WIDGET_2X            = 0;
+    public static final int TYPE_WIDGET_4X            = 1;
+
+    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");
+
+    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";
+    }
+
+    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";
+    }
+
+    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;
+
+        public static final int MODE_CHECK_LIST = 1;
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/text_note";
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note";
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note");
+    }
+
+    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>
+         */
+        public static final String PHONE_NUMBER = DATA3;
+
+        public static final String CONTENT_TYPE = "vnd.android.cursor.dir/call_note";
+
+        public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note";
+
+        public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note");
+    }
+}
diff --git a/src/NotesListActivity.java b/src/NotesListActivity.java
new file mode 100644
index 0000000..e135067
--- /dev/null
+++ b/src/NotesListActivity.java
@@ -0,0 +1,956 @@
+/*
+ * 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.ui;
+
+import android.app.Activity;
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.appwidget.AppWidgetManager;
+import android.content.AsyncQueryHandler;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.database.Cursor;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.preference.PreferenceManager;
+import android.text.Editable;
+import android.text.TextUtils;
+import android.text.TextWatcher;
+import android.util.Log;
+import android.view.ActionMode;
+import android.view.ContextMenu;
+import android.view.ContextMenu.ContextMenuInfo;
+import android.view.Display;
+import android.view.HapticFeedbackConstants;
+import android.view.LayoutInflater;
+import android.view.Menu;
+import android.view.MenuItem;
+import android.view.MenuItem.OnMenuItemClickListener;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnCreateContextMenuListener;
+import android.view.View.OnTouchListener;
+import android.view.inputmethod.InputMethodManager;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemClickListener;
+import android.widget.AdapterView.OnItemLongClickListener;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.ListView;
+import android.widget.PopupMenu;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import net.micode.notes.R;
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.gtask.remote.GTaskSyncService;
+import net.micode.notes.model.WorkingNote;
+import net.micode.notes.tool.BackupUtils;
+import net.micode.notes.tool.DataUtils;
+import net.micode.notes.tool.ResourceParser;
+import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
+import net.micode.notes.widget.NoteWidgetProvider_2x;
+import net.micode.notes.widget.NoteWidgetProvider_4x;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.HashSet;
+// 该类用于显示便签列表，并处理用户与便签列表的交互
+// 如点击便签进入编辑界面、选择便签进行移动等操作
+public class NotesListActivity extends Activity implements OnClickListener, OnItemLongClickListener {
+    private static final int FOLDER_NOTE_LIST_QUERY_TOKEN = 0;
+
+    private static final int FOLDER_LIST_QUERY_TOKEN      = 1;
+
+    private static final int MENU_FOLDER_DELETE = 0;
+
+    private static final int MENU_FOLDER_VIEW = 1;
+
+    private static final int MENU_FOLDER_CHANGE_NAME = 2;
+
+    private static final String PREFERENCE_ADD_INTRODUCTION = "net.micode.notes.introduction";
+
+    private enum ListEditState {
+        NOTE_LIST, SUB_FOLDER, CALL_RECORD_FOLDER
+    };
+
+    private ListEditState mState;
+
+    private BackgroundQueryHandler mBackgroundQueryHandler;
+
+    private NotesListAdapter mNotesListAdapter;
+
+    private ListView mNotesListView;
+
+    private Button mAddNewNote;
+
+    private boolean mDispatch;
+
+    private int mOriginY;
+
+    private int mDispatchY;
+
+    private TextView mTitleBar;
+
+    private long mCurrentFolderId;
+
+    private ContentResolver mContentResolver;
+
+    private ModeCallback mModeCallBack;
+
+    private static final String TAG = "NotesListActivity";
+
+    public static final int NOTES_LISTVIEW_SCROLL_RATE = 30;
+
+    private NoteItemData mFocusNoteDataItem;
+
+    private static final String NORMAL_SELECTION = NoteColumns.PARENT_ID + "=?";
+
+    private static final String ROOT_FOLDER_SELECTION = "(" + NoteColumns.TYPE + "<>"
+            + Notes.TYPE_SYSTEM + " AND " + NoteColumns.PARENT_ID + "=?)" + " OR ("
+            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER + " AND "
+            + NoteColumns.NOTES_COUNT + ">0)";
+
+    private final static int REQUEST_CODE_OPEN_NODE = 102;
+    private final static int REQUEST_CODE_NEW_NODE  = 103;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.note_list);
+        initResources();
+
+        /**
+         * Insert an introduction when user firstly use this application
+         */
+        setAppInfoFromRawRes();
+    }
+
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (resultCode == RESULT_OK
+                && (requestCode == REQUEST_CODE_OPEN_NODE || requestCode == REQUEST_CODE_NEW_NODE)) {
+            // 编辑或新建便签成功，刷新便签列表
+            mNotesListAdapter.changeCursor(null);
+        } else {
+            super.onActivityResult(requestCode, resultCode, data);
+        }
+    }
+
+    private void setAppInfoFromRawRes() {
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
+        if (!sp.getBoolean(PREFERENCE_ADD_INTRODUCTION, false)) {
+            StringBuilder sb = new StringBuilder();
+            InputStream in = null;
+            try {
+                 in = getResources().openRawResource(R.raw.introduction);
+                if (in != null) {
+                    InputStreamReader isr = new InputStreamReader(in);
+                    BufferedReader br = new BufferedReader(isr);
+                    char [] buf = new char[1024];
+                    int len = 0;
+                    while ((len = br.read(buf)) > 0) {
+                        sb.append(buf, 0, len);
+                    }
+                } else {
+                    Log.e(TAG, "Read introduction file error");
+                    return;
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+                return;
+            } finally {
+                if(in != null) {
+                    try {
+                        in.close();
+                    } catch (IOException e) {
+                        // TODO Auto-generated catch block
+                        e.printStackTrace();
+                    }
+                }
+            }
+
+            WorkingNote note = WorkingNote.createEmptyNote(this, Notes.ID_ROOT_FOLDER,
+                    AppWidgetManager.INVALID_APPWIDGET_ID, Notes.TYPE_WIDGET_INVALIDE,
+                    ResourceParser.RED);
+            note.setWorkingText(sb.toString());
+            if (note.saveNote()) {
+                sp.edit().putBoolean(PREFERENCE_ADD_INTRODUCTION, true).commit();
+            } else {
+                Log.e(TAG, "Save introduction note error");
+                return;
+            }
+        }
+    }
+
+    @Override
+    protected void onStart() {
+        super.onStart();
+        startAsyncNotesListQuery();
+    }
+
