diff --git a/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java b/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
index 85723be..67e224d 100644
--- a/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
+++ b/app/src/main/java/net/micode/notes/ui/AlarmAlertActivity.java
@@ -39,12 +39,15 @@ import net.micode.notes.tool.DataUtils;
 
 import java.io.IOException;
 
-
+/**
+ * 闹钟提醒活动类
+ * 当便签的提醒时间到达时显示提醒对话框并播放提醒声音
+ */
 public class AlarmAlertActivity extends Activity implements OnClickListener, OnDismissListener {
-    private long mNoteId;
-    private String mSnippet;
-    private static final int SNIPPET_PREW_MAX_LEN = 60;
-    MediaPlayer mPlayer;
+    private long mNoteId;              // 提醒的便签ID
+    private String mSnippet;           // 便签摘要
+    private static final int SNIPPET_PREW_MAX_LEN = 60; // 摘要预览最大长度
+    private MediaPlayer mPlayer;       // 媒体播放器，用于播放提醒声音
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -52,8 +55,10 @@ public class AlarmAlertActivity extends Activity implements OnClickListener, OnD
         requestWindowFeature(Window.FEATURE_NO_TITLE);
 
         final Window win = getWindow();
+        // 设置窗口在锁屏状态下显示
         win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
 
+        // 如果屏幕未开启，设置窗口参数以唤醒屏幕并保持亮起
         if (!isScreenOn()) {
             win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                     | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
@@ -61,20 +66,23 @@ public class AlarmAlertActivity extends Activity implements OnClickListener, OnD
                     | WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR);
         }
 
+        // 从Intent中获取便签ID和摘要
         Intent intent = getIntent();
-
         try {
             mNoteId = Long.valueOf(intent.getData().getPathSegments().get(1));
             mSnippet = DataUtils.getSnippetById(this.getContentResolver(), mNoteId);
+            // 限制摘要长度，超过时添加省略提示
             mSnippet = mSnippet.length() > SNIPPET_PREW_MAX_LEN ? mSnippet.substring(0,
                     SNIPPET_PREW_MAX_LEN) + getResources().getString(R.string.notelist_string_info)
                     : mSnippet;
         } catch (IllegalArgumentException e) {
             e.printStackTrace();
+            finish(); // 解析失败则结束活动
             return;
         }
 
         mPlayer = new MediaPlayer();
+        // 检查便签是否可见，可见则显示提醒对话框并播放声音
         if (DataUtils.visibleInNoteDatabase(getContentResolver(), mNoteId, Notes.TYPE_NOTE)) {
             showActionDialog();
             playAlarmSound();
@@ -83,55 +91,67 @@ public class AlarmAlertActivity extends Activity implements OnClickListener, OnD
         }
     }
 
+    /**
+     * 检查屏幕是否开启
+     * @return 屏幕开启返回true，否则返回false
+     */
     private boolean isScreenOn() {
         PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
         return pm.isScreenOn();
     }
 
+    /**
+     * 播放提醒声音
+     */
     private void playAlarmSound() {
+        // 获取默认闹钟铃声Uri
         Uri url = RingtoneManager.getActualDefaultRingtoneUri(this, RingtoneManager.TYPE_ALARM);
 
+        // 获取静音模式下影响的音频流设置
         int silentModeStreams = Settings.System.getInt(getContentResolver(),
                 Settings.System.MODE_RINGER_STREAMS_AFFECTED, 0);
 
+        // 设置音频流类型
         if ((silentModeStreams & (1 << AudioManager.STREAM_ALARM)) != 0) {
             mPlayer.setAudioStreamType(silentModeStreams);
         } else {
             mPlayer.setAudioStreamType(AudioManager.STREAM_ALARM);
         }
+
         try {
             mPlayer.setDataSource(this, url);
             mPlayer.prepare();
-            mPlayer.setLooping(true);
+            mPlayer.setLooping(true); // 设置循环播放
             mPlayer.start();
-        } catch (IllegalArgumentException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        } catch (SecurityException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        } catch (IllegalStateException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        } catch (IOException e) {
-            // TODO Auto-generated catch block
+        } catch (Exception e) {
             e.printStackTrace();
         }
     }
 
+    /**
+     * 显示提醒对话框
+     */
     private void showActionDialog() {
         AlertDialog.Builder dialog = new AlertDialog.Builder(this);
         dialog.setTitle(R.string.app_name);
-        dialog.setMessage(mSnippet);
-        dialog.setPositiveButton(R.string.notealert_ok, this);
+        dialog.setMessage(mSnippet); // 显示便签摘要
+        dialog.setPositiveButton(R.string.notealert_ok, this); // 确定按钮
+        // 如果屏幕已开启，显示进入便签编辑界面的按钮
         if (isScreenOn()) {
             dialog.setNegativeButton(R.string.notealert_enter, this);
         }
+        // 显示对话框并设置消失监听器
         dialog.show().setOnDismissListener(this);
     }
 
+    /**
+     * 对话框按钮点击回调
+     * @param dialog 对话框实例
+     * @param which 点击的按钮标识
+     */
     public void onClick(DialogInterface dialog, int which) {
         switch (which) {
+            // 点击"进入"按钮时，打开便签编辑界面
             case DialogInterface.BUTTON_NEGATIVE:
                 Intent intent = new Intent(this, NoteEditActivity.class);
                 intent.setAction(Intent.ACTION_VIEW);
@@ -143,11 +163,18 @@ public class AlarmAlertActivity extends Activity implements OnClickListener, OnD
         }
     }
 
+    /**
+     * 对话框消失回调
+     * @param dialog 对话框实例
+     */
     public void onDismiss(DialogInterface dialog) {
-        stopAlarmSound();
-        finish();
+        stopAlarmSound(); // 停止播放提醒声音
+        finish(); // 结束活动
     }
 
+    /**
+     * 停止播放提醒声音
+     */
     private void stopAlarmSound() {
         if (mPlayer != null) {
             mPlayer.stop();
@@ -155,4 +182,4 @@ public class AlarmAlertActivity extends Activity implements OnClickListener, OnD
             mPlayer = null;
         }
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/AlarmInitReceiver.java b/app/src/main/java/net/micode/notes/ui/AlarmInitReceiver.java
index f221202..be90fba 100644
--- a/app/src/main/java/net/micode/notes/ui/AlarmInitReceiver.java
+++ b/app/src/main/java/net/micode/notes/ui/AlarmInitReceiver.java
@@ -27,39 +27,52 @@ import android.database.Cursor;
 import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 
-
+/**
+ * 闹钟初始化广播接收器
+ * 用于在系统启动或相关事件触发时初始化便签的提醒闹钟
+ */
 public class AlarmInitReceiver extends BroadcastReceiver {
 
-    private static final String [] PROJECTION = new String [] {
-        NoteColumns.ID,
-        NoteColumns.ALERTED_DATE
+    // 数据库查询投影，获取便签ID和提醒时间
+    private static final String[] PROJECTION = new String[]{
+            NoteColumns.ID,
+            NoteColumns.ALERTED_DATE
     };
 
-    private static final int COLUMN_ID                = 0;
-    private static final int COLUMN_ALERTED_DATE      = 1;
+    // 投影列索引
+    private static final int COLUMN_ID = 0;
+    private static final int COLUMN_ALERTED_DATE = 1;
 
