diff --git a/doc/NotesPreferenceActivity .txt b/doc/NotesPreferenceActivity .txt
new file mode 100644
index 0000000..e3d03fa
--- /dev/null
+++ b/doc/NotesPreferenceActivity .txt	
@@ -0,0 +1,476 @@
+public class NotesPreferenceActivity extends PreferenceActivity {
+    public static final String PREFERENCE_NAME = "notes_preferences";
+                              //优先名 
+    public static final String PREFERENCE_SYNC_ACCOUNT_NAME = "pref_key_account_name";
+                              //同步账号
+    public static final String PREFERENCE_LAST_SYNC_TIME = "pref_last_sync_time";
+                               //同步时间
+    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";
+                               //同步密码
+    private static final String AUTHORITIES_FILTER_KEY = "authorities";
+                               //本地密码
+    private PreferenceCategory mAccountCategory;
+                                 //账户分组
+    private GTaskReceiver mReceiver;
+                              //同步任务接收器
+    private Account[] mOriAccounts;
+                              //账户
+    private boolean mHasAddedAccount;
+                             //账户的hash标记
+ 
+    @Override
+    /*
+     *函数功能：创建一个activity，在函数里要完成所有的正常静态设置
+     *参数：Bundle icicle：存放了 activity 当前的状态
+     *函数实现：如下注释
+     */
+    protected void onCreate(Bundle icicle) {
+    	//先执行父类的创建函数
+        super.onCreate(icicle);
+        
+        /* using the app icon for navigation */
+        getActionBar().setDisplayHomeAsUpEnabled(true);
+        //给左上角图标的左边加上一个返回的图标 
+ 
+        addPreferencesFromResource(R.xml.preferences);
+        //添加xml来源并显示 xml
+        mAccountCategory = (PreferenceCategory) findPreference(PREFERENCE_SYNC_ACCOUNT_KEY);
+        //根据同步账户关键码来初始化分组
+        mReceiver = new GTaskReceiver();
+        IntentFilter filter = new IntentFilter();
+        filter.addAction(GTaskSyncService.GTASK_SERVICE_BROADCAST_NAME);
+        registerReceiver(mReceiver, filter);
+        //初始化同步组件
+ 
+        mOriAccounts = null;
+        View header = LayoutInflater.from(this).inflate(R.layout.settings_header, null);
+        //获取listvivew，ListView的作用:用于列出所有选择 
+        getListView().addHeaderView(header, null, true);
+        //在listview组件上方添加其他组件
+    }
+ 
+    @Override
+    /*
+     * 函数功能：activity交互功能的实现，用于接受用户的输入
+     * 函数实现：如下注释
+     */
+    protected void onResume() {
+    	//先执行父类 的交互实现
+        super.onResume();
+ 
+        // need to set sync account automatically if user has added a new
+        // account
+        if (mHasAddedAccount) {
+        	//若用户新加了账户则自动设置同步账户
+            Account[] accounts = getGoogleAccounts();
+            //获取google同步账户
+            if (mOriAccounts != null && accounts.length > mOriAccounts.length) {
+                //若原账户不为空且当前账户有增加
+            	for (Account accountNew : accounts) {
+                    boolean found = false;
+                    for (Account accountOld : mOriAccounts) {
+                        if (TextUtils.equals(accountOld.name, accountNew.name)) {
+                        	//更新账户
+                            found = true;
+                            break;
+                        }
+                    }
+                    if (!found) {
+                        setSyncAccount(accountNew.name);
+                        //若是没有找到旧的账户，那么同步账号中就只添加新账户
+                        break;
+                    }
+                }
+            }
+        }
+ 
+        refreshUI();
+        //刷新标签界面
+    }
+ 
+    @Override
+    /*
+     * 函数功能：销毁一个activity
+     * 函数实现：如下注释
+     */
+    protected void onDestroy() {
+        if (mReceiver != null) {
+            unregisterReceiver(mReceiver);
+            //注销接收器
+        }
+        super.onDestroy();
+        //执行父类的销毁动作
+    }
+ 
+    /*
+     * 函数功能：重新设置账户信息
+     * 函数实现：如下注释
+     */
+    private void loadAccountPreference() {
+        mAccountCategory.removeAll();
+        //销毁所有的分组
+        Preference accountPref = new Preference(this);
+        //建立首选项
+        final String defaultAccount = getSyncAccountName(this);
+        accountPref.setTitle(getString(R.string.preferences_account_title));
+        accountPref.setSummary(getString(R.string.preferences_account_summary));
+        //设置首选项的大标题和小标题
+        accountPref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