+    private void initResources() {
+        mContentResolver = this.getContentResolver();
+        mBackgroundQueryHandler = new BackgroundQueryHandler(this.getContentResolver());
+        mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+        mNotesListView = (ListView) findViewById(R.id.notes_list);
+        mNotesListView.addFooterView(LayoutInflater.from(this).inflate(R.layout.note_list_footer, null),
+                null, false);
+        mNotesListView.setOnItemClickListener(new OnListItemClickListener());
+        mNotesListView.setOnItemLongClickListener(this);
+        mNotesListAdapter = new NotesListAdapter(this);
+        mNotesListView.setAdapter(mNotesListAdapter);
+        mAddNewNote = (Button) findViewById(R.id.btn_new_note);
+        mAddNewNote.setOnClickListener(this);
+        mAddNewNote.setOnTouchListener(new NewNoteOnTouchListener());
+        mDispatch = false;
+        mDispatchY = 0;
+        mOriginY = 0;
+        mTitleBar = (TextView) findViewById(R.id.tv_title_bar);
+        mState = ListEditState.NOTE_LIST;
+        mModeCallBack = new ModeCallback();
+    }
+
+    private class ModeCallback implements ListView.MultiChoiceModeListener, OnMenuItemClickListener {
+        private DropdownMenu mDropDownMenu;
+        private ActionMode mActionMode;
+        private MenuItem mMoveMenu;
+
+        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
+            getMenuInflater().inflate(R.menu.note_list_options, menu);
+            menu.findItem(R.id.delete).setOnMenuItemClickListener(this);
+            mMoveMenu = menu.findItem(R.id.move);
+            if (mFocusNoteDataItem.getParentId() == Notes.ID_CALL_RECORD_FOLDER
+                    || DataUtils.getUserFolderCount(mContentResolver) == 0) {
+                mMoveMenu.setVisible(false);
+            } else {
+                mMoveMenu.setVisible(true);
+                mMoveMenu.setOnMenuItemClickListener(this);
+            }
+            mActionMode = mode;
+            mNotesListAdapter.setChoiceMode(true);
+            mNotesListView.setLongClickable(false);
+            mAddNewNote.setVisibility(View.GONE);
+
+            View customView = LayoutInflater.from(NotesListActivity.this).inflate(
+                    R.layout.note_list_dropdown_menu, null);
+            mode.setCustomView(customView);
+            mDropDownMenu = new DropdownMenu(NotesListActivity.this,
+                    (Button) customView.findViewById(R.id.selection_menu),
+                    R.menu.note_list_dropdown);
+            mDropDownMenu.setOnDropdownMenuItemClickListener(new PopupMenu.OnMenuItemClickListener(){
+                public boolean onMenuItemClick(MenuItem item) {
+                    mNotesListAdapter.selectAll(!mNotesListAdapter.isAllSelected());
+                    updateMenu();
+                    return true;
+                }
+
+            });
+            return true;
+        }
+
+        private void updateMenu() {
+            int selectedCount = mNotesListAdapter.getSelectedCount();
+            // Update dropdown menu
+            String format = getResources().getString(R.string.menu_select_title, selectedCount);
+            mDropDownMenu.setTitle(format);
+            MenuItem item = mDropDownMenu.findItem(R.id.action_select_all);
+            if (item != null) {
+                if (mNotesListAdapter.isAllSelected()) {
+                    item.setChecked(true);
+                    item.setTitle(R.string.menu_deselect_all);
+                } else {
+                    item.setChecked(false);
+                    item.setTitle(R.string.menu_select_all);
+                }
+            }
+        }
+
+        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
+            // TODO Auto-generated method stub
+            return false;
+        }
+
+        public void onDestroyActionMode(ActionMode mode) {
+            mNotesListAdapter.setChoiceMode(false);
+            mNotesListView.setLongClickable(true);
+            mAddNewNote.setVisibility(View.VISIBLE);
+        }
+
+        public void finishActionMode() {
+            mActionMode.finish();
+        }
+
+        public void onItemCheckedStateChanged(ActionMode mode, int position, long id,
+                boolean checked) {
+            mNotesListAdapter.setCheckedItem(position, checked);
+            updateMenu();
+        }
+
+        public boolean onMenuItemClick(MenuItem item) {
+            if (mNotesListAdapter.getSelectedCount() == 0) {
+                Toast.makeText(NotesListActivity.this, getString(R.string.menu_select_none),
+                        Toast.LENGTH_SHORT).show();
+                return true;
+            }
+
+            switch (item.getItemId()) {
+                case R.id.delete:
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(getString(R.string.alert_title_delete));
+                    builder.setIcon(android.R.drawable.ic_dialog_alert);
+                    builder.setMessage(getString(R.string.alert_message_delete_notes,
+                                             mNotesListAdapter.getSelectedCount()));
+                    builder.setPositiveButton(android.R.string.ok,
+                                             new DialogInterface.OnClickListener() {
+                                                 public void onClick(DialogInterface dialog,
+                                                         int which) {
+                                                     batchDelete();
+                                                 }
+                                             });
+                    builder.setNegativeButton(android.R.string.cancel, null);
+                    builder.show();
+                    break;
+                case R.id.move:
+                    startQueryDestinationFolders();
+                    break;
+                default:
+                    return false;
+            }
+            return true;
+        }
+    }
+
+    private class NewNoteOnTouchListener implements OnTouchListener {
+
+        public boolean onTouch(View v, MotionEvent event) {
+            switch (event.getAction()) {
+                case MotionEvent.ACTION_DOWN: {
+                    Display display = getWindowManager().getDefaultDisplay();
+                    int screenHeight = display.getHeight();
+                    int newNoteViewHeight = mAddNewNote.getHeight();
+                    int start = screenHeight - newNoteViewHeight;
+                    int eventY = start + (int) event.getY();
+                    /**
+                     * Minus TitleBar's height
+                     */
+                    if (mState == ListEditState.SUB_FOLDER) {
+                        eventY -= mTitleBar.getHeight();
+                        start -= mTitleBar.getHeight();
+                    }
+                    /**
+                     * HACKME:When click the transparent part of "New Note" button, dispatch
+                     * the event to the list view behind this button. The transparent part of
+                     * "New Note" button could be expressed by formula y=-0.12x+94（Unit:pixel）
+                     * and the line top of the button. The coordinate based on left of the "New
+                     * Note" button. The 94 represents maximum height of the transparent part.