     @Override
     public void onReceive(Context context, Intent intent) {
-        long currentDate = System.currentTimeMillis();
+        long currentDate = System.currentTimeMillis(); // 获取当前时间
+
+        // 查询所有设置了提醒时间且未过期的普通便签
         Cursor c = context.getContentResolver().query(Notes.CONTENT_NOTE_URI,
                 PROJECTION,
                 NoteColumns.ALERTED_DATE + ">? AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE,
-                new String[] { String.valueOf(currentDate) },
+                new String[]{String.valueOf(currentDate)},
                 null);
 
         if (c != null) {
             if (c.moveToFirst()) {
                 do {
-                    long alertDate = c.getLong(COLUMN_ALERTED_DATE);
+                    long alertDate = c.getLong(COLUMN_ALERTED_DATE); // 获取便签提醒时间
+
+                    // 创建指向AlarmReceiver的Intent，并附加便签ID
                     Intent sender = new Intent(context, AlarmReceiver.class);
                     sender.setData(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, c.getLong(COLUMN_ID)));
+
+                    // 创建PendingIntent用于触发提醒
                     PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, sender, 0);
-                    AlarmManager alermManager = (AlarmManager) context
+
+                    // 获取AlarmManager实例并设置提醒闹钟
+                    AlarmManager alarmManager = (AlarmManager) context
                             .getSystemService(Context.ALARM_SERVICE);
-                    alermManager.set(AlarmManager.RTC_WAKEUP, alertDate, pendingIntent);
+                    alarmManager.set(AlarmManager.RTC_WAKEUP, alertDate, pendingIntent);
                 } while (c.moveToNext());
             }
             c.close();
         }
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/AlarmReceiver.java b/app/src/main/java/net/micode/notes/ui/AlarmReceiver.java
index 54e503b..da25692 100644
--- a/app/src/main/java/net/micode/notes/ui/AlarmReceiver.java
+++ b/app/src/main/java/net/micode/notes/ui/AlarmReceiver.java
@@ -20,11 +20,17 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 
+/**
+ * 闹钟提醒广播接收器
+ * 当便签提醒时间到达时触发，启动闹钟提醒活动
+ */
 public class AlarmReceiver extends BroadcastReceiver {
     @Override
     public void onReceive(Context context, Intent intent) {
+        // 创建并启动闹钟提醒活动
         intent.setClass(context, AlarmAlertActivity.class);
+        // 添加新任务标志，确保在新任务中启动活动
         intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         context.startActivity(intent);
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/DateTimePickerDialog.java b/app/src/main/java/net/micode/notes/ui/DateTimePickerDialog.java
index 2c47ba4..e78ba27 100644
--- a/app/src/main/java/net/micode/notes/ui/DateTimePickerDialog.java
+++ b/app/src/main/java/net/micode/notes/ui/DateTimePickerDialog.java
@@ -19,7 +19,6 @@ package net.micode.notes.ui;
 import java.util.Calendar;
 
 import net.micode.notes.R;
-import net.micode.notes.ui.DateTimePicker;
 import net.micode.notes.ui.DateTimePicker.OnDateTimeChangedListener;
 
 import android.app.AlertDialog;
@@ -29,24 +28,45 @@ import android.content.DialogInterface.OnClickListener;
 import android.text.format.DateFormat;
 import android.text.format.DateUtils;
 
+/**
+ * 日期时间选择对话框
+ * 封装了日期时间选择器，提供可视化的日期时间选择界面
+ */
 public class DateTimePickerDialog extends AlertDialog implements OnClickListener {
+    private Calendar mDate = Calendar.getInstance();           // 存储选择的日期时间
+    private boolean mIs24HourView;                              // 是否使用24小时制
+    private OnDateTimeSetListener mOnDateTimeSetListener;       // 选择完成后的回调接口
+    private DateTimePicker mDateTimePicker;                     // 日期时间选择器控件
 
-    private Calendar mDate = Calendar.getInstance();
-    private boolean mIs24HourView;
-    private OnDateTimeSetListener mOnDateTimeSetListener;
-    private DateTimePicker mDateTimePicker;
-
+    /**
+     * 日期时间设置回调接口
+     */
     public interface OnDateTimeSetListener {
+        /**
+         * 当日期时间设置完成时调用
+         * @param dialog 对话框实例
+         * @param date 选择的日期时间（毫秒值）
+         */
         void OnDateTimeSet(AlertDialog dialog, long date);
     }
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param date 初始日期时间（毫秒值）
+     */
     public DateTimePickerDialog(Context context, long date) {
         super(context);
+
+        // 初始化日期时间选择器控件
         mDateTimePicker = new DateTimePicker(context);
         setView(mDateTimePicker);
+
+        // 设置日期时间变化监听器
         mDateTimePicker.setOnDateTimeChangedListener(new OnDateTimeChangedListener() {
             public void onDateTimeChanged(DateTimePicker view, int year, int month,
-                    int dayOfMonth, int hourOfDay, int minute) {
+                                          int dayOfMonth, int hourOfDay, int minute) {
+                // 更新日历对象并刷新标题
                 mDate.set(Calendar.YEAR, year);
                 mDate.set(Calendar.MONTH, month);
                 mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
@@ -55,36 +75,59 @@ public class DateTimePickerDialog extends AlertDialog implements OnClickListener
                 updateTitle(mDate.getTimeInMillis());
             }
         });
+
+        // 初始化日期时间
         mDate.setTimeInMillis(date);
         mDate.set(Calendar.SECOND, 0);
         mDateTimePicker.setCurrentDate(mDate.getTimeInMillis());
+
+        // 设置对话框按钮
         setButton(context.getString(R.string.datetime_dialog_ok), this);
-        setButton2(context.getString(R.string.datetime_dialog_cancel), (OnClickListener)null);
+        setButton2(context.getString(R.string.datetime_dialog_cancel), (OnClickListener) null);
+
+        // 设置时间显示格式（24小时制或12小时制）
         set24HourView(DateFormat.is24HourFormat(this.getContext()));
         updateTitle(mDate.getTimeInMillis());
     }
 
+    /**
+     * 设置时间显示格式
+     * @param is24HourView true表示24小时制，false表示12小时制
+     */
     public void set24HourView(boolean is24HourView) {
         mIs24HourView = is24HourView;
     }
 
+    /**
+     * 设置日期时间选择完成后的回调
+     * @param callBack 回调接口实例
+     */
     public void setOnDateTimeSetListener(OnDateTimeSetListener callBack) {
         mOnDateTimeSetListener = callBack;
     }
 
+    /**
+     * 更新对话框标题为当前选择的日期时间
+     * @param date 日期时间（毫秒值）
+     */
     private void updateTitle(long date) {
         int flag =
-            DateUtils.FORMAT_SHOW_YEAR |
-            DateUtils.FORMAT_SHOW_DATE |
-            DateUtils.FORMAT_SHOW_TIME;
+                DateUtils.FORMAT_SHOW_YEAR |
+                        DateUtils.FORMAT_SHOW_DATE |
+                        DateUtils.FORMAT_SHOW_TIME;
         flag |= mIs24HourView ? DateUtils.FORMAT_24HOUR : DateUtils.FORMAT_24HOUR;
         setTitle(DateUtils.formatDateTime(this.getContext(), date, flag));
     }
 
+    /**
+     * 对话框按钮点击回调
+     * @param arg0 对话框实例
+     * @param arg1 点击的按钮标识
+     */
     public void onClick(DialogInterface arg0, int arg1) {
         if (mOnDateTimeSetListener != null) {
+            // 触发日期时间设置完成回调
             mOnDateTimeSetListener.OnDateTimeSet(this, mDate.getTimeInMillis());
         }
     }
-
 }
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/DropdownMenu.java b/app/src/main/java/net/micode/notes/ui/DropdownMenu.java
index 613dc74..6d11111 100644
--- a/app/src/main/java/net/micode/notes/ui/DropdownMenu.java
+++ b/app/src/main/java/net/micode/notes/ui/DropdownMenu.java
@@ -27,17 +27,31 @@ import android.widget.PopupMenu.OnMenuItemClickListener;
 
 import net.micode.notes.R;
 
+/**
+ * 下拉菜单工具类
+ * 封装PopupMenu实现下拉菜单功能，可绑定到按钮并设置菜单项点击事件
+ */
 public class DropdownMenu {
-    private Button mButton;
-    private PopupMenu mPopupMenu;
-    private Menu mMenu;
+    private Button mButton;                // 触发下拉菜单的按钮
+    private PopupMenu mPopupMenu;          // 下拉菜单实例
+    private Menu mMenu;                    // 菜单实例
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param button 触发下拉菜单的按钮
+     * @param menuId 菜单资源ID
+     */
     public DropdownMenu(Context context, Button button, int menuId) {
         mButton = button;
+        // 设置按钮背景为下拉图标
         mButton.setBackgroundResource(R.drawable.dropdown_icon);
+        // 创建PopupMenu实例并关联按钮
         mPopupMenu = new PopupMenu(context, mButton);
         mMenu = mPopupMenu.getMenu();
+        // 从资源文件加载菜单
         mPopupMenu.getMenuInflater().inflate(menuId, mMenu);
+        // 设置按钮点击事件，点击时显示下拉菜单
         mButton.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 mPopupMenu.show();
@@ -45,17 +59,30 @@ public class DropdownMenu {
         });
     }
 
