MIUInote/NotesListActivity.java

/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.micode.notes.ui;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.appwidget.AppWidgetManager;
import android.content.AsyncQueryHandler;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.os.AsyncTask;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.text.Editable;
import android.text.TextUtils;
import android.text.TextWatcher;
import android.util.Log;
import android.view.ActionMode;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Display;
import android.view.HapticFeedbackConstants;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnCreateContextMenuListener;
import android.view.View.OnTouchListener;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.PopupMenu;
import android.widget.TextView;
import android.widget.Toast;

import net.micode.notes.R;
import net.micode.notes.data.Notes;
import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.gtask.remote.GTaskSyncService;
import net.micode.notes.model.WorkingNote;
import net.micode.notes.tool.BackupUtils;
import net.micode.notes.tool.DataUtils;
import net.micode.notes.tool.ResourceParser;
import net.micode.notes.ui.NotesListAdapter.AppWidgetAttribute;
import net.micode.notes.widget.NoteWidgetProvider_2x;
import net.micode.notes.widget.NoteWidgetProvider_4x;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashSet;
//NoteListActivity类，主要实现小米便签刚进入界面。该类为一种main Activity，（xml中有定义）覆盖点击事件监听及长按事件监听类。。
public class NotesListActivity extends Activity implements OnClickListener, OnItemLongClickListener {
    private static final int FOLDER_NOTE_LIST_QUERY_TOKEN = 0;

    private static final int FOLDER_LIST_QUERY_TOKEN      = 1;

    private static final int MENU_FOLDER_DELETE = 0;

    private static final int MENU_FOLDER_VIEW = 1;

    private static final int MENU_FOLDER_CHANGE_NAME = 2;

    private static final String PREFERENCE_ADD_INTRODUCTION = "net.micode.notes.introduction";

    private enum ListEditState {
        NOTE_LIST, SUB_FOLDER, CALL_RECORD_FOLDER
    };

    private ListEditState mState;

    private BackgroundQueryHandler mBackgroundQueryHandler;

    private NotesListAdapter mNotesListAdapter;

    private ListView mNotesListView;

    private Button mAddNewNote;

    private boolean mDispatch;

    private int mOriginY;

    private int mDispatchY;

    private TextView mTitleBar;

    private long mCurrentFolderId;

    private ContentResolver mContentResolver;

    private ModeCallback mModeCallBack;

    private static final String TAG = "NotesListActivity";

    public static final int NOTES_LISTVIEW_SCROLL_RATE = 30;

    private NoteItemData mFocusNoteDataItem;

    private static final String NORMAL_SELECTION = NoteColumns.PARENT_ID + "=?";

    private static final String ROOT_FOLDER_SELECTION = "(" + NoteColumns.TYPE + "<>"
            + Notes.TYPE_SYSTEM + " AND " + NoteColumns.PARENT_ID + "=?)" + " OR ("
            + NoteColumns.ID + "=" + Notes.ID_CALL_RECORD_FOLDER + " AND "
            + NoteColumns.NOTES_COUNT + ">0)";

    private final static int REQUEST_CODE_OPEN_NODE = 102;
    private final static int REQUEST_CODE_NEW_NODE  = 103;

    //创建Activity，启动其生命周期。完成设置界面样式、初始化资源、且在用户第一次使用App时进行介绍
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.note_list);
        initResources();

        /**
         * Insert an introduction when user firstly use this application
         */
        setAppInfoFromRawRes();
    }

    //intent返回数据接收函数。形参为请求码、结果码、其他intent返回的数据。主要与NoteEditActivity交互
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK
                && (requestCode == REQUEST_CODE_OPEN_NODE || requestCode == REQUEST_CODE_NEW_NODE)) {
            mNotesListAdapter.changeCursor(null);
        } else {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }

    //第一次使用App时调用，显示introduction。
    private void setAppInfoFromRawRes() {
        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
        if (!sp.getBoolean(PREFERENCE_ADD_INTRODUCTION, false)) {
            StringBuilder sb = new StringBuilder();
            InputStream in = null;
            try {
                 in = getResources().openRawResource(R.raw.introduction);
                if (in != null) {
                    InputStreamReader isr = new InputStreamReader(in);
                    BufferedReader br = new BufferedReader(isr);
                    char [] buf = new char[1024];
                    int len = 0;
                    while ((len = br.read(buf)) > 0) {
                        sb.append(buf, 0, len);
                    }
                } else {
                    Log.e(TAG, "Read introduction file error");
                    return;
                }
            } catch (IOException e) {
                e.printStackTrace();
                return;
            } finally {
                if(in != null) {
                    try {
                        in.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }

            WorkingNote note = WorkingNote.createEmptyNote(this, Notes.ID_ROOT_FOLDER,
                    AppWidgetManager.INVALID_APPWIDGET_ID, Notes.TYPE_WIDGET_INVALIDE,
                    ResourceParser.RED);
            note.setWorkingText(sb.toString());
            if (note.saveNote()) {
                sp.edit().putBoolean(PREFERENCE_ADD_INTRODUCTION, true).commit();
            } else {
                Log.e(TAG, "Save introduction note error");
                return;
            }
        }
    }
    //onCreate调用后回调，此Activity对用户可见。
    @Override
    protected void onStart() {
        super.onStart();
        startAsyncNotesListQuery();
    }

    //初始化资源
    private void initResources() {
        mContentResolver = this.getContentResolver();
        mBackgroundQueryHandler = new BackgroundQueryHandler(this.getContentResolver());
        mCurrentFolderId = Notes.ID_ROOT_FOLDER;
        mNotesListView = (ListView) findViewById(R.id.notes_list);
        mNotesListView.addFooterView(LayoutInflater.from(this).inflate(R.layout.note_list_footer, null),
                null, false);
        mNotesListView.setOnItemClickListener(new OnListItemClickListener());
        mNotesListView.setOnItemLongClickListener(this);
        mNotesListAdapter = new NotesListAdapter(this);
        mNotesListView.setAdapter(mNotesListAdapter);
        mAddNewNote = (Button) findViewById(R.id.btn_new_note);
        mAddNewNote.setOnClickListener(this);
        mAddNewNote.setOnTouchListener(new NewNoteOnTouchListener());
        mDispatch = false;
        mDispatchY = 0;
        mOriginY = 0;
        mTitleBar = (TextView) findViewById(R.id.tv_title_bar);
        mState = ListEditState.NOTE_LIST;
        mModeCallBack = new ModeCallback();
    }

    //ModeCallBack类定义了ActionMode的使用。便签长按事件通过ActionMode执行。
    //便签长按后出现选择（多个）便签删除的菜单栏，其在ActionBar中显示。
    private class ModeCallback implements ListView.MultiChoiceModeListener, OnMenuItemClickListener {
        private DropdownMenu mDropDownMenu;
        private ActionMode mActionMode;
        private MenuItem mMoveMenu;

        //ActionMode创建函数，形参为创建的ActionMode及需要通过该ActionMode显示的Menu对象
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            getMenuInflater().inflate(R.menu.note_list_options, menu);
            menu.findItem(R.id.delete).setOnMenuItemClickListener(this);
            mMoveMenu = menu.findItem(R.id.move);
            if (mFocusNoteDataItem.getParentId() == Notes.ID_CALL_RECORD_FOLDER
                    || DataUtils.getUserFolderCount(mContentResolver) == 0) {
                mMoveMenu.setVisible(false);
            } else {
                mMoveMenu.setVisible(true);
                mMoveMenu.setOnMenuItemClickListener(this);
            }
            mActionMode = mode;
            mNotesListAdapter.setChoiceMode(true);
            mNotesListView.setLongClickable(false);
            mAddNewNote.setVisibility(View.GONE);

            View customView = LayoutInflater.from(NotesListActivity.this).inflate(
                    R.layout.note_list_dropdown_menu, null);
            mode.setCustomView(customView);
            mDropDownMenu = new DropdownMenu(NotesListActivity.this,
                    (Button) customView.findViewById(R.id.selection_menu),
                    R.menu.note_list_dropdown);
            mDropDownMenu.setOnDropdownMenuItemClickListener(new PopupMenu.OnMenuItemClickListener(){
                public boolean onMenuItemClick(MenuItem item) {
                    mNotesListAdapter.selectAll(!mNotesListAdapter.isAllSelected());
                    updateMenu();
                    return true;
                }

            });
            return true;
        }

        //用于进行多选（全选）时菜单栏界面的更新
        private void updateMenu() {
            int selectedCount = mNotesListAdapter.getSelectedCount();
            // Update dropdown menu
            String format = getResources().getString(R.string.menu_select_title, selectedCount);
            mDropDownMenu.setTitle(format);
            MenuItem item = mDropDownMenu.findItem(R.id.action_select_all);
            if (item != null) {
                if (mNotesListAdapter.isAllSelected()) {
                    item.setChecked(true);
                    item.setTitle(R.string.menu_deselect_all);
                } else {
                    item.setChecked(false);
                    item.setTitle(R.string.menu_select_all);
                }
            }
        }


        //重新刷新菜单栏时调用
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            // TODO Auto-generated method stub
            return false;
        }

        //菜单栏点击动作按钮时调用、形参为ActionMode与点击的菜单项
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            // TODO Auto-generated method stub
            return false;
        }

        //销毁或退出ActionMode时调用。
        public void onDestroyActionMode(ActionMode mode) {
            mNotesListAdapter.setChoiceMode(false);
            mNotesListView.setLongClickable(true);
            mAddNewNote.setVisibility(View.VISIBLE);
        }

        //结束ActionMode时调用
        public void finishActionMode() {
            mActionMode.finish();
        }

        //检查当前菜单选择情况（针对多选）并进行菜单更新。
        public void onItemCheckedStateChanged(ActionMode mode, int position, long id,
                boolean checked) {
            mNotesListAdapter.setCheckedItem(position, checked);
            updateMenu();
        }

        //菜单项点击时调用。
        public boolean onMenuItemClick(MenuItem item) {
            if (mNotesListAdapter.getSelectedCount() == 0) {
                Toast.makeText(NotesListActivity.this, getString(R.string.menu_select_none),
                        Toast.LENGTH_SHORT).show();
                return true;
            }

            int itemId = item.getItemId();
            if (itemId == R.id.delete) {
                AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
                builder.setTitle(getString(R.string.alert_title_delete));
                builder.setIcon(android.R.drawable.ic_dialog_alert);
                builder.setMessage(getString(R.string.alert_message_delete_notes,
                        mNotesListAdapter.