+                     * Notice that, if the background of the button changes, the formula should
+                     * also change. This is very bad, just for the UI designer's strong requirement.
+                     */
+                    if (event.getY() < (event.getX() * (-0.12) + 94)) {
+                        View view = mNotesListView.getChildAt(mNotesListView.getChildCount() - 1
+                                - mNotesListView.getFooterViewsCount());
+                        if (view != null && view.getBottom() > start
+                                && (view.getTop() < (start + 94))) {
+                            mOriginY = (int) event.getY();
+                            mDispatchY = eventY;
+                            event.setLocation(event.getX(), mDispatchY);
+                            mDispatch = true;
+                            return mNotesListView.dispatchTouchEvent(event);
+                        }
+                    }
+                    break;
+                }
+                case MotionEvent.ACTION_MOVE: {
+                    if (mDispatch) {
+                        mDispatchY += (int) event.getY() - mOriginY;
+                        event.setLocation(event.getX(), mDispatchY);
+                        return mNotesListView.dispatchTouchEvent(event);
+                    }
+                    break;
+                }
+                default: {
+                    if (mDispatch) {
+                        event.setLocation(event.getX(), mDispatchY);
+                        mDispatch = false;
+                        return mNotesListView.dispatchTouchEvent(event);
+                    }
+                    break;
+                }
+            }
+            return false;
+        }
+
+    };
+
+    private void startAsyncNotesListQuery() {
+        String selection = (mCurrentFolderId == Notes.ID_ROOT_FOLDER) ? ROOT_FOLDER_SELECTION
+                : NORMAL_SELECTION;
+        mBackgroundQueryHandler.startQuery(FOLDER_NOTE_LIST_QUERY_TOKEN, null,
+                Notes.CONTENT_NOTE_URI, NoteItemData.PROJECTION, selection, new String[] {
+                    String.valueOf(mCurrentFolderId)
+                }, NoteColumns.TYPE + " DESC," + NoteColumns.MODIFIED_DATE + " DESC");
+    }
+
+    private final class BackgroundQueryHandler extends AsyncQueryHandler {
+        public BackgroundQueryHandler(ContentResolver contentResolver) {
+            super(contentResolver);
+        }
+
+        @Override
+        protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
+            switch (token) {
+                case FOLDER_NOTE_LIST_QUERY_TOKEN:
+                    mNotesListAdapter.changeCursor(cursor);
+                    break;
+                case FOLDER_LIST_QUERY_TOKEN:
+                    if (cursor != null && cursor.getCount() > 0) {
+                        showFolderListMenu(cursor);
+                    } else {
+                        Log.e(TAG, "Query folder failed");
+                    }
+                    break;
+                default:
+                    return;
+            }
+        }
+    }
+
+    private void showFolderListMenu(Cursor cursor) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+        builder.setTitle(R.string.menu_title_select_folder);
+        final FoldersListAdapter adapter = new FoldersListAdapter(this, cursor);
+        builder.setAdapter(adapter, new DialogInterface.OnClickListener() {
+
+            public void onClick(DialogInterface dialog, int which) {
+                DataUtils.batchMoveToFolder(mContentResolver,
+                        mNotesListAdapter.getSelectedItemIds(), adapter.getItemId(which));
+                Toast.makeText(
+                        NotesListActivity.this,
+                        getString(R.string.format_move_notes_to_folder,
+                                mNotesListAdapter.getSelectedCount(),
+                                adapter.getFolderName(NotesListActivity.this, which)),
+                        Toast.LENGTH_SHORT).show();
+                mModeCallBack.finishActionMode();
+            }
+        });
+        builder.show();
+    }
+
+    private void createNewNote() {
+        Intent intent = new Intent(this, NoteEditActivity.class);
+        intent.setAction(Intent.ACTION_INSERT_OR_EDIT);
+        intent.putExtra(Notes.INTENT_EXTRA_FOLDER_ID, mCurrentFolderId);
+        this.startActivityForResult(intent, REQUEST_CODE_NEW_NODE);
+    }
+
+    private void batchDelete() {
+        new AsyncTask<Void, Void, HashSet<AppWidgetAttribute>>() {
+            protected HashSet<AppWidgetAttribute> doInBackground(Void... unused) {
+                HashSet<AppWidgetAttribute> widgets = mNotesListAdapter.getSelectedWidget();
+                if (!isSyncMode()) {
+                    // if not synced, delete notes directly
+                    if (DataUtils.batchDeleteNotes(mContentResolver, mNotesListAdapter
+                            .getSelectedItemIds())) {
+                    } else {
+                        Log.e(TAG, "Delete notes error, should not happens");
+                    }
+                } else {
+                    // in sync mode, we'll move the deleted note into the trash
+                    // folder
+                    if (!DataUtils.batchMoveToFolder(mContentResolver, mNotesListAdapter
+                            .getSelectedItemIds(), Notes.ID_TRASH_FOLER)) {
+                        Log.e(TAG, "Move notes to trash folder error, should not happens");
+                    }
+                }
+                return widgets;
+            }
+
+            @Override
+            protected void onPostExecute(HashSet<AppWidgetAttribute> widgets) {
+                if (widgets != null) {
+                    for (AppWidgetAttribute widget : widgets) {
+                        if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                                && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
+                            updateWidget(widget.widgetId, widget.widgetType);
+                        }
+                    }
+                }
+                mModeCallBack.finishActionMode();
+            }
+        }.execute();
+    }
+
+    private void deleteFolder(long folderId) {
+        if (folderId == Notes.ID_ROOT_FOLDER) {
+            Log.e(TAG, "Wrong folder id, should not happen " + folderId);
+            return;
+        }
+
+        HashSet<Long> ids = new HashSet<Long>();
+        ids.add(folderId);
+        HashSet<AppWidgetAttribute> widgets = DataUtils.getFolderNoteWidget(mContentResolver,
+                folderId);
+        if (!isSyncMode()) {
+            // if not synced, delete folder directly
