/*
 * 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.accounts.Account;
import android.accounts.AccountManager;
import android.app.ActionBar;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.ContentValues;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.Preference.OnPreferenceClickListener;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
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;


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;

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        /* using the app icon for navigation */
        getActionBar().setDisplayHomeAsUpEnabled(true);

        addPreferencesFromResource(R.xml.preferences);
        mAccountCategory = (PreferenceCategory) findPreference(PREFERENCE_SYNC_ACCOUNT_KEY);
        mReceiver = new GTaskReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(GTaskSyncService.GTASK_SERVICE_BROADCAST_NAME);
        registerReceiver(mReceiver, filter);

        mOriAccounts = null;
        View header = LayoutInflater.from(this).inflate(R.layout.settings_header, null);
        getListView().addHeaderView(header, null, true);
    }

    @Override
    protected void onResume() {
        super.onResume();

        // need to set sync account automatically if user has added a new
        // account
        if (mHasAddedAccount) {
            Account[] accounts = getGoogleAccounts();
            if (mOriAccounts != null && accounts.length > mOriAccounts.length) {
                for (Account accountNew : accounts) {
                    boolean found = false;
                    for (Account accountOld : mOriAccounts) {
                        if (TextUtils.equals(accountOld.name, accountNew.name)) {
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        setSyncAccount(accountNew.name);
                        break;
                    }
                }
            }
        }

        refreshUI();
    }

    @Override
    protected void onDestroy() {
        if (mReceiver != null) {
            unregisterReceiver(mReceiver);
        }
        super.onDestroy();
    }

    private void loadAccountPreference() {
        mAccountCategory.removeAll();

        Preference accountPref = new Preference(this);
        final String defaultAccount = getSyncAccountName(this);
        accountPref.setTitle(getString(R.string.preferences_account_title));
        accountPref.setSummary(getString(R.string.preferences_account_summary));
        accountPref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
            public boolean onPreferenceClick(Preference preference) {
                if (!GTaskSyncService.isSyncing()) {
                    if (TextUtils.isEmpty(defaultAccount)) {
                        // the first time to set account
                        showSelectAccountAlertDialog();
                    } else {
                        // if the account has already been set, we need to promp
                        // user about the risk
                        showChangeAccountConfirmAlertDialog();
                    }
                } else {
                    Toast.makeText(NotesPreferenceActivity.this,
                            R.string.preferences_toast_cannot_change_account, Toast.LENGTH_SHORT)
                            .show();
                }
                return true;
            }
        });

        mAccountCategory.addPreference(accountPref);
    }

    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
        if (GTaskSyncService.isSyncing()) {
            syncButton.setText(getString(R.string.preferences_button_sync_cancel));
            syncButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    GTaskSyncService.cancelSync(NotesPreferenceActivity.this);
                }
            });
        } else {
            syncButton.setText(getString(R.string.preferences_button_sync_immediately));
            syncButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    GTaskSyncService.startSync(NotesPreferenceActivity.this);
                }
            });
        }
        syncButton.setEnabled(!TextUtils.isEmpty(getSyncAccountName(this)));

        // set last sync time
        if (GTaskSyncService.isSyncing()) {
            lastSyncTimeView.setText(GTaskSyncService.getProgressString());
            lastSyncTimeView.setVisibility(View.VISIBLE);
        } else {
            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);
            } else {
                lastSyncTimeView.setVisibility(View.GONE);
            }
        }
    }

    private void refreshUI() {
        loadAccountPreference();
        loadSyncButton();
    }

    private void showSelectAccountAlertDialog() {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);

        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));

        dialogBuilder.setCustomTitle(titleView);
        dialogBuilder.setPositiveButton(null, null);

        Account[] accounts = getGoogleAccounts();
        String defAccount = getSyncAccountName(this);

        mOriAccounts = accounts;
        mHasAddedAccount = false;

        if (accounts.length > 0) {
            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;
                }
                items[index++] = account.name;
            }
            dialogBuilder.setSingleChoiceItems(items, checkedItem,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            setSyncAccount(itemMapping[which].toString());
                            dialog.dismiss();
                            refreshUI();
                        }
                    });
        }