+    /**
+     * 设置下拉菜单项点击监听器
+     * @param listener 菜单项点击监听器
+     */
     public void setOnDropdownMenuItemClickListener(OnMenuItemClickListener listener) {
         if (mPopupMenu != null) {
             mPopupMenu.setOnMenuItemClickListener(listener);
         }
     }
 
+    /**
+     * 根据ID查找菜单项
+     * @param id 菜单项ID
+     * @return 对应的菜单项，未找到返回null
+     */
     public MenuItem findItem(int id) {
         return mMenu.findItem(id);
     }
 
+    /**
+     * 设置按钮标题
+     * @param title 标题文本
+     */
     public void setTitle(CharSequence title) {
         mButton.setText(title);
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/FoldersListAdapter.java b/app/src/main/java/net/micode/notes/ui/FoldersListAdapter.java
index 96b77da..b7ab79d 100644
--- a/app/src/main/java/net/micode/notes/ui/FoldersListAdapter.java
+++ b/app/src/main/java/net/micode/notes/ui/FoldersListAdapter.java
@@ -28,53 +28,95 @@ import net.micode.notes.R;
 import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 
-
+/**
+ * 文件夹列表适配器
+ * 用于将文件夹数据绑定到列表视图，支持文件夹名称的显示和自定义
+ */
 public class FoldersListAdapter extends CursorAdapter {
-    public static final String [] PROJECTION = {
-        NoteColumns.ID,
-        NoteColumns.SNIPPET
+    // 数据库查询投影，获取文件夹ID和名称
+    public static final String[] PROJECTION = {
+            NoteColumns.ID,
+            NoteColumns.SNIPPET
     };
 
+    // 投影列索引
     public static final int ID_COLUMN   = 0;
     public static final int NAME_COLUMN = 1;
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param c 包含文件夹数据的Cursor
+     */
     public FoldersListAdapter(Context context, Cursor c) {
         super(context, c);
-        // TODO Auto-generated constructor stub
     }
 
+    /**
+     * 创建列表项视图
+     * @param context 上下文
+     * @param cursor 数据Cursor
+     * @param parent 父视图组
+     * @return 新创建的FolderListItem视图
+     */
     @Override
     public View newView(Context context, Cursor cursor, ViewGroup parent) {
         return new FolderListItem(context);
     }
 
+    /**
+     * 绑定数据到视图
+     * @param view 列表项视图
+     * @param context 上下文
+     * @param cursor 数据Cursor
+     */
     @Override
     public void bindView(View view, Context context, Cursor cursor) {
         if (view instanceof FolderListItem) {
+            // 处理根文件夹的特殊显示名称
             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);
         }
     }
 
+    /**
+     * 获取指定位置的文件夹名称
+     * @param context 上下文
+     * @param position 列表位置
+     * @return 文件夹名称
+     */
     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);
     }
 
+    /**
+     * 文件夹列表项视图
+     * 自定义LinearLayout，包含文件夹名称文本显示
+     */
     private class FolderListItem extends LinearLayout {
-        private TextView mName;
+        private TextView mName;  // 文件夹名称文本视图
 
+        /**
+         * 构造函数
+         * @param context 上下文
+         */
         public FolderListItem(Context context) {
             super(context);
+            // 加载列表项布局
             inflate(context, R.layout.folder_list_item, this);
+            // 获取名称文本视图
             mName = (TextView) findViewById(R.id.tv_folder_name);
         }
 
+        /**
+         * 绑定文件夹名称到视图
+         * @param name 文件夹名称
+         */
         public void bind(String name) {
             mName.setText(name);
         }
     }
-
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/NoteEditText.java b/app/src/main/java/net/micode/notes/ui/NoteEditText.java
index 2afe2a8..b31775d 100644
--- a/app/src/main/java/net/micode/notes/ui/NoteEditText.java
+++ b/app/src/main/java/net/micode/notes/ui/NoteEditText.java
@@ -37,15 +37,21 @@ import net.micode.notes.R;
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * 笔记编辑文本框
+ * 扩展自EditText，提供增强的编辑功能和链接处理能力
+ */
 public class NoteEditText extends EditText {
     private static final String TAG = "NoteEditText";
-    private int mIndex;
-    private int mSelectionStartBeforeDelete;
+    private int mIndex;                     // 文本框在列表中的索引
+    private int mSelectionStartBeforeDelete; // 删除操作前的光标位置
 
+    // 支持的链接协议
     private static final String SCHEME_TEL = "tel:" ;
     private static final String SCHEME_HTTP = "http:" ;
     private static final String SCHEME_EMAIL = "mailto:" ;
 
+    // 链接协议与菜单资源ID映射
     private static final Map<String, Integer> sSchemaActionResMap = new HashMap<String, Integer>();
     static {
         sSchemaActionResMap.put(SCHEME_TEL, R.string.note_link_tel);
@@ -54,56 +60,89 @@ public class NoteEditText extends EditText {
     }
 
     /**
-     * Call by the {@link NoteEditActivity} to delete or add edit text
+     * 文本框变化监听器接口
+     * 用于与父Activity通信，处理文本框的添加、删除和文本变化
      */
     public interface OnTextViewChangeListener {
         /**
-         * Delete current edit text when {@link KeyEvent#KEYCODE_DEL} happens
-         * and the text is null
+         * 当按下删除键且文本为空时，删除当前文本框
+         * @param index 当前文本框索引
+         * @param text 当前文本内容
          */
         void onEditTextDelete(int index, String text);
 
         /**
-         * Add edit text after current edit text when {@link KeyEvent#KEYCODE_ENTER}
-         * happen
+         * 当按下回车键时，在当前文本框后添加新文本框
+         * @param index 新文本框的索引
+         * @param text 剩余未处理的文本内容
          */
         void onEditTextEnter(int index, String text);
 
         /**
-         * Hide or show item option when text change
+         * 当文本变化时，隐藏或显示选项
+         * @param index 当前文本框索引
+         * @param hasText 是否有文本内容
          */
         void onTextChange(int index, boolean hasText);
     }
 
-    private OnTextViewChangeListener mOnTextViewChangeListener;
+    private OnTextViewChangeListener mOnTextViewChangeListener; // 监听器实例
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     */
     public NoteEditText(Context context) {
         super(context, null);
         mIndex = 0;
     }
 
+    /**
+     * 设置文本框索引
+     * @param index 索引值
+     */
     public void setIndex(int index) {
         mIndex = index;
     }
 
+    /**
+     * 设置文本框变化监听器
+     * @param listener 监听器实例
+     */
     public void setOnTextViewChangeListener(OnTextViewChangeListener listener) {
         mOnTextViewChangeListener = listener;
     }
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param attrs 属性集
+     */
     public NoteEditText(Context context, AttributeSet attrs) {
         super(context, attrs, android.R.attr.editTextStyle);
     }
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param attrs 属性集
+     * @param defStyle 默认样式
+     */
     public NoteEditText(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
-        // TODO Auto-generated constructor stub
     }
 
+    /**
+     * 处理触摸事件
+     * 确保点击时正确设置光标位置
+     * @param event 触摸事件
+     * @return 是否处理该事件
+     */
     @Override
     public boolean onTouchEvent(MotionEvent event) {
         switch (event.getAction()) {
             case MotionEvent.ACTION_DOWN:
-
+                // 计算点击位置对应的文本偏移量并设置光标
                 int x = (int) event.getX();
                 int y = (int) event.getY();
                 x -= getTotalPaddingLeft();
@@ -121,15 +160,23 @@ public class NoteEditText extends EditText {
         return super.onTouchEvent(event);
     }
 
+    /**
+     * 处理按键按下事件
+     * @param keyCode 按键码
+     * @param event 按键事件
+     * @return 是否处理该事件
+     */
     @Override
     public boolean onKeyDown(int keyCode, KeyEvent event) {
         switch (keyCode) {
             case KeyEvent.KEYCODE_ENTER:
+                // 回车键由onKeyUp处理
                 if (mOnTextViewChangeListener != null) {
                     return false;
                 }
                 break;
             case KeyEvent.KEYCODE_DEL:
+                // 记录删除前的光标位置
                 mSelectionStartBeforeDelete = getSelectionStart();
                 break;
             default:
@@ -138,12 +185,20 @@ public class NoteEditText extends EditText {
         return super.onKeyDown(keyCode, event);
     }
 