+            DataUtils.batchDeleteNotes(mContentResolver, ids);
+        } else {
+            // in sync mode, we'll move the deleted folder into the trash folder
+            DataUtils.batchMoveToFolder(mContentResolver, ids, Notes.ID_TRASH_FOLER);
+        }
+        if (widgets != null) {
+            for (AppWidgetAttribute widget : widgets) {
+                if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                        && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
+                    updateWidget(widget.widgetId, widget.widgetType);
+                }
+            }
+        }
+    }
+
+    private void openNode(NoteItemData data) {
+        Intent intent = new Intent(this, NoteEditActivity.class);
+        intent.setAction(Intent.ACTION_VIEW);
+        intent.putExtra(Intent.EXTRA_UID, data.getId());
+        this.startActivityForResult(intent, REQUEST_CODE_OPEN_NODE);
+    }
+
+    private void openFolder(NoteItemData data) {
+        mCurrentFolderId = data.getId();
+        startAsyncNotesListQuery();
+        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
+            mState = ListEditState.CALL_RECORD_FOLDER;
+            mAddNewNote.setVisibility(View.GONE);
+        } else {
+            mState = ListEditState.SUB_FOLDER;
+        }
+        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
+            mTitleBar.setText(R.string.call_record_folder_name);
+        } else {
+            mTitleBar.setText(data.getSnippet());
+        }
+        mTitleBar.setVisibility(View.VISIBLE);
+    }
+
+    public void onClick(View v) {
+        switch (v.getId()) {
+            case R.id.btn_new_note:
+                createNewNote();
+                break;
+            default:
+                break;
+        }
+    }
+
+    private void showSoftInput() {
+        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
+        if (inputMethodManager != null) {
+            inputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
+        }
+    }
+
+    private void hideSoftInput(View view) {
+        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
+        inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
+    }
+
+    private void showCreateOrModifyFolderDialog(final boolean create) {
+        final AlertDialog.Builder builder = new AlertDialog.Builder(this);
+        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_text, null);
+        final EditText etName = (EditText) view.findViewById(R.id.et_foler_name);
+        showSoftInput();
+        if (!create) {
+            if (mFocusNoteDataItem != null) {
+                etName.setText(mFocusNoteDataItem.getSnippet());
+                builder.setTitle(getString(R.string.menu_folder_change_name));
+            } else {
+                Log.e(TAG, "The long click data item is null");
+                return;
+            }
+        } else {
+            etName.setText("");
+            builder.setTitle(this.getString(R.string.menu_create_folder));
+        }
+
+        builder.setPositiveButton(android.R.string.ok, null);
+        builder.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
+            public void onClick(DialogInterface dialog, int which) {
+                hideSoftInput(etName);
+            }
+        });
+
+        final Dialog dialog = builder.setView(view).show();
+        final Button positive = (Button)dialog.findViewById(android.R.id.button1);
+        positive.setOnClickListener(new OnClickListener() {
+            public void onClick(View v) {
+                hideSoftInput(etName);
+                String name = etName.getText().toString();
+                if (DataUtils.checkVisibleFolderName(mContentResolver, name)) {
+                    Toast.makeText(NotesListActivity.this, getString(R.string.folder_exist, name),
+                            Toast.LENGTH_LONG).show();
+                    etName.setSelection(0, etName.length());
+                    return;
+                }
+                if (!create) {
+                    if (!TextUtils.isEmpty(name)) {
+                        ContentValues values = new ContentValues();
+                        values.put(NoteColumns.SNIPPET, name);
+                        values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+                        values.put(NoteColumns.LOCAL_MODIFIED, 1);
+                        mContentResolver.update(Notes.CONTENT_NOTE_URI, values, NoteColumns.ID
+                                + "=?", new String[] {
+                            String.valueOf(mFocusNoteDataItem.getId())
+                        });
+                    }
+                } else if (!TextUtils.isEmpty(name)) {
+                    ContentValues values = new ContentValues();
+                    values.put(NoteColumns.SNIPPET, name);
+                    values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
+                    mContentResolver.insert(Notes.CONTENT_NOTE_URI, values);
+                }
+                dialog.dismiss();
+            }
+        });
+
+        if (TextUtils.isEmpty(etName.getText())) {
+            positive.setEnabled(false);
+        }
+        /**
+         * When the name edit text is null, disable the positive button
+         */
+        etName.addTextChangedListener(new TextWatcher() {
+            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+                // TODO Auto-generated method stub
+
+            }
+
+            public void onTextChanged(CharSequence s, int start, int before, int count) {
+                if (TextUtils.isEmpty(etName.getText())) {
+                    positive.setEnabled(false);
+                } else {
+                    positive.setEnabled(true);
+                }
+            }
+
+            public void afterTextChanged(Editable s) {
+                // TODO Auto-generated method stub
+
+            }
+        });
+    }
+
+    @Override
+    public void onBackPressed() {
+        switch (mState) {
+            case SUB_FOLDER:
+                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+                mState = ListEditState.NOTE_LIST;
+                startAsyncNotesListQuery();
+                mTitleBar.setVisibility(View.GONE);
+                break;
+            case CALL_RECORD_FOLDER:
+                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
+                mState = ListEditState.NOTE_LIST;
+                mAddNewNote.setVisibility(View.VISIBLE);
+                mTitleBar.setVisibility(View.GONE);
+                startAsyncNotesListQuery();
+                break;
+            case NOTE_LIST:
+                super.onBackPressed();
+                break;
+            default:
+                break;