        View addAccountView = LayoutInflater.from(this).inflate(R.layout.add_account_text, null);
        dialogBuilder.setView(addAccountView);

        final AlertDialog dialog = dialogBuilder.show();
        addAccountView.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                mHasAddedAccount = true;
                Intent intent = new Intent("android.settings.ADD_ACCOUNT_SETTINGS");
                intent.putExtra(AUTHORITIES_FILTER_KEY, new String[] {
                    "gmail-ls"
                });
                startActivityForResult(intent, -1);
                dialog.dismiss();
            }
        });
    }

    private void showChangeAccountConfirmAlertDialog() {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);

        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));
        dialogBuilder.setCustomTitle(titleView);

        CharSequence[] menuItemArray = new CharSequence[] {
                getString(R.string.preferences_menu_change_account),
                getString(R.string.preferences_menu_remove_account),
                getString(R.string.preferences_menu_cancel)
        };
        dialogBuilder.setItems(menuItemArray, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                if (which == 0) {
                    showSelectAccountAlertDialog();
                } else if (which == 1) {
                    removeSyncAccount();
                    refreshUI();
                }
            }
        });
        dialogBuilder.show();
    }

    private Account[] getGoogleAccounts() {
        AccountManager accountManager = AccountManager.get(this);
        return accountManager.getAccountsByType("com.google");
    }

    private void setSyncAccount(String account) {
        if (!getSyncAccountName(this).equals(account)) {
            SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = settings.edit();
            if (account != null) {
                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, account);
            } else {
                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
            }
            editor.commit();

            // clean up last sync time
            setLastSyncTime(this, 0);

            // 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();

            Toast.makeText(NotesPreferenceActivity.this,
                    getString(R.string.preferences_toast_success_set_accout, account),
                    Toast.LENGTH_SHORT).show();
        }
    }

    private void removeSyncAccount() {
        SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        if (settings.contains(PREFERENCE_SYNC_ACCOUNT_NAME)) {
            editor.remove(PREFERENCE_SYNC_ACCOUNT_NAME);
        }
        if (settings.contains(PREFERENCE_LAST_SYNC_TIME)) {
            editor.remove(PREFERENCE_LAST_SYNC_TIME);
        }
        editor.commit();

        // 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();
    }

    public static String getSyncAccountName(Context context) {
        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                Context.MODE_PRIVATE);
        return settings.getString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
    }

    public static void setLastSyncTime(Context context, long time) {
        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        editor.putLong(PREFERENCE_LAST_SYNC_TIME, time);
        editor.commit();
    }

    public static long getLastSyncTime(Context context) {
        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                Context.MODE_PRIVATE);
        return settings.getLong(PREFERENCE_LAST_SYNC_TIME, 0);
    }

    private class GTaskReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            refreshUI();
            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));
            }

        }
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                Intent intent = new Intent(this, NotesListActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(intent);
                return true;
            default:
                return false;
        }
    }
}
package net.micode.notes.ui;

import android.accounts.Account;
import android.accounts.AccountManager;
import android.app.ActionBar;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.ContentValues;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.Preference.OnPreferenceClickListener;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
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;

// NotesPreferenceActivity类继承自PreferenceActivity，是用于管理便签应用偏好设置的Activity，
// 涉及与账户相关的设置（如选择同步账户、切换账户、移除账户等）、同步操作的控制（开始同步、取消同步）以及根据不同状态更新界面显示等功能逻辑。
public class NotesPreferenceActivity extends PreferenceActivity {