+            public boolean onPreferenceClick(Preference preference) {
+            	//建立监听器
+                if (!GTaskSyncService.isSyncing()) {
+                    if (TextUtils.isEmpty(defaultAccount)) {
+                        // the first time to set account
+                    	//若是第一次建立账户显示选择账户提示对话框
+                        showSelectAccountAlertDialog();
+                    } else {
+                        // if the account has already been set, we need to promp
+                        // user about the risk
+                    	//若是已经建立则显示修改对话框并进行修改操作
+                        showChangeAccountConfirmAlertDialog();
+                    }
+                } else {
+                	//若在没有同步的情况下，则在toast中显示不能修改
+                    Toast.makeText(NotesPreferenceActivity.this,
+                            R.string.preferences_toast_cannot_change_account, Toast.LENGTH_SHORT)
+                            .show();
+                }
+                return true;
+            }
+        });
+ 
+        //根据新建首选项编辑新的账户分组
+        mAccountCategory.addPreference(accountPref);
+    }
+ 
+    /*
+     *函数功能：设置按键的状态和最后同步的时间
+     *函数实现：如下注释 
+     */
+    private void loadSyncButton() {
+        Button syncButton = (Button) findViewById(R.id.preference_sync_button);
+        TextView lastSyncTimeView = (TextView) findViewById(R.id.prefenerece_sync_status_textview);
+        //获取同步按钮控件和最终同步时间的的窗口
+        // set button state
+        //设置按钮的状态
+        if (GTaskSyncService.isSyncing()) {
+        	//若是在同步状态下
+            syncButton.setText(getString(R.string.preferences_button_sync_cancel));
+            syncButton.setOnClickListener(new View.OnClickListener() {
+                public void onClick(View v) {
+                    GTaskSyncService.cancelSync(NotesPreferenceActivity.this);
+                }
+            });
+            //设置按钮显示的文本为“取消同步”以及监听器
+        } else {
+            syncButton.setText(getString(R.string.preferences_button_sync_immediately));
+            syncButton.setOnClickListener(new View.OnClickListener() {
+                public void onClick(View v) {
+                    GTaskSyncService.startSync(NotesPreferenceActivity.this);
+                }
+            });
+          //若是不同步则设置按钮显示的文本为“立即同步”以及对应监听器
+        }
+        syncButton.setEnabled(!TextUtils.isEmpty(getSyncAccountName(this)));
+        //设置按键可用还是不可用
+ 
+        // set last sync time
+        // 设置最终同步时间
+        if (GTaskSyncService.isSyncing()) {
+        	//若是在同步的情况下
+            lastSyncTimeView.setText(GTaskSyncService.getProgressString());
+            lastSyncTimeView.setVisibility(View.VISIBLE);
+            // 根据当前同步服务器设置时间显示框的文本以及可见性
+        } else {
+        	//若是非同步情况
+            long lastSyncTime = getLastSyncTime(this);
+            if (lastSyncTime != 0) {
+                lastSyncTimeView.setText(getString(R.string.preferences_last_sync_time,
+                        DateFormat.format(getString(R.string.preferences_last_sync_time_format),
+                                lastSyncTime)));
+                lastSyncTimeView.setVisibility(View.VISIBLE);
+                //则根据最后同步时间的信息来编辑时间显示框的文本内容和可见性
+            } else {
+            	 //若时间为空直接设置为不可见状态
+                lastSyncTimeView.setVisibility(View.GONE);
+            }
+        }
+    }
+     /*
+      *函数功能：刷新标签界面
+      *函数实现：调用上文设置账号和设置按键两个函数来实现 
+      */
+    private void refreshUI() {
+        loadAccountPreference();
+        loadSyncButton();
+    }
+ 
+    /*
+     * 函数功能：显示账户选择的对话框并进行账户的设置
+     * 函数实现：如下注释
+     */
+    private void showSelectAccountAlertDialog() {
+        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
+        //创建一个新的对话框
+ 
+        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));
+        TextView subtitleTextView = (TextView) titleView.findViewById(R.id.account_dialog_subtitle);
+        subtitleTextView.setText(getString(R.string.preferences_dialog_select_account_tips));
+        //设置标题以及子标题的内容
+        dialogBuilder.setCustomTitle(titleView);
+        dialogBuilder.setPositiveButton(null, null);
+        //设置对话框的自定义标题，建立一个YES的按钮
+        Account[] accounts = getGoogleAccounts();
+        String defAccount = getSyncAccountName(this);
+        //获取同步账户信息
+        mOriAccounts = accounts;