+    /**
+     * 处理按键释放事件
+     * @param keyCode 按键码
+     * @param event 按键事件
+     * @return 是否处理该事件
+     */
     @Override
     public boolean onKeyUp(int keyCode, KeyEvent event) {
         switch(keyCode) {
             case KeyEvent.KEYCODE_DEL:
+                // 处理删除操作
                 if (mOnTextViewChangeListener != null) {
                     if (0 == mSelectionStartBeforeDelete && mIndex != 0) {
+                        // 光标在文本开头且不是第一个文本框时，触发删除
                         mOnTextViewChangeListener.onEditTextDelete(mIndex, getText().toString());
                         return true;
                     }
@@ -152,10 +207,12 @@ public class NoteEditText extends EditText {
                 }
                 break;
             case KeyEvent.KEYCODE_ENTER:
+                // 处理回车键
                 if (mOnTextViewChangeListener != null) {
                     int selectionStart = getSelectionStart();
                     String text = getText().subSequence(selectionStart, length()).toString();
                     setText(getText().subSequence(0, selectionStart));
+                    // 在当前位置后插入新文本框
                     mOnTextViewChangeListener.onEditTextEnter(mIndex + 1, text);
                 } else {
                     Log.d(TAG, "OnTextViewChangeListener was not seted");
@@ -167,18 +224,31 @@ public class NoteEditText extends EditText {
         return super.onKeyUp(keyCode, event);
     }
 
+    /**
+     * 焦点变化回调
+     * @param focused 是否获得焦点
+     * @param direction 焦点移动方向
+     * @param previouslyFocusedRect 之前焦点的矩形区域
+     */
     @Override
     protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) {
         if (mOnTextViewChangeListener != null) {
             if (!focused && TextUtils.isEmpty(getText())) {
+                // 失去焦点且文本为空时
                 mOnTextViewChangeListener.onTextChange(mIndex, false);
             } else {
+                // 有焦点或有文本时
                 mOnTextViewChangeListener.onTextChange(mIndex, true);
             }
         }
         super.onFocusChanged(focused, direction, previouslyFocusedRect);
     }
 
+    /**
+     * 创建上下文菜单
+     * 处理链接长按的上下文菜单
+     * @param menu 上下文菜单
+     */
     @Override
     protected void onCreateContextMenu(ContextMenu menu) {
         if (getText() instanceof Spanned) {
@@ -188,8 +258,10 @@ public class NoteEditText extends EditText {
             int min = Math.min(selStart, selEnd);
             int max = Math.max(selStart, selEnd);
 
+            // 获取选中区域的URLSpan
             final URLSpan[] urls = ((Spanned) getText()).getSpans(min, max, URLSpan.class);
             if (urls.length == 1) {
+                // 根据链接协议设置菜单项
                 int defaultResId = 0;
                 for(String schema: sSchemaActionResMap.keySet()) {
                     if(urls[0].getURL().indexOf(schema) >= 0) {
@@ -202,10 +274,11 @@ public class NoteEditText extends EditText {
                     defaultResId = R.string.note_link_other;
                 }
 
+                // 添加菜单项并设置点击事件
                 menu.add(0, 0, 0, defaultResId).setOnMenuItemClickListener(
                         new OnMenuItemClickListener() {
                             public boolean onMenuItemClick(MenuItem item) {
-                                // goto a new intent
+                                // 调用URLSpan的点击处理
                                 urls[0].onClick(NoteEditText.this);
                                 return true;
                             }
@@ -214,4 +287,4 @@ public class NoteEditText extends EditText {
         }
         super.onCreateContextMenu(menu);
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/NoteItemData.java b/app/src/main/java/net/micode/notes/ui/NoteItemData.java
index 0f5a878..c1953d1 100644
--- a/app/src/main/java/net/micode/notes/ui/NoteItemData.java
+++ b/app/src/main/java/net/micode/notes/ui/NoteItemData.java
@@ -25,58 +25,71 @@ import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.tool.DataUtils;
 
-
+/**
+ * 便签项数据模型类
+ * 封装便签列表项的所有数据，包括便签基本信息和列表位置信息
+ */
 public class NoteItemData {
-    static final String [] PROJECTION = new String [] {
-        NoteColumns.ID,
-        NoteColumns.ALERTED_DATE,
-        NoteColumns.BG_COLOR_ID,
-        NoteColumns.CREATED_DATE,
-        NoteColumns.HAS_ATTACHMENT,
-        NoteColumns.MODIFIED_DATE,
-        NoteColumns.NOTES_COUNT,
-        NoteColumns.PARENT_ID,
-        NoteColumns.SNIPPET,
-        NoteColumns.TYPE,
-        NoteColumns.WIDGET_ID,
-        NoteColumns.WIDGET_TYPE,
+    // 数据库查询投影，获取便签的各项属性
+    static final String[] PROJECTION = new String[]{
+            NoteColumns.ID,                // 便签ID
+            NoteColumns.ALERTED_DATE,      // 提醒日期
+            NoteColumns.BG_COLOR_ID,       // 背景颜色ID
+            NoteColumns.CREATED_DATE,      // 创建日期
+            NoteColumns.HAS_ATTACHMENT,    // 是否有附件
+            NoteColumns.MODIFIED_DATE,     // 修改日期
+            NoteColumns.NOTES_COUNT,       // 子便签数量（用于文件夹）
+            NoteColumns.PARENT_ID,         // 父文件夹ID
+            NoteColumns.SNIPPET,           // 便签摘要
+            NoteColumns.TYPE,              // 便签类型
+            NoteColumns.WIDGET_ID,         // 小部件ID
+            NoteColumns.WIDGET_TYPE,       // 小部件类型
     };
 
-    private static final int ID_COLUMN                    = 0;
-    private static final int ALERTED_DATE_COLUMN          = 1;
-    private static final int BG_COLOR_ID_COLUMN           = 2;
-    private static final int CREATED_DATE_COLUMN          = 3;
-    private static final int HAS_ATTACHMENT_COLUMN        = 4;
-    private static final int MODIFIED_DATE_COLUMN         = 5;
-    private static final int NOTES_COUNT_COLUMN           = 6;
-    private static final int PARENT_ID_COLUMN             = 7;
-    private static final int SNIPPET_COLUMN               = 8;
-    private static final int TYPE_COLUMN                  = 9;
-    private static final int WIDGET_ID_COLUMN             = 10;
-    private static final int WIDGET_TYPE_COLUMN           = 11;
-
-    private long mId;
-    private long mAlertDate;
-    private int mBgColorId;
-    private long mCreatedDate;
-    private boolean mHasAttachment;
-    private long mModifiedDate;
-    private int mNotesCount;
-    private long mParentId;
-    private String mSnippet;
-    private int mType;
-    private int mWidgetId;
-    private int mWidgetType;
-    private String mName;
-    private String mPhoneNumber;
-
-    private boolean mIsLastItem;
-    private boolean mIsFirstItem;
-    private boolean mIsOnlyOneItem;
-    private boolean mIsOneNoteFollowingFolder;
-    private boolean mIsMultiNotesFollowingFolder;
-
+    // 投影列索引
+    private static final int ID_COLUMN = 0;
+    private static final int ALERTED_DATE_COLUMN = 1;
+    private static final int BG_COLOR_ID_COLUMN = 2;
+    private static final int CREATED_DATE_COLUMN = 3;
+    private static final int HAS_ATTACHMENT_COLUMN = 4;
+    private static final int MODIFIED_DATE_COLUMN = 5;
+    private static final int NOTES_COUNT_COLUMN = 6;
+    private static final int PARENT_ID_COLUMN = 7;
+    private static final int SNIPPET_COLUMN = 8;
+    private static final int TYPE_COLUMN = 9;
+    private static final int WIDGET_ID_COLUMN = 10;
+    private static final int WIDGET_TYPE_COLUMN = 11;
+
+    // 便签基本信息
+    private long mId;                  // 便签ID
+    private long mAlertDate;           // 提醒日期
+    private int mBgColorId;            // 背景颜色ID
+    private long mCreatedDate;         // 创建日期
+    private boolean mHasAttachment;    // 是否有附件
+    private long mModifiedDate;        // 修改日期
+    private int mNotesCount;           // 子便签数量（用于文件夹）
+    private long mParentId;            // 父文件夹ID
+    private String mSnippet;           // 便签摘要
+    private int mType;                 // 便签类型
+    private int mWidgetId;             // 小部件ID
+    private int mWidgetType;           // 小部件类型
+    private String mName;              // 联系人名称（用于通话记录便签）
+    private String mPhoneNumber;       // 电话号码（用于通话记录便签）
+
+    // 列表位置信息
+    private boolean mIsLastItem;       // 是否为列表最后一项
+    private boolean mIsFirstItem;      // 是否为列表第一项
+    private boolean mIsOnlyOneItem;    // 是否为列表唯一一项
+    private boolean mIsOneNoteFollowingFolder; // 是否为文件夹后的单个便签
+    private boolean mIsMultiNotesFollowingFolder; // 是否为文件夹后的多个便签
+
+    /**
+     * 构造函数
+     * @param context 上下文
+     * @param cursor 包含便签数据的Cursor
+     */
     public NoteItemData(Context context, Cursor cursor) {
+        // 从Cursor中获取便签基本信息
         mId = cursor.getLong(ID_COLUMN);
         mAlertDate = cursor.getLong(ALERTED_DATE_COLUMN);
         mBgColorId = cursor.getInt(BG_COLOR_ID_COLUMN);
@@ -86,6 +99,7 @@ public class NoteItemData {
         mNotesCount = cursor.getInt(NOTES_COUNT_COLUMN);
         mParentId = cursor.getLong(PARENT_ID_COLUMN);
         mSnippet = cursor.getString(SNIPPET_COLUMN);
+        // 移除便签摘要中的复选框标记
         mSnippet = mSnippet.replace(NoteEditActivity.TAG_CHECKED, "").replace(
                 NoteEditActivity.TAG_UNCHECKED, "");
         mType = cursor.getInt(TYPE_COLUMN);
@@ -93,6 +107,7 @@ public class NoteItemData {
         mWidgetType = cursor.getInt(WIDGET_TYPE_COLUMN);
 