    // 用于存储偏好设置名称的常量，作为获取SharedPreferences对象时的名称参数，用于保存和读取应用的各种偏好设置数据。
    public static final String PREFERENCE_NAME = "notes_preferences";
    // 用于存储同步账户名称偏好设置的键名，通过该键可以在SharedPreferences中存取当前选择的同步账户名称信息。
    public static final String PREFERENCE_SYNC_ACCOUNT_NAME = "pref_key_account_name";
    // 用于存储上次同步时间偏好设置的键名，用于记录和获取应用最后一次同步操作的时间戳信息。
    public static final String PREFERENCE_LAST_SYNC_TIME = "pref_last_sync_time";
    // 用于存储设置背景颜色相关偏好设置的键名（具体关于背景颜色随机出现的设置相关，从名称推测可能功能），此处代码中未看到详细使用逻辑，可能在应用其他涉及背景颜色设置的地方使用。
    public static final String PREFERENCE_SET_BG_COLOR_KEY = "pref_key_bg_random_appear";
    // 用于在偏好设置中标识账户相关分类的键名，用于在布局资源中找到对应的PreferenceCategory组件，方便进行账户相关偏好设置项的管理操作。
    private static final String PREFERENCE_SYNC_ACCOUNT_KEY = "pref_sync_account_key";
    // 用于在添加账户意图中传递权限过滤相关信息的键名（从代码中看是与添加谷歌账户相关操作中使用，具体过滤“gmail-ls”权限相关情况），用于控制账户添加时的一些权限筛选逻辑。
    private static final String AUTHORITIES_FILTER_KEY = "authorities";

    // 用于存储偏好设置中账户分类的PreferenceCategory对象，通过它可以对账户相关的偏好设置项进行添加、移除等操作，方便管理账户设置相关的UI展示和逻辑处理。
    private PreferenceCategory mAccountCategory;
    // 用于接收同步服务相关广播的广播接收器对象，当同步服务有状态变化（如开始同步、取消同步、同步进度更新等）时会接收到广播并进行相应的界面更新等操作。
    private GTaskReceiver mReceiver;
    // 用于存储原始的账户列表信息，在判断是否新增账户等逻辑中使用，通过对比前后账户列表来确定是否有账户添加的情况发生。
    private Account[] mOriAccounts;
    // 用于标记是否添加了新账户的布尔变量，在账户相关操作逻辑中（如在`onResume`方法中判断是否需要自动设置同步账户）根据其值来执行相应的处理逻辑。
    private boolean mHasAddedAccount;

    // Activity创建时调用的方法，进行一些初始化操作，如设置ActionBar的返回按钮可用、加载偏好设置资源文件、获取账户分类组件、注册广播接收器以及添加列表头部视图等操作。
    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        /* using the app icon for navigation */
        getActionBar().setDisplayHomeAsUpEnabled(true);

        addPreferencesFromResource(R.xml.preferences);
        mAccountCategory = (PreferenceCategory) findPreference(PREFERENCE_SYNC_ACCOUNT_KEY);
        mReceiver = new GTaskReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(GTaskSyncService.GTASK_SERVICE_BROADCAST_NAME);
        registerReceiver(mReceiver, filter);

        mOriAccounts = null;
        View header = LayoutInflater.from(this).inflate(R.layout.settings_header, null);
        getListView().addHeaderView(header, null, true);
    }

    // Activity重新恢复到前台时调用的方法，在这里主要判断是否有新添加的账户，如果有则尝试自动设置同步账户，然后调用`refreshUI`方法更新整个偏好设置界面的显示内容，以反映最新的状态。
    @Override
    protected void onResume() {
        super.onResume();

        // need to set sync account automatically if user has added a new
        // account
        if (mHasAddedAccount) {
            Account[] accounts = getGoogleAccounts();
            if (mOriAccounts!= null && accounts.length > mOriAccounts.length) {
                for (Account accountNew : accounts) {
                    boolean found = false;
                    for (Account accountOld : mOriAccounts) {
                        if (TextUtils.equals(accountOld.name, accountNew.name)) {
                            found = true;
                            break;
                        }
                    }
                    if (!found) {
                        setSyncAccount(accountNew.name);
                        break;
                    }
                }
            }
        }

        refreshUI();
    }

    // Activity销毁时调用的方法，在这里主要进行广播接收器的注销操作，避免出现内存泄漏等问题，然后调用父类的销毁方法完成其他相关的清理工作。
    @Override
    protected void onDestroy() {
        if (mReceiver!= null) {
            unregisterReceiver(mReceiver);
        }
        super.onDestroy();
    }