+        mHasAddedAccount = false;
+ 
+        if (accounts.length > 0) {
+        	//若账户不为空
+            CharSequence[] items = new CharSequence[accounts.length];
+            final CharSequence[] itemMapping = items;
+            int checkedItem = -1;
+            int index = 0;
+            for (Account account : accounts) {
+                if (TextUtils.equals(account.name, defAccount)) {
+                    checkedItem = index;
+                    //在账户列表中查询到所需账户
+                }
+                items[index++] = account.name;
+            }
+            dialogBuilder.setSingleChoiceItems(items, checkedItem,
+            		//在对话框建立一个单选的复选框
+                    new DialogInterface.OnClickListener() {
+                        public void onClick(DialogInterface dialog, int which) {
+                            setSyncAccount(itemMapping[which].toString());
+                            dialog.dismiss();
+                            //取消对话框
+                            refreshUI();
+                        }
+                        //设置点击后执行的事件，包括检录新同步账户和刷新标签界面
+                    });
+            //建立对话框网络版的监听器
+        }
+ 
+        View addAccountView = LayoutInflater.from(this).inflate(R.layout.add_account_text, null);
+        dialogBuilder.setView(addAccountView);
+        //给新加账户对话框设置自定义样式
+ 
+        final AlertDialog dialog = dialogBuilder.show();
+        //显示对话框
+        addAccountView.setOnClickListener(new View.OnClickListener() {
+            public void onClick(View v) {
+                mHasAddedAccount = true;
+                //将新加账户的hash置true
+                Intent intent = new Intent("android.settings.ADD_ACCOUNT_SETTINGS");
+                //建立网络建立组件
+                intent.putExtra(AUTHORITIES_FILTER_KEY, new String[] {
+                    "gmail-ls"
+                });
+                startActivityForResult(intent, -1);
+                //跳回上一个选项
+                dialog.dismiss();
+            }
+        });
+        //建立新加账户对话框的监听器
+    }
+ 
+    /*
+     * 函数功能：显示账户选择对话框和相关账户操作
+     * 函数实现：如下注释
+     */
+    private void showChangeAccountConfirmAlertDialog() {
+        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
+        //创建一个新的对话框
+        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,
+                getSyncAccountName(this)));
+        TextView subtitleTextView = (TextView) titleView.findViewById(R.id.account_dialog_subtitle);
+        subtitleTextView.setText(getString(R.string.preferences_dialog_change_account_warn_msg));
+        //根据同步修改的账户信息设置标题以及子标题的内容
+        dialogBuilder.setCustomTitle(titleView);
+      //设置对话框的自定义标题
+        CharSequence[] menuItemArray = new CharSequence[] {
+                getString(R.string.preferences_menu_change_account),
+                getString(R.string.preferences_menu_remove_account),
+                getString(R.string.preferences_menu_cancel)
+        };
+        //定义一些标记字符串
+        dialogBuilder.setItems(menuItemArray, new DialogInterface.OnClickListener() {
+        	//设置对话框要显示的一个list，用于显示几个命令时,即change，remove，cancel
+            public void onClick(DialogInterface dialog, int which) {
+            	//按键功能，由which来决定
+                if (which == 0) {
+                	//进入账户选择对话框
+                    showSelectAccountAlertDialog();
+                } else if (which == 1) {
+                	//删除账户并且跟新便签界面
+                    removeSyncAccount();
+                    refreshUI();
+                }
+            }
+        });
+        dialogBuilder.show();
+        //显示对话框
+    }
+ 
+    /*
+     *函数功能：获取谷歌账户
+     *函数实现：通过账户管理器直接获取
+     */
+    private Account[] getGoogleAccounts() {
+        AccountManager accountManager = AccountManager.get(this);
+        return accountManager.getAccountsByType("com.google");
+    }
+ 
+    /*
+     * 函数功能：设置同步账户
+     * 函数实现：如下注释：
+     */
+    private void setSyncAccount(String account) {
+        if (!getSyncAccountName(this).equals(account)) {
+        	//假如该账号不在同步账号列表中
+            SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
+            SharedPreferences.Editor editor = settings.edit();
+            //编辑共享的首选项
+            if (account != null) {
+                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, account);
+            } else {
+                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