         mPhoneNumber = "";
+        // 处理通话记录便签，获取电话号码和联系人名称
         if (mParentId == Notes.ID_CALL_RECORD_FOLDER) {
             mPhoneNumber = DataUtils.getCallNumberByNoteId(context.getContentResolver(), mId);
             if (!TextUtils.isEmpty(mPhoneNumber)) {
@@ -106,9 +121,14 @@ public class NoteItemData {
         if (mName == null) {
             mName = "";
         }
+        // 检查便签在列表中的位置信息
         checkPostion(cursor);
     }
 
+    /**
+     * 检查便签在列表中的位置
+     * @param cursor 数据Cursor
+     */
     private void checkPostion(Cursor cursor) {
         mIsLastItem = cursor.isLast() ? true : false;
         mIsFirstItem = cursor.isFirst() ? true : false;
@@ -116,9 +136,11 @@ public class NoteItemData {
         mIsMultiNotesFollowingFolder = false;
         mIsOneNoteFollowingFolder = false;
 
+        // 检查是否为文件夹后的便签
         if (mType == Notes.TYPE_NOTE && !mIsFirstItem) {
             int position = cursor.getPosition();
             if (cursor.moveToPrevious()) {
+                // 前一项是文件夹或系统项
                 if (cursor.getInt(TYPE_COLUMN) == Notes.TYPE_FOLDER
                         || cursor.getInt(TYPE_COLUMN) == Notes.TYPE_SYSTEM) {
                     if (cursor.getCount() > (position + 1)) {
@@ -127,6 +149,7 @@ public class NoteItemData {
                         mIsOneNoteFollowingFolder = true;
                     }
                 }
+                // 恢复Cursor位置
                 if (!cursor.moveToNext()) {
                     throw new IllegalStateException("cursor move to previous but can't move back");
                 }
@@ -134,91 +157,180 @@ public class NoteItemData {
         }
     }
 
+    /**
+     * 判断是否为文件夹后的单个便签
+     * @return true表示是文件夹后的单个便签
+     */
     public boolean isOneFollowingFolder() {
         return mIsOneNoteFollowingFolder;
     }
 
+    /**
+     * 判断是否为文件夹后的多个便签
+     * @return true表示是文件夹后的多个便签
+     */
     public boolean isMultiFollowingFolder() {
         return mIsMultiNotesFollowingFolder;
     }
 
+    /**
+     * 判断是否为列表最后一项
+     * @return true表示是列表最后一项
+     */
     public boolean isLast() {
         return mIsLastItem;
     }
 
+    /**
+     * 获取通话记录便签的联系人名称
+     * @return 联系人名称或电话号码
+     */
     public String getCallName() {
         return mName;
     }
 
+    /**
+     * 判断是否为列表第一项
+     * @return true表示是列表第一项
+     */
     public boolean isFirst() {
         return mIsFirstItem;
     }
 
+    /**
+     * 判断是否为列表唯一一项
+     * @return true表示是列表唯一一项
+     */
     public boolean isSingle() {
         return mIsOnlyOneItem;
     }
 
+    /**
+     * 获取便签ID
+     * @return 便签ID
+     */
     public long getId() {
         return mId;
     }
 
+    /**
+     * 获取提醒日期
+     * @return 提醒日期（毫秒值）
+     */
     public long getAlertDate() {
         return mAlertDate;
     }
 
+    /**
+     * 获取创建日期
+     * @return 创建日期（毫秒值）
+     */
     public long getCreatedDate() {
         return mCreatedDate;
     }
 
+    /**
+     * 判断是否有附件
+     * @return true表示有附件
+     */
     public boolean hasAttachment() {
         return mHasAttachment;
     }
 
+    /**
+     * 获取修改日期
+     * @return 修改日期（毫秒值）
+     */
     public long getModifiedDate() {
         return mModifiedDate;
     }
 
+    /**
+     * 获取背景颜色ID
+     * @return 背景颜色ID
+     */
     public int getBgColorId() {
         return mBgColorId;
     }
 
+    /**
+     * 获取父文件夹ID
+     * @return 父文件夹ID
+     */
     public long getParentId() {
         return mParentId;
     }
 
+    /**
+     * 获取子便签数量（用于文件夹）
+     * @return 子便签数量
+     */
     public int getNotesCount() {
         return mNotesCount;
     }
 
-    public long getFolderId () {
+    /**
+     * 获取文件夹ID（与父文件夹ID相同）
+     * @return 文件夹ID
+     */
+    public long getFolderId() {
         return mParentId;
     }
 
+    /**
+     * 获取便签类型
+     * @return 便签类型
+     */
     public int getType() {
         return mType;
     }
 
+    /**
+     * 获取小部件类型
+     * @return 小部件类型
+     */
     public int getWidgetType() {
         return mWidgetType;
     }
 
+    /**
+     * 获取小部件ID
+     * @return 小部件ID
+     */
     public int getWidgetId() {
         return mWidgetId;
     }
 
+    /**
+     * 获取便签摘要
+     * @return 便签摘要
+     */
     public String getSnippet() {
         return mSnippet;
     }
 
+    /**
+     * 判断是否设置了提醒
+     * @return true表示设置了提醒
+     */
     public boolean hasAlert() {
         return (mAlertDate > 0);
     }
 
+    /**
+     * 判断是否为通话记录便签
+     * @return true表示是通话记录便签
+     */
     public boolean isCallRecord() {
         return (mParentId == Notes.ID_CALL_RECORD_FOLDER && !TextUtils.isEmpty(mPhoneNumber));
     }
 