+        }
+    }
+
+    private void updateWidget(int appWidgetId, int appWidgetType) {
+        Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
+        if (appWidgetType == Notes.TYPE_WIDGET_2X) {
+            intent.setClass(this, NoteWidgetProvider_2x.class);
+        } else if (appWidgetType == Notes.TYPE_WIDGET_4X) {
+            intent.setClass(this, NoteWidgetProvider_4x.class);
+        } else {
+            Log.e(TAG, "Unspported widget type");
+            return;
+        }
+
+        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, new int[] {
+            appWidgetId
+        });
+
+        sendBroadcast(intent);
+        setResult(RESULT_OK, intent);
+    }
+
+    private final OnCreateContextMenuListener mFolderOnCreateContextMenuListener = new OnCreateContextMenuListener() {
+        public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
+            if (mFocusNoteDataItem != null) {
+                menu.setHeaderTitle(mFocusNoteDataItem.getSnippet());
+                menu.add(0, MENU_FOLDER_VIEW, 0, R.string.menu_folder_view);
+                menu.add(0, MENU_FOLDER_DELETE, 0, R.string.menu_folder_delete);
+                menu.add(0, MENU_FOLDER_CHANGE_NAME, 0, R.string.menu_folder_change_name);
+            }
+        }
+    };
+
+    @Override
+    public void onContextMenuClosed(Menu menu) {
+        if (mNotesListView != null) {
+            mNotesListView.setOnCreateContextMenuListener(null);
+        }
+        super.onContextMenuClosed(menu);
+    }
+
+    @Override
+    public boolean onContextItemSelected(MenuItem item) {
+        if (mFocusNoteDataItem == null) {
+            Log.e(TAG, "The long click data item is null");
+            return false;
+        }
+        switch (item.getItemId()) {
+            case MENU_FOLDER_VIEW:
+                openFolder(mFocusNoteDataItem);
+                break;
+            case MENU_FOLDER_DELETE:
+                AlertDialog.Builder builder = new AlertDialog.Builder(this);
+                builder.setTitle(getString(R.string.alert_title_delete));
+                builder.setIcon(android.R.drawable.ic_dialog_alert);
+                builder.setMessage(getString(R.string.alert_message_delete_folder));
+                builder.setPositiveButton(android.R.string.ok,
+                        new DialogInterface.OnClickListener() {
+                            public void onClick(DialogInterface dialog, int which) {
+                                deleteFolder(mFocusNoteDataItem.getId());
+                            }
+                        });
+                builder.setNegativeButton(android.R.string.cancel, null);
+                builder.show();
+                break;
+            case MENU_FOLDER_CHANGE_NAME:
+                showCreateOrModifyFolderDialog(false);
+                break;
+            default:
+                break;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean onPrepareOptionsMenu(Menu menu) {
+        menu.clear();
+        if (mState == ListEditState.NOTE_LIST) {
+            getMenuInflater().inflate(R.menu.note_list, menu);
+            // set sync or sync_cancel
+            menu.findItem(R.id.menu_sync).setTitle(
+                    GTaskSyncService.isSyncing() ? R.string.menu_sync_cancel : R.string.menu_sync);
+        } else if (mState == ListEditState.SUB_FOLDER) {
+            getMenuInflater().inflate(R.menu.sub_folder, menu);
+        } else if (mState == ListEditState.CALL_RECORD_FOLDER) {
+            getMenuInflater().inflate(R.menu.call_record_folder, menu);
+        } else {
+            Log.e(TAG, "Wrong state:" + mState);
+        }
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case R.id.menu_new_folder: {
+                showCreateOrModifyFolderDialog(true);
+                break;
+            }
+            case R.id.menu_export_text: {
+                exportNoteToText();
+                break;
+            }
+            case R.id.menu_sync: {
+                if (isSyncMode()) {
+                    if (TextUtils.equals(item.getTitle(), getString(R.string.menu_sync))) {
+                        GTaskSyncService.startSync(this);
+                    } else {
+                        GTaskSyncService.cancelSync(this);
+                    }
+                } else {
+                    startPreferenceActivity();
+                }
+                break;
+            }
+            case R.id.menu_setting: {
+                startPreferenceActivity();
+                break;
+            }
+            case R.id.menu_new_note: {
+                createNewNote();
+                break;
+            }
+            case R.id.menu_search:
+                onSearchRequested();
+                break;
+            default:
+                break;
+        }
+        return true;
+    }
+
+    @Override
+    public boolean onSearchRequested() {
+        startSearch(null, false, null /* appData */, false);
+        return true;
+    }
+
+    private void exportNoteToText() {
+        final BackupUtils backup = BackupUtils.getInstance(NotesListActivity.this);
+        new AsyncTask<Void, Void, Integer>() {
+
+            @Override
+            protected Integer doInBackground(Void... unused) {
+                return backup.exportToText();
+            }
+
+            @Override
+            protected void onPostExecute(Integer result) {
+                if (result == BackupUtils.STATE_SD_CARD_UNMOUONTED) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.failed_sdcard_export));
+                    builder.setMessage(NotesListActivity.this
+                            .getString(R.string.error_sdcard_unmounted));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                } else if (result == BackupUtils.STATE_SUCCESS) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.success_sdcard_export));
+                    builder.setMessage(NotesListActivity.this.getString(
+                            R.string.format_exported_file_location, backup
+                                    .getExportedTextFileName(), backup.getExportedTextFileDir()));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                } else if (result == BackupUtils.STATE_SYSTEM_ERROR) {
+                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
+                    builder.setTitle(NotesListActivity.this
+                            .getString(R.string.failed_sdcard_export));
+                    builder.setMessage(NotesListActivity.this
+                            .getString(R.string.error_sdcard_export));
+                    builder.setPositiveButton(android.R.string.ok, null);
+                    builder.show();
+                }
+            }
+