    // 用于加载账户偏好设置相关的UI展示内容，先移除账户分类下已有的所有偏好设置项，然后创建一个新的偏好设置项用于显示账户相关信息，并设置其标题、摘要以及点击监听器等，最后将其添加到账户分类中进行展示。
    private void loadAccountPreference() {
        mAccountCategory.removeAll();

        Preference accountPref = new Preference(this);
        final String defaultAccount = getSyncAccountName(this);
        accountPref.setTitle(getString(R.string.preferences_account_title));
        accountPref.setSummary(getString(R.string.preferences_account_summary));
        accountPref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
            public boolean onPreferenceClick(Preference preference) {
                if (!GTaskSyncService.isSyncing()) {
                    if (TextUtils.isEmpty(defaultAccount)) {
                        // the first time to set account
                        showSelectAccountAlertDialog();
                    } else {
                        // if the account has already been set, we need to promp
                        // user about the risk
                        showChangeAccountConfirmAlertDialog();
                    }
                } else {
                    Toast.makeText(NotesPreferenceActivity.this,
                            R.string.preferences_toast_cannot_change_account, Toast.LENGTH_SHORT)
                           .show();
                }
                return true;
            }
        });

        mAccountCategory.addPreference(accountPref);
    }

    // 用于加载同步按钮相关的UI展示和点击事件逻辑设置，根据同步服务当前是否正在同步来设置按钮的文本（如显示“同步”或“取消同步”）以及对应的点击监听器（启动或取消同步操作），
    // 同时根据同步情况和上次同步时间来设置显示同步状态文本视图的内容和可见性，展示给用户同步相关的状态信息。
    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
        if (GTaskSyncService.isSyncing()) {
            syncButton.setText(getString(R.string.preferences_button_sync_cancel));
            syncButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    GTaskSyncService.cancelSync(NotesPreferenceActivity.this);
                }
            });
        } else {
            syncButton.setText(getString(R.string.preferences_button_sync_immediately));
            syncButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    GTaskSyncService.startSync(NotesPreferenceActivity.this);
                }
            });
        }
        syncButton.setEnabled(!TextUtils.isEmpty(getSyncAccountName(this)));

        // set last sync time
        if (GTaskSyncService.isSyncing()) {
            lastSyncTimeView.setText(GTaskSyncService.getProgressString());
            lastSyncTimeView.setVisibility(View.VISIBLE);
        } else {
            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);
            } else {
                lastSyncTimeView.setVisibility(View.GONE);
            }
        }
    }

    // 用于更新整个偏好设置界面的显示内容，通过调用`loadAccountPreference`和`loadSyncButton`方法分别更新账户相关设置和同步按钮相关的UI展示，以反映最新的应用状态和设置信息。
    private void refreshUI() {
        loadAccountPreference();
        loadSyncButton();
    }

    // 用于显示选择账户的提醒对话框，在首次设置同步账户或者需要重新选择账户时弹出，对话框中展示可选的谷歌账户列表供用户选择，
    // 同时提供添加新账户的入口，用户选择账户后会设置相应的同步账户并更新界面显示，选择添加新账户则跳转到系统的添加账户设置页面。
    private void showSelectAccountAlertDialog() {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);

        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));

        dialogBuilder.setCustomTitle(titleView);
        dialogBuilder.setPositiveButton(null, null);

        Account[] accounts = getGoogleAccounts();
        String defAccount = getSyncAccountName(this);

        mOriAccounts = accounts;
        mHasAddedAccount = false;

        if (accounts.length > 0) {
            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;
                }
                items[index++] = account.name;
            }
            dialogBuilder.setSingleChoiceItems(items, checkedItem,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            setSyncAccount(itemMapping[which].toString());
                            dialog.dismiss();
                            refreshUI();
                        }
                    });
        }