+    /**
+     * 从Cursor中获取便签类型
+     * @param cursor 数据Cursor
+     * @return 便签类型
+     */
     public static int getNoteType(Cursor cursor) {
         return cursor.getInt(TYPE_COLUMN);
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/NotesListAdapter.java b/app/src/main/java/net/micode/notes/ui/NotesListAdapter.java
index 0d67aba..3c0366c 100644
--- a/app/src/main/java/net/micode/notes/ui/NotesListAdapter.java
+++ b/app/src/main/java/net/micode/notes/ui/NotesListAdapter.java
@@ -30,19 +30,30 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 
-
+/**
+ * 便签列表适配器
+ * 用于将便签数据绑定到列表视图，支持选择模式和便签项管理
+ */
 public class NotesListAdapter extends CursorAdapter {
     private static final String TAG = "NotesListAdapter";
-    private Context mContext;
-    private HashMap<Integer, Boolean> mSelectedIndex;
-    private int mNotesCount;
-    private boolean mChoiceMode;
-
+    private Context mContext;                        // 上下文
+    private HashMap<Integer, Boolean> mSelectedIndex; // 选中项索引映射
+    private int mNotesCount;                         // 便签项数量
+    private boolean mChoiceMode;                     // 是否为选择模式
+
+    /**
+     * 桌面小部件属性类
+     * 存储小部件ID和类型
+     */
     public static class AppWidgetAttribute {
-        public int widgetId;
-        public int widgetType;
-    };
+        public int widgetId;     // 小部件ID
+        public int widgetType;   // 小部件类型
+    }
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     */
     public NotesListAdapter(Context context) {
         super(context, null);
         mSelectedIndex = new HashMap<Integer, Boolean>();
@@ -50,38 +61,70 @@ public class NotesListAdapter extends CursorAdapter {
         mNotesCount = 0;
     }
 
+    /**
+     * 创建列表项视图
+     * @param context 上下文
+     * @param cursor 数据Cursor
+     * @param parent 父视图组
+     * @return 新创建的NotesListItem视图
+     */
     @Override
     public View newView(Context context, Cursor cursor, ViewGroup parent) {
         return new NotesListItem(context);
     }
 
+    /**
+     * 绑定数据到视图
+     * @param view 列表项视图
+     * @param context 上下文
+     * @param cursor 数据Cursor
+     */
     @Override
     public void bindView(View view, Context context, Cursor cursor) {
         if (view instanceof NotesListItem) {
+            // 创建便签项数据模型并绑定到视图
             NoteItemData itemData = new NoteItemData(context, cursor);
             ((NotesListItem) view).bind(context, itemData, mChoiceMode,
                     isSelectedItem(cursor.getPosition()));
         }
     }
 
+    /**
+     * 设置指定位置项的选中状态
+     * @param position 位置索引
+     * @param checked 选中状态
+     */
     public void setCheckedItem(final int position, final boolean checked) {
         mSelectedIndex.put(position, checked);
-        notifyDataSetChanged();
+        notifyDataSetChanged(); // 通知适配器数据已更改
     }
 
+    /**
+     * 判断是否处于选择模式
+     * @return true表示处于选择模式
+     */
     public boolean isInChoiceMode() {
         return mChoiceMode;
     }
 
+    /**
+     * 设置选择模式
+     * @param mode 选择模式状态
+     */
     public void setChoiceMode(boolean mode) {
-        mSelectedIndex.clear();
+        mSelectedIndex.clear(); // 清除已选状态
         mChoiceMode = mode;
     }
 
+    /**
+     * 全选或取消全选
+     * @param checked 选中状态
+     */
     public void selectAll(boolean checked) {
         Cursor cursor = getCursor();
         for (int i = 0; i < getCount(); i++) {
             if (cursor.moveToPosition(i)) {
+                // 仅处理便签类型（非文件夹）
                 if (NoteItemData.getNoteType(cursor) == Notes.TYPE_NOTE) {
                     setCheckedItem(i, checked);
                 }
@@ -89,6 +132,10 @@ public class NotesListAdapter extends CursorAdapter {
         }
     }
 
+    /**
+     * 获取选中项的ID集合
+     * @return 选中项ID的HashSet
+     */
     public HashSet<Long> getSelectedItemIds() {
         HashSet<Long> itemSet = new HashSet<Long>();
         for (Integer position : mSelectedIndex.keySet()) {
@@ -101,10 +148,13 @@ public class NotesListAdapter extends CursorAdapter {
                 }
             }
         }
-
         return itemSet;
     }
 
+    /**
+     * 获取选中的小部件属性集合
+     * @return 小部件属性的HashSet
+     */
     public HashSet<AppWidgetAttribute> getSelectedWidget() {
         HashSet<AppWidgetAttribute> itemSet = new HashSet<AppWidgetAttribute>();
         for (Integer position : mSelectedIndex.keySet()) {
@@ -116,9 +166,6 @@ public class NotesListAdapter extends CursorAdapter {
                     widget.widgetId = item.getWidgetId();
                     widget.widgetType = item.getWidgetType();
                     itemSet.add(widget);
-                    /**
-                     * Don't close cursor here, only the adapter could close it
-                     */
                 } else {
                     Log.e(TAG, "Invalid cursor");
                     return null;
@@ -128,6 +175,10 @@ public class NotesListAdapter extends CursorAdapter {
         return itemSet;
     }
 
+    /**
+     * 获取选中项的数量
+     * @return 选中项数量
+     */
     public int getSelectedCount() {
         Collection<Boolean> values = mSelectedIndex.values();
         if (null == values) {
@@ -143,11 +194,20 @@ public class NotesListAdapter extends CursorAdapter {
         return count;
     }
 
+    /**
+     * 判断是否全选
+     * @return true表示全选
+     */
     public boolean isAllSelected() {
         int checkedCount = getSelectedCount();
         return (checkedCount != 0 && checkedCount == mNotesCount);
     }
 
+    /**
+     * 判断指定位置项是否选中
+     * @param position 位置索引
+     * @return true表示已选中
+     */
     public boolean isSelectedItem(final int position) {
         if (null == mSelectedIndex.get(position)) {
             return false;
@@ -155,18 +215,28 @@ public class NotesListAdapter extends CursorAdapter {
         return mSelectedIndex.get(position);
     }
 
+    /**
+     * 内容变化回调
+     */
     @Override
     protected void onContentChanged() {
         super.onContentChanged();
-        calcNotesCount();
+        calcNotesCount(); // 重新计算便签数量
     }
 
+    /**
+     * 更换Cursor时回调
+     * @param cursor 新Cursor
+     */
     @Override
     public void changeCursor(Cursor cursor) {
         super.changeCursor(cursor);
-        calcNotesCount();
+        calcNotesCount(); // 重新计算便签数量
     }
 
+    /**
+     * 计算便签项数量（仅统计便签类型）
+     */
     private void calcNotesCount() {
         mNotesCount = 0;
         for (int i = 0; i < getCount(); i++) {
@@ -179,4 +249,4 @@ public class NotesListAdapter extends CursorAdapter {
             }
         }
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/NotesListItem.java b/app/src/main/java/net/micode/notes/ui/NotesListItem.java
index 1221e80..74858eb 100644
--- a/app/src/main/java/net/micode/notes/ui/NotesListItem.java
+++ b/app/src/main/java/net/micode/notes/ui/NotesListItem.java
@@ -29,18 +29,27 @@ import net.micode.notes.data.Notes;
 import net.micode.notes.tool.DataUtils;
 import net.micode.notes.tool.ResourceParser.NoteItemBgResources;
 
-
+/**
+ * 便签列表项视图
+ * 自定义LinearLayout，用于展示便签列表中的单个项，支持不同类型便签的差异化显示
+ */
 public class NotesListItem extends LinearLayout {
-    private ImageView mAlert;
-    private TextView mTitle;
-    private TextView mTime;
-    private TextView mCallName;
-    private NoteItemData mItemData;
-    private CheckBox mCheckBox;
+    private ImageView mAlert;      // 提醒图标
+    private TextView mTitle;       // 便签标题/摘要
+    private TextView mTime;        // 时间文本
+    private TextView mCallName;    // 通话记录联系人名称
+    private NoteItemData mItemData;// 便签项数据模型
+    private CheckBox mCheckBox;    // 选择模式下的复选框
 
+    /**
+     * 构造函数
+     * @param context 上下文
+     */
     public NotesListItem(Context context) {
         super(context);
+        // 加载便签列表项布局
         inflate(context, R.layout.note_item, this);
+        // 获取布局中的视图控件
         mAlert = (ImageView) findViewById(R.id.iv_alert_icon);
         mTitle = (TextView) findViewById(R.id.tv_title);
         mTime = (TextView) findViewById(R.id.tv_time);
@@ -48,7 +57,15 @@ public class NotesListItem extends LinearLayout {
         mCheckBox = (CheckBox) findViewById(android.R.id.checkbox);
     }
 