+        }.execute();
+    }
+
+    private boolean isSyncMode() {
+        return NotesPreferenceActivity.getSyncAccountName(this).trim().length() > 0;
+    }
+
+    private void startPreferenceActivity() {
+        Activity from = getParent() != null ? getParent() : this;
+        Intent intent = new Intent(from, NotesPreferenceActivity.class);
+        from.startActivityIfNeeded(intent, -1);
+    }
+
+    private class OnListItemClickListener implements OnItemClickListener {
+
+        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+            if (view instanceof NotesListItem) {
+                NoteItemData item = ((NotesListItem) view).getItemData();
+                if (mNotesListAdapter.isInChoiceMode()) {
+                    if (item.getType() == Notes.TYPE_NOTE) {
+                        position = position - mNotesListView.getHeaderViewsCount();
+                        mModeCallBack.onItemCheckedStateChanged(null, position, id,
+                                !mNotesListAdapter.isSelectedItem(position));
+                    }
+                    return;
+                }
+
+                switch (mState) {
+                    case NOTE_LIST:
+                        if (item.getType() == Notes.TYPE_FOLDER
+                                || item.getType() == Notes.TYPE_SYSTEM) {
+                            openFolder(item);
+                        } else if (item.getType() == Notes.TYPE_NOTE) {
+                            openNode(item);
+                        } else {
+                            Log.e(TAG, "Wrong note type in NOTE_LIST");
+                        }
+                        break;
+                    case SUB_FOLDER:
+                    case CALL_RECORD_FOLDER:
+                        if (item.getType() == Notes.TYPE_NOTE) {
+                            openNode(item);
+                        } else {
+                            Log.e(TAG, "Wrong note type in SUB_FOLDER");
+                        }
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
+
+    }
+
+    private void startQueryDestinationFolders() {
+        String selection = NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>? AND " + NoteColumns.ID + "<>?";
+        selection = (mState == ListEditState.NOTE_LIST) ? selection:
+            "(" + selection + ") OR (" + NoteColumns.ID + "=" + Notes.ID_ROOT_FOLDER + ")";
+
+        mBackgroundQueryHandler.startQuery(FOLDER_LIST_QUERY_TOKEN,
+                null,
+                Notes.CONTENT_NOTE_URI,
+                FoldersListAdapter.PROJECTION,
+                selection,
+                new String[] {
+                        String.valueOf(Notes.TYPE_FOLDER),
+                        String.valueOf(Notes.ID_TRASH_FOLER),
+                        String.valueOf(mCurrentFolderId)
+                },
+                NoteColumns.MODIFIED_DATE + " DESC");
+    }
+
+    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
+        if (view instanceof NotesListItem) {
+            mFocusNoteDataItem = ((NotesListItem) view).getItemData();
+            if (mFocusNoteDataItem.getType() == Notes.TYPE_NOTE && !mNotesListAdapter.isInChoiceMode()) {
+                if (mNotesListView.startActionMode(mModeCallBack) != null) {
+                    mModeCallBack.onItemCheckedStateChanged(null, position, id, true);
+                    mNotesListView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
+                } else {
+                    Log.e(TAG, "startActionMode fails");
+                }
+            } else if (mFocusNoteDataItem.getType() == Notes.TYPE_FOLDER) {
+                mNotesListView.setOnCreateContextMenuListener(mFolderOnCreateContextMenuListener);
+            }
+        }
+        return false;
+    }
+}
diff --git a/src/NotesProvider.java b/src/NotesProvider.java
new file mode 100644
index 0000000..af91299
--- /dev/null
+++ b/src/NotesProvider.java
@@ -0,0 +1,319 @@
+/*
+ * 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;
+
+
+// 该类继承自 ContentProvider，用于管理便签数据的访问
+// 提供对便签数据的增删改查操作，通过 ContentResolver 供其他组件调用
+public class NotesProvider extends ContentProvider {
+    // 定义 UriMatcher，用于匹配不同的 URI 模式
+    private static final UriMatcher mMatcher;
+
+    private NotesDatabaseHelper mHelper;
+
+    private static final String TAG = "NotesProvider";
+
+    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;
+
+    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.
+     */
+    private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + ","
+        + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+        + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+        + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + ","
+        + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + ","
+        + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA;
+
+    private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+        + " FROM " + TABLE.NOTE
+        + " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+        + " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+        + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+
+    @Override
+    public boolean onCreate() {
+        // 初始化数据库帮助类
+        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:
+                //查询所有便签
+                c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
+                        sortOrder);
+                break;
+            case URI_NOTE_ITEM:
+                //查询单个便签
+                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);
+        }
+        // 设置通知 URI，当数据变化时通知观察者
+        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:
+                //插入便签数据
+                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) {
+            // 插入成功，返回新便签的 URI
+            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) {
+        int count = 0;
+        String id = null;
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean deleteData = false;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 更新所有匹配条件的便签
+                selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
+                count = db.delete(TABLE.NOTE, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                // 更新单个便签
+                id = uri.getPathSegments().get(1);
+                /**
+                 * ID that smaller than 0 is system folder which is not allowed to
+                 * trash
+                 */
+                long noteId = Long.valueOf(id);
+                if (noteId <= 0) {
+                    break;
+                }
+                count = db.delete(TABLE.NOTE,
+                        NoteColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                count = db.delete(TABLE.DATA, selection, selectionArgs);