        View addAccountView = LayoutInflater.from(this).inflate(R.layout.add_account_text, null);
        dialogBuilder.setView(addAccountView);

        final AlertDialog dialog = dialogBuilder.show();
        addAccountView.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                mHasAddedAccount = true;
                Intent intent = new Intent("android.settings.ADD_ACCOUNT_SETTINGS");
                intent.putExtra(AUTHORITIES_FILTER_KEY, new String[] {
                    "gmail-ls"
                });
                startActivityForResult(intent, -1);
                dialog.dismiss();
            }
        });
    }

    // 用于显示确认更改账户的提醒对话框，当已经设置了同步账户后再次点击账户设置项时弹出，对话框中提示用户更改账户的风险，并提供更改账户、移除账户和取消操作的选项，
    // 用户选择相应操作后会执行对应的逻辑（如重新选择账户、移除账户并更新界面等）。
    private void showChangeAccountConfirmAlertDialog() {
        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);

        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));
        dialogBuilder.setCustomTitle(titleView);

        CharSequence[] menuItemArray = new CharSequence[] {
                getString(R.string.preferences_menu_change_account),
                getString(R.string.preferences_menu_remove_account),
                getString(R.string.preferences_menu_cancel)
        };
        dialogBuilder.setItems(menuItemArray, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                if (which == 0) {
                    showSelectAccountAlertDialog();
                } else if (which == 1) {
                    removeSyncAccount();
                    refreshUI();
                }
            }
        });
        dialogBuilder.show();
    }

    // 用于获取设备上已登录的谷歌账户列表，通过`AccountManager`获取指定类型（“com.google”）的账户信息，返回账户数组，方便在账户选择等相关操作中展示和使用这些账户数据。
    private Account[] getGoogleAccounts() {
        AccountManager accountManager = AccountManager.get(this);
        return accountManager.getAccountsByType("com.google");
    }

    // 用于设置同步账户名称，将传入的账户名称保存到SharedPreferences中，同时进行一些相关的清理操作，如重置上次同步时间、清除本地与同步任务（`gtask`）相关的信息等，
    // 最后通过Toast提示用户设置成功的信息，并且只有当传入的账户名称与当前保存的不一致时才执行实际的设置操作。
    private void setSyncAccount(String account) {
        if (!getSyncAccountName(this).equals(account)) {
            SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = settings.edit();
            if (account!= null) {
                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, account);
            } else {
                editor.putString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
            }
            editor.commit();

            // clean up last sync time
            setLastSyncTime(this, 0);

            // 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();

            Toast.makeText(NotesPreferenceActivity.this,
                    getString(R.string.preferences_toast_success_set_accout, account),
                    Toast.LENGTH_SHORT).show();
        }
    }

    // 用于移除当前设置的同步账户相关信息，从SharedPreferences中移除同步账户名称和上次同步时间的记录，同时清除本地与同步任务（`gtask`）相关的信息，以达到彻底移除账户相关设置的效果。
    private void removeSyncAccount() {
        SharedPreferences settings = getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        if (settings.contains(PREFERENCE_SYNC_ACCOUNT_NAME)) {
            editor.remove(PREFERENCE_SYNC_ACCOUNT_NAME);
        }
        if (settings.contains(PREFERENCE_LAST_SYNC_TIME)) {
            editor.remove(PREFERENCE_LAST_SYNC_TIME);
        }
        editor.commit();

        // 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();
    }

    // 静态方法，用于获取当前设置的同步账户名称，从SharedPreferences中根据对应的键（`PREFERENCE_SYNC_ACCOUNT_NAME`）读取账户名称信息，如果不存在则返回空字符串。
    public static String getSyncAccountName(Context context) {
        SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME,
                Context.MODE_PRIVATE);
        return settings.getString(PREFERENCE_SYNC_ACCOUNT_NAME, "");
    }

    // 静态方法，用于设置上次同步时间，将传入的时间戳保存到SharedPreferences中，通过编辑对象提交更改，方便后续在界面展示等地方获取并显示上次同步的时间信息。
    public static void setLastSyncTime(Context context, long time) {
        SharedPreferences settings = context