+    /**
+     * 绑定数据到视图
+     * @param context 上下文
+     * @param data 便签项数据模型
+     * @param choiceMode 是否为选择模式
+     * @param checked 选中状态（选择模式下）
+     */
     public void bind(Context context, NoteItemData data, boolean choiceMode, boolean checked) {
+        // 处理选择模式下的复选框显示
         if (choiceMode && data.getType() == Notes.TYPE_NOTE) {
             mCheckBox.setVisibility(View.VISIBLE);
             mCheckBox.setChecked(checked);
@@ -57,6 +74,7 @@ public class NotesListItem extends LinearLayout {
         }
 
         mItemData = data;
+        // 处理通话记录文件夹的显示
         if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
             mCallName.setVisibility(View.GONE);
             mAlert.setVisibility(View.VISIBLE);
@@ -64,27 +82,34 @@ public class NotesListItem extends LinearLayout {
             mTitle.setText(context.getString(R.string.call_record_folder_name)
                     + context.getString(R.string.format_folder_files_count, data.getNotesCount()));
             mAlert.setImageResource(R.drawable.call_record);
-        } else if (data.getParentId() == Notes.ID_CALL_RECORD_FOLDER) {
+        }
+        // 处理通话记录便签的显示
+        else if (data.getParentId() == Notes.ID_CALL_RECORD_FOLDER) {
             mCallName.setVisibility(View.VISIBLE);
             mCallName.setText(data.getCallName());
-            mTitle.setTextAppearance(context,R.style.TextAppearanceSecondaryItem);
+            mTitle.setTextAppearance(context, R.style.TextAppearanceSecondaryItem);
             mTitle.setText(DataUtils.getFormattedSnippet(data.getSnippet()));
+            // 显示提醒图标（如果有提醒）
             if (data.hasAlert()) {
                 mAlert.setImageResource(R.drawable.clock);
                 mAlert.setVisibility(View.VISIBLE);
             } else {
                 mAlert.setVisibility(View.GONE);
             }
-        } else {
+        }
+        // 处理普通便签和文件夹的显示
+        else {
             mCallName.setVisibility(View.GONE);
             mTitle.setTextAppearance(context, R.style.TextAppearancePrimaryItem);
 
             if (data.getType() == Notes.TYPE_FOLDER) {
+                // 文件夹显示名称和子项数量
                 mTitle.setText(data.getSnippet()
                         + context.getString(R.string.format_folder_files_count,
-                                data.getNotesCount()));
+                        data.getNotesCount()));
                 mAlert.setVisibility(View.GONE);
             } else {
+                // 便签显示摘要和提醒图标（如果有）
                 mTitle.setText(DataUtils.getFormattedSnippet(data.getSnippet()));
                 if (data.hasAlert()) {
                     mAlert.setImageResource(R.drawable.clock);
@@ -94,14 +119,22 @@ public class NotesListItem extends LinearLayout {
                 }
             }
         }
+        // 显示相对时间（相对于当前时间）
         mTime.setText(DateUtils.getRelativeTimeSpanString(data.getModifiedDate()));
 
+        // 设置便签项背景
         setBackground(data);
     }
 
+    /**
+     * 设置便签项背景
+     * 根据便签类型、位置和背景颜色ID设置不同的背景
+     * @param data 便签项数据模型
+     */
     private void setBackground(NoteItemData data) {
         int id = data.getBgColorId();
         if (data.getType() == Notes.TYPE_NOTE) {
+            // 根据便签在列表中的位置设置不同背景
             if (data.isSingle() || data.isOneFollowingFolder()) {
                 setBackgroundResource(NoteItemBgResources.getNoteBgSingleRes(id));
             } else if (data.isLast()) {
@@ -112,11 +145,16 @@ public class NotesListItem extends LinearLayout {
                 setBackgroundResource(NoteItemBgResources.getNoteBgNormalRes(id));
             }
         } else {
+            // 文件夹使用统一背景
             setBackgroundResource(NoteItemBgResources.getFolderBgRes());
         }
     }
 
+    /**
+     * 获取便签项数据模型
+     * @return 便签项数据模型
+     */
     public NoteItemData getItemData() {
         return mItemData;
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/net/micode/notes/ui/NotesPreferenceActivity.java b/app/src/main/java/net/micode/notes/ui/NotesPreferenceActivity.java
index 07c5f7e..ce54a97 100644
--- a/app/src/main/java/net/micode/notes/ui/NotesPreferenceActivity.java
+++ b/app/src/main/java/net/micode/notes/ui/NotesPreferenceActivity.java
@@ -47,53 +47,60 @@ import net.micode.notes.data.Notes;
 import net.micode.notes.data.Notes.NoteColumns;
 import net.micode.notes.gtask.remote.GTaskSyncService;
 
-
+/**
+ * 便签应用偏好设置活动
+ * 提供应用设置界面，包括账户同步、背景颜色等偏好设置
+ */
 public class NotesPreferenceActivity extends PreferenceActivity {
-    public static final String PREFERENCE_NAME = "notes_preferences";
-
-    public static final String PREFERENCE_SYNC_ACCOUNT_NAME = "pref_key_account_name";
-
-    public static final String PREFERENCE_LAST_SYNC_TIME = "pref_last_sync_time";
-
-    public static final String PREFERENCE_SET_BG_COLOR_KEY = "pref_key_bg_random_appear";
-
-    private static final String PREFERENCE_SYNC_ACCOUNT_KEY = "pref_sync_account_key";
-
-    private static final String AUTHORITIES_FILTER_KEY = "authorities";
-
-    private PreferenceCategory mAccountCategory;
-
-    private GTaskReceiver mReceiver;
-
-    private Account[] mOriAccounts;
-
-    private boolean mHasAddedAccount;
-
+    // 偏好设置相关常量
+    public static final String PREFERENCE_NAME = "notes_preferences";                // 偏好设置文件名
+    public static final String PREFERENCE_SYNC_ACCOUNT_NAME = "pref_key_account_name"; // 同步账户名偏好键
+    public static final String PREFERENCE_LAST_SYNC_TIME = "pref_last_sync_time";    // 上次同步时间偏好键
+    public static final String PREFERENCE_SET_BG_COLOR_KEY = "pref_key_bg_random_appear"; // 背景颜色偏好键
+
+    private static final String PREFERENCE_SYNC_ACCOUNT_KEY = "pref_sync_account_key"; // 同步账户类别键
+    private static final String AUTHORITIES_FILTER_KEY = "authorities";               // 账户权限过滤键
+
+    private PreferenceCategory mAccountCategory;       // 账户设置类别
+    private GTaskReceiver mReceiver;                   // 同步服务广播接收器
+    private Account[] mOriAccounts;                    // 原始账户列表
+    private boolean mHasAddedAccount;                  // 是否已添加新账户标记
+
+    /**
+     * 活动创建回调
+     * @param icicle 保存的实例状态
+     */
     @Override
     protected void onCreate(Bundle icicle) {
         super.onCreate(icicle);
 
-        /* using the app icon for navigation */
+        // 设置ActionBar导航图标
         getActionBar().setDisplayHomeAsUpEnabled(true);
 
+        // 从资源加载偏好设置
         addPreferencesFromResource(R.xml.preferences);
         mAccountCategory = (PreferenceCategory) findPreference(PREFERENCE_SYNC_ACCOUNT_KEY);
+
+        // 注册同步服务广播接收器
         mReceiver = new GTaskReceiver();
         IntentFilter filter = new IntentFilter();
         filter.addAction(GTaskSyncService.GTASK_SERVICE_BROADCAST_NAME);
         registerReceiver(mReceiver, filter);
 
         mOriAccounts = null;
+        // 添加设置页面头部视图
         View header = LayoutInflater.from(this).inflate(R.layout.settings_header, null);
         getListView().addHeaderView(header, null, true);
     }
 
+    /**
+     * 活动恢复回调
+     */
     @Override
     protected void onResume() {
         super.onResume();
 
-        // need to set sync account automatically if user has added a new
-        // account
+        // 自动设置同步账户（如果添加了新账户）
         if (mHasAddedAccount) {
             Account[] accounts = getGoogleAccounts();
             if (mOriAccounts != null && accounts.length > mOriAccounts.length) {
@@ -113,17 +120,24 @@ public class NotesPreferenceActivity extends PreferenceActivity {
             }
         }
 
+        // 刷新界面
         refreshUI();
     }
 
+    /**
+     * 活动销毁回调
+     */
     @Override
     protected void onDestroy() {
         if (mReceiver != null) {
-            unregisterReceiver(mReceiver);
+            unregisterReceiver(mReceiver); // 取消注册广播接收器
         }
         super.onDestroy();
     }
 
+    /**
+     * 加载账户偏好设置
+     */
     private void loadAccountPreference() {
         mAccountCategory.removeAll();
 
@@ -135,16 +149,15 @@ public class NotesPreferenceActivity extends PreferenceActivity {
             public boolean onPreferenceClick(Preference preference) {
                 if (!GTaskSyncService.isSyncing()) {
                     if (TextUtils.isEmpty(defaultAccount)) {
-                        // the first time to set account
+                        // 首次设置账户
                         showSelectAccountAlertDialog();
                     } else {
-                        // if the account has already been set, we need to promp
-                        // user about the risk
+                        // 已设置账户，提示更换风险
                         showChangeAccountConfirmAlertDialog();
                     }
                 } else {
                     Toast.makeText(NotesPreferenceActivity.this,
-                            R.string.preferences_toast_cannot_change_account, Toast.LENGTH_SHORT)
+                                    R.string.preferences_toast_cannot_change_account, Toast.LENGTH_SHORT)
                             .show();
                 }
                 return true;
@@ -154,11 +167,14 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         mAccountCategory.addPreference(accountPref);
     }
 
+    /**
+     * 加载同步按钮
+     */
     private void loadSyncButton() {
         Button syncButton = (Button) findViewById(R.id.preference_sync_button);
         TextView lastSyncTimeView = (TextView) findViewById(R.id.prefenerece_sync_status_textview);
 
-        // set button state
+        // 设置按钮状态
         if (GTaskSyncService.isSyncing()) {
             syncButton.setText(getString(R.string.preferences_button_sync_cancel));
             syncButton.setOnClickListener(new View.OnClickListener() {
@@ -176,7 +192,7 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         }
         syncButton.setEnabled(!TextUtils.isEmpty(getSyncAccountName(this)));
 
-        // set last sync time
+        // 设置上次同步时间
         if (GTaskSyncService.isSyncing()) {
             lastSyncTimeView.setText(GTaskSyncService.getProgressString());
             lastSyncTimeView.setVisibility(View.VISIBLE);
@@ -193,14 +209,21 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         }
     }
 
+    /**
+     * 刷新用户界面
+     */
     private void refreshUI() {
         loadAccountPreference();
         loadSyncButton();
     }
 
+    /**
+     * 显示选择账户对话框
+     */
     private void showSelectAccountAlertDialog() {
         AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
 
+        // 设置对话框标题视图
         View titleView = LayoutInflater.from(this).inflate(R.layout.account_dialog_title, null);
         TextView titleTextView = (TextView) titleView.findViewById(R.id.account_dialog_title);
         titleTextView.setText(getString(R.string.preferences_dialog_select_account_title));
@@ -217,6 +240,7 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         mHasAddedAccount = false;
 
         if (accounts.length > 0) {
+            // 设置账户列表选项
             CharSequence[] items = new CharSequence[accounts.length];
             final CharSequence[] itemMapping = items;
             int checkedItem = -1;
@@ -237,6 +261,7 @@ public class NotesPreferenceActivity extends PreferenceActivity {
                     });
         }
 
+        // 添加"添加账户"视图
         View addAccountView = LayoutInflater.from(this).inflate(R.layout.add_account_text, null);
         dialogBuilder.setView(addAccountView);
 
@@ -244,9 +269,10 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         addAccountView.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
                 mHasAddedAccount = true;
+                // 跳转到添加账户设置页面
                 Intent intent = new Intent("android.settings.ADD_ACCOUNT_SETTINGS");
                 intent.putExtra(AUTHORITIES_FILTER_KEY, new String[] {
-                    "gmail-ls"
+                        "gmail-ls"
                 });
                 startActivityForResult(intent, -1);
                 dialog.dismiss();
@@ -254,9 +280,13 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         });
     }
 
+    /**
+     * 显示更换账户确认对话框
+     */
     private void showChangeAccountConfirmAlertDialog() {
         AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
 
+        // 设置对话框标题视图
         View titleView = LayoutInflater.from(this).inflate(R.layout.account_dialog_title, null);
         TextView titleTextView = (TextView) titleView.findViewById(R.id.account_dialog_title);
         titleTextView.setText(getString(R.string.preferences_dialog_change_account_title,
@@ -265,6 +295,7 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         subtitleTextView.setText(getString(R.string.preferences_dialog_change_account_warn_msg));
         dialogBuilder.setCustomTitle(titleView);
 
+        // 设置对话框选项
         CharSequence[] menuItemArray = new CharSequence[] {
                 getString(R.string.preferences_menu_change_account),
                 getString(R.string.preferences_menu_remove_account),
@@ -283,11 +314,19 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         dialogBuilder.show();
     }
 
+    /**
+     * 获取Google账户列表
+     * @return Google账户数组
+     */
     private Account[] getGoogleAccounts() {
         AccountManager accountManager = AccountManager.get(this);
         return accountManager.getAccountsByType("com.google");
     }
 
+    /**
+     * 设置同步账户
+     * @param account 账户名
+     */
     private void setSyncAccount(String account) {
         if (!getSyncAccountName(this).equals(account)) {
             SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
@@ -299,10 +338,10 @@ public class NotesPreferenceActivity extends PreferenceActivity {
             }
             editor.commit();
 
-            // clean up last sync time
+            // 清除上次同步时间
             setLastSyncTime(this, 0);
 
-            // clean up local gtask related info
+            // 清理本地GTask相关信息（在后台线程执行）
             new Thread(new Runnable() {
                 public void run() {
                     ContentValues values = new ContentValues();
@@ -318,6 +357,9 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         }
     }
 
+    /**
+     * 移除同步账户
+     */
     private void removeSyncAccount() {
         SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
         SharedPreferences.Editor editor = settings.edit();
@@ -329,7 +371,7 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         }
         editor.commit();
 
-        // clean up local gtask related info
+        // 清理本地GTask相关信息（在后台线程执行）
         new Thread(new Runnable() {
             public void run() {
                 ContentValues values = new ContentValues();
@@ -340,12 +382,22 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         }).start();
     }
 
+    /**
+     * 获取同步账户名
+     * @param context 上下文
+     * @return 同步账户名，若无则返回空字符串
+     */
     public static String getSyncAccountName(Context context) {
         SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                 Context.MODE_PRIVATE);
         return settings.getString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
     }
 
+    /**
+     * 设置上次同步时间
+     * @param context 上下文
+     * @param time 时间戳（毫秒）
+     */
     public static void setLastSyncTime(Context context, long time) {
         SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                 Context.MODE_PRIVATE);
@@ -354,29 +406,41 @@ public class NotesPreferenceActivity extends PreferenceActivity {
         editor.commit();
     }
 
+    /**
+     * 获取上次同步时间
+     * @param context 上下文
+     * @return 上次同步时间戳（毫秒），若无则返回0
+     */
     public static long getLastSyncTime(Context context) {
         SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                 Context.MODE_PRIVATE);
         return settings.getLong(PREFERENCE_LAST_SYNC_TIME, 0);
     }
 
+    /**
+     * GTask同步服务广播接收器
+     */
     private class GTaskReceiver extends BroadcastReceiver {
-
         @Override
         public void onReceive(Context context, Intent intent) {
-            refreshUI();
+            refreshUI(); // 刷新界面
             if (intent.getBooleanExtra(GTaskSyncService.GTASK_SERVICE_BROADCAST_IS_SYNCING, false)) {
                 TextView syncStatus = (TextView) findViewById(R.id.prefenerece_sync_status_textview);
                 syncStatus.setText(intent
                         .getStringExtra(GTaskSyncService.GTASK_SERVICE_BROADCAST_PROGRESS_MSG));
             }
-
         }
     }
 
+    /**
+     * 选项菜单点击处理
+     * @param item 点击的菜单项
+     * @return 是否处理该点击
+     */
     public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()) {
             case android.R.id.home:
+                // 返回便签列表活动
                 Intent intent = new Intent(this, NotesListActivity.class);
                 intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                 startActivity(intent);
@@ -385,4 +449,4 @@ public class NotesPreferenceActivity extends PreferenceActivity {
                 return false;
         }
     }
-}
+}
\ No newline at end of file