+                deleteData = true;
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                count = db.delete(TABLE.DATA,
+                        DataColumns.ID + "=" + id + parseSelection(selection), selectionArgs);
+                deleteData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        //通知数据变化
+        if (count > 0) {
+            if (deleteData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+
+    @Override
+    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+        int count = 0;
+        String id = null;
+        SQLiteDatabase db = mHelper.getWritableDatabase();
+        boolean updateData = false;
+        switch (mMatcher.match(uri)) {
+            case URI_NOTE:
+                // 删除所有匹配条件的便签
+                increaseNoteVersion(-1, selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, selection, selectionArgs);
+                break;
+            case URI_NOTE_ITEM:
+                //删除单个便签
+                id = uri.getPathSegments().get(1);
+                increaseNoteVersion(Long.valueOf(id), selection, selectionArgs);
+                count = db.update(TABLE.NOTE, values, NoteColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                break;
+            case URI_DATA:
+                count = db.update(TABLE.DATA, values, selection, selectionArgs);
+                updateData = true;
+                break;
+            case URI_DATA_ITEM:
+                id = uri.getPathSegments().get(1);
+                count = db.update(TABLE.DATA, values, DataColumns.ID + "=" + id
+                        + parseSelection(selection), selectionArgs);
+                updateData = true;
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown URI " + uri);
+        }
+        // 通知数据变化
+        if (count > 0) {
+            if (updateData) {
+                getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
+            }
+            getContext().getContentResolver().notifyChange(uri, null);
+        }
+        return count;
+    }
+
+    private String parseSelection(String selection) {
+        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;
+    }
+
+}
diff --git a/src/WorkingNote.java b/src/WorkingNote.java
new file mode 100644
index 0000000..65c6ed6
--- /dev/null
+++ b/src/WorkingNote.java
@@ -0,0 +1,369 @@
+/*
+ * 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.model;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ContentUris;
+import android.content.Context;
+import android.database.Cursor;
+import android.text.TextUtils;
+import android.util.Log;
+
+import net.micode.notes.data.Notes;
+import net.micode.notes.data.Notes.CallNote;
+import net.micode.notes.data.Notes.DataColumns;
+import net.micode.notes.data.Notes.DataConstants;
+import net.micode.notes.data.Notes.NoteColumns;
+import net.micode.notes.data.Notes.TextNote;
+import net.micode.notes.tool.ResourceParser.NoteBgResources;
+
+// 该类封装了便签的业务逻辑，负责便签的创建、保存、加载等操作
+// 与 NotesProvider 交互，将便签数据持久化到数据库
+public class WorkingNote {
+    // Note for the working note
+    private Note mNote;
+    // Note Id
+    private long mNoteId;
+    // Note content
+    private String mContent;
+    // Note mode
+    private int mMode;
+
+    private long mAlertDate;
+
+    private long mModifiedDate;
+
+    private int mBgColorId;
+
+    private int mWidgetId;
+
+    private int mWidgetType;
+
+    private long mFolderId;
+
+    private Context mContext;
+
+    private static final String TAG = "WorkingNote";
+
+    private boolean mIsDeleted;
+
+    private NoteSettingChangedListener mNoteSettingStatusListener;
+
+    public static final String[] DATA_PROJECTION = new String[] {
+            DataColumns.ID,
+            DataColumns.CONTENT,
+            DataColumns.MIME_TYPE,
+            DataColumns.DATA1,
+            DataColumns.DATA2,
+            DataColumns.DATA3,
+            DataColumns.DATA4,
+    };
+
+    public static final String[] NOTE_PROJECTION = new String[] {
+            NoteColumns.PARENT_ID,
+            NoteColumns.ALERTED_DATE,
+            NoteColumns.BG_COLOR_ID,
+            NoteColumns.WIDGET_ID,
+            NoteColumns.WIDGET_TYPE,
+            NoteColumns.MODIFIED_DATE
+    };
+
+    private static final int DATA_ID_COLUMN = 0;
+
+    private static final int DATA_CONTENT_COLUMN = 1;
+
+    private static final int DATA_MIME_TYPE_COLUMN = 2;
+
+    private static final int DATA_MODE_COLUMN = 3;
+
+    private static final int NOTE_PARENT_ID_COLUMN = 0;
+
+    private static final int NOTE_ALERTED_DATE_COLUMN = 1;
+
+    private static final int NOTE_BG_COLOR_ID_COLUMN = 2;
+
+    private static final int NOTE_WIDGET_ID_COLUMN = 3;
+
+    private static final int NOTE_WIDGET_TYPE_COLUMN = 4;
+
+    private static final int NOTE_MODIFIED_DATE_COLUMN = 5;
+
+    // New note construct
+    private WorkingNote(Context context, long folderId) {
+        mContext = context;
+        mAlertDate = 0;
+        mModifiedDate = System.currentTimeMillis();
+        mFolderId = folderId;
+        mNote = new Note();
+        mNoteId = 0;
+        mIsDeleted = false;
+        mMode = 0;
+        mWidgetType = Notes.TYPE_WIDGET_INVALIDE;
+    }
+
+    // Existing note construct
+    //构造函数，用于创建一个新的便签对象
+    private WorkingNote(Context context, long noteId, long folderId) {
+        mContext = context;
+        mNoteId = noteId;
+        mFolderId = folderId;
+        mIsDeleted = false;
+        mNote = new Note();
+        loadNote();
+    }
+
+    private void loadNote() {
+        Cursor cursor = mContext.getContentResolver().query(
+                ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, mNoteId), NOTE_PROJECTION, null,
+                null, null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                mFolderId = cursor.getLong(NOTE_PARENT_ID_COLUMN);
+                mBgColorId = cursor.getInt(NOTE_BG_COLOR_ID_COLUMN);
+                mWidgetId = cursor.getInt(NOTE_WIDGET_ID_COLUMN);
+                mWidgetType = cursor.getInt(NOTE_WIDGET_TYPE_COLUMN);
+                mAlertDate = cursor.getLong(NOTE_ALERTED_DATE_COLUMN);
+                mModifiedDate = cursor.getLong(NOTE_MODIFIED_DATE_COLUMN);
+            }
+            cursor.close();
+        } else {
+            Log.e(TAG, "No note with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note with id " + mNoteId);
+        }
+        loadNoteData();
+    }
+
+    private void loadNoteData() {
+        Cursor cursor = mContext.getContentResolver().query(Notes.CONTENT_DATA_URI, DATA_PROJECTION,
+                DataColumns.NOTE_ID + "=?", new String[] {
+                    String.valueOf(mNoteId)