+            }
+            //将该账号加入到首选项中
+            
+            editor.commit();
+            //提交修改的数据
+ 
+            
+            setLastSyncTime(this, 0);
+          //将最后同步时间清零
+ 
+            // clean up local gtask related info
+            new Thread(new Runnable() {
+                public void run() {
+                    ContentValues values = new ContentValues();
+                    values.put(NoteColumns.GTASK_ID, "");
+                    values.put(NoteColumns.SYNC_ID, 0);
+                    getContentResolver().update(Notes.CONTENT_NOTE_URI, values, null, null);
+                }
+            }).start();
+            //重置当地同步任务的信息
+ 
+            Toast.makeText(NotesPreferenceActivity.this,
+                    getString(R.string.preferences_toast_success_set_accout, account),
+                    Toast.LENGTH_SHORT).show();
+            //将toast的文本信息置为“设置账户成功”并显示出来
+        }
+    }
+    /*
+     * 函数功能：删除同步账户
+     * 函数实现：如下注释：
+     */
+    private void removeSyncAccount() {
+        SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = settings.edit();
+        //设置共享首选项
+        
+        if (settings.contains(PREFERENCE_SYNC_ACCOUNT_NAME)) {
+            editor.remove(PREFERENCE_SYNC_ACCOUNT_NAME);
+            //假如当前首选项中有账户就删除
+        }
+        if (settings.contains(PREFERENCE_LAST_SYNC_TIME)) {
+            editor.remove(PREFERENCE_LAST_SYNC_TIME);
+            //删除当前首选项中有账户时间
+        }
+        editor.commit();
+        //提交更新后的数据
+        
+        // clean up local gtask related info
+        new Thread(new Runnable() {
+            public void run() {
+                ContentValues values = new ContentValues();
+                values.put(NoteColumns.GTASK_ID, "");
+                values.put(NoteColumns.SYNC_ID, 0);
+                getContentResolver().update(Notes.CONTENT_NOTE_URI, values, null, null);
+            }
+        }).start();
+      //重置当地同步任务的信息
+    }
+    
+    /*
+     * 函数功能：获取同步账户名称
+     * 函数实现：通过共享的首选项里的信息直接获取
+     */
+    public static String getSyncAccountName(Context context) {
+        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
+                Context.MODE_PRIVATE);
+        return settings.getString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
+    }
+ 
+    /*
+     * 函数功能：设置最终同步的时间
+     * 函数实现：如下注释
+     */
+    public static void setLastSyncTime(Context context, long time) {
+        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
+                Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = settings.edit();
+        // 从共享首选项中找到相关账户并获取其编辑器
+        editor.putLong(PREFERENCE_LAST_SYNC_TIME, time);
+        editor.commit();
+        //编辑最终同步时间并提交更新
+    }
+    /*
+     * 函数功能：获取最终同步时间
+     * 函数实现：通过共享的首选项里的信息直接获取
+     */
+    public static long getLastSyncTime(Context context) {
+        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
+                Context.MODE_PRIVATE);
+        return settings.getLong(PREFERENCE_LAST_SYNC_TIME, 0);
+    }
+ 
+    /*
+     * 函数功能：接受同步信息
+     * 函数实现：继承BroadcastReceiver
+     */
+    private class GTaskReceiver extends BroadcastReceiver {
+ 
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            refreshUI();
+            if (intent.getBooleanExtra(GTaskSyncService.GTASK_SERVICE_BROADCAST_IS_SYNCING, false)) {
+                //获取随广播而来的Intent中的同步服务的数据
+            	TextView syncStatus = (TextView) findViewById(R.id.prefenerece_sync_status_textview);
+                syncStatus.setText(intent
+                        .getStringExtra(GTaskSyncService.GTASK_SERVICE_BROADCAST_PROGRESS_MSG));
+                //通过获取的数据在设置系统的状态
+            }
+ 
+        }
+    }
+ 
+    /*
+     * 函数功能：处理菜单的选项
+     * 函数实现：如下注释
+     * 参数:MenuItem菜单选项
+     */
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+        //根据选项的id选择，这里只有一个主页
+            case android.R.id.home:
+                Intent intent = new Intent(this, NotesListActivity.class);
+                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
+                startActivity(intent);
+                return true;
+                //在主页情况下在创建连接组件intent，发出清空的信号并开始一个相应的activity
+            default:
+                return false;
+        }
+    }
+}
\ No newline at end of file