+                }, null);
+
+        if (cursor != null) {
+            if (cursor.moveToFirst()) {
+                do {
+                    String type = cursor.getString(DATA_MIME_TYPE_COLUMN);
+                    if (DataConstants.NOTE.equals(type)) {
+                        mContent = cursor.getString(DATA_CONTENT_COLUMN);
+                        mMode = cursor.getInt(DATA_MODE_COLUMN);
+                        mNote.setTextDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else if (DataConstants.CALL_NOTE.equals(type)) {
+                        mNote.setCallDataId(cursor.getLong(DATA_ID_COLUMN));
+                    } else {
+                        Log.d(TAG, "Wrong note type with type:" + type);
+                    }
+                } while (cursor.moveToNext());
+            }
+            cursor.close();
+        } else {
+            Log.e(TAG, "No data with id:" + mNoteId);
+            throw new IllegalArgumentException("Unable to find note's data with id " + mNoteId);
+        }
+    }
+
+    public static WorkingNote createEmptyNote(Context context, long folderId, int widgetId,
+            int widgetType, int defaultBgColorId) {
+        WorkingNote note = new WorkingNote(context, folderId);
+        note.setBgColorId(defaultBgColorId);
+        note.setWidgetId(widgetId);
+        note.setWidgetType(widgetType);
+        return note;
+    }
+    public static WorkingNote load(Context context, long id) {
+        return new WorkingNote(context, id, 0);
+    }
+    // 保存便签到数据库的方法
+    public synchronized boolean saveNote() {
+        if (isWorthSaving()) {
+            if (!existInDatabase()) {
+                if ((mNoteId = Note.getNewNoteId(mContext, mFolderId)) == 0) {
+                    Log.e(TAG, "Create new note fail with id:" + mNoteId);
+                    return false;
+                }
+            }
+
+            mNote.syncNote(mContext, mNoteId);
+
+            /**
+             * Update widget content if there exist any widget of this note
+             */
+            if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                    && mWidgetType != Notes.TYPE_WIDGET_INVALIDE
+                    && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+            }
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    public boolean existInDatabase() {
+        return mNoteId > 0;
+    }
+
+    private boolean isWorthSaving() {
+        if (mIsDeleted || (!existInDatabase() && TextUtils.isEmpty(mContent))
+                || (existInDatabase() && !mNote.isLocalModified())) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
+    public void setOnSettingStatusChangedListener(NoteSettingChangedListener l) {
+        mNoteSettingStatusListener = l;
+    }
+
+    public void setAlertDate(long date, boolean set) {
+        if (date != mAlertDate) {
+            mAlertDate = date;
+            mNote.setNoteValue(NoteColumns.ALERTED_DATE, String.valueOf(mAlertDate));
+        }
+        if (mNoteSettingStatusListener != null) {
+            mNoteSettingStatusListener.onClockAlertChanged(date, set);
+        }
+    }
+
+    public void markDeleted(boolean mark) {
+        mIsDeleted = mark;
+        if (mWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID
+                && mWidgetType != Notes.TYPE_WIDGET_INVALIDE && mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onWidgetChanged();
+        }
+    }
+
+    public void setBgColorId(int id) {
+        if (id != mBgColorId) {
+            mBgColorId = id;
+            if (mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onBackgroundColorChanged();
+            }
+            mNote.setNoteValue(NoteColumns.BG_COLOR_ID, String.valueOf(id));
+        }
+    }
+
+    public void setCheckListMode(int mode) {
+        if (mMode != mode) {
+            if (mNoteSettingStatusListener != null) {
+                mNoteSettingStatusListener.onCheckListModeChanged(mMode, mode);
+            }
+            mMode = mode;
+            mNote.setTextData(TextNote.MODE, String.valueOf(mMode));
+        }
+    }
+
+    public void setWidgetType(int type) {
+        if (type != mWidgetType) {
+            mWidgetType = type;
+            mNote.setNoteValue(NoteColumns.WIDGET_TYPE, String.valueOf(mWidgetType));
+        }
+    }
+
+    public void setWidgetId(int id) {
+        if (id != mWidgetId) {
+            mWidgetId = id;
+            mNote.setNoteValue(NoteColumns.WIDGET_ID, String.valueOf(mWidgetId));
+        }
+    }
+
+    public void setWorkingText(String text) {
+        if (!TextUtils.equals(mContent, text)) {
+            mContent = text;
+            mNote.setTextData(DataColumns.CONTENT, mContent);
+        }
+    }
+
+    public void convertToCallNote(String phoneNumber, long callDate) {
+        mNote.setCallData(CallNote.CALL_DATE, String.valueOf(callDate));
+        mNote.setCallData(CallNote.PHONE_NUMBER, phoneNumber);
+        mNote.setNoteValue(NoteColumns.PARENT_ID, String.valueOf(Notes.ID_CALL_RECORD_FOLDER));
+    }
+
+    public boolean hasClockAlert() {
+        return (mAlertDate > 0 ? true : false);
+    }
+
+    public String getContent() {
+        return mContent;
+    }
+
+    public long getAlertDate() {
+        return mAlertDate;
+    }
+
+    public long getModifiedDate() {
+        return mModifiedDate;
+    }
+
+    public int getBgColorResId() {
+        return NoteBgResources.getNoteBgResource(mBgColorId);
+    }
+
+    public int getBgColorId() {
+        return mBgColorId;
+    }
+
+    public int getTitleBgResId() {
+        return NoteBgResources.getNoteTitleBgResource(mBgColorId);
+    }
+
+    public int getCheckListMode() {
+        return mMode;
+    }
+
+    public long getNoteId() {
+        return mNoteId;
+    }
+
+    public long getFolderId() {
+        return mFolderId;
+    }
+
+    public int getWidgetId() {
+        return mWidgetId;
+    }
+
+    public int getWidgetType() {
+        return mWidgetType;
+    }
+
+    public interface NoteSettingChangedListener {
+        /**
+         * Called when the background color of current note has just changed
+         */
+        void onBackgroundColorChanged();
+
+        /**
+         * Called when user set clock
+         */
+        void onClockAlertChanged(long date, boolean set);
+
+        /**
+         * Call when user create note from widget
+         */
+        void onWidgetChanged();
+
+        /**
+         * Call when switch between check list mode and normal mode
+         * @param oldMode is previous mode before change
+         * @param newMode is new mode
+         */
+        void onCheckListModeChanged(int oldMode, int newMode);
+    }
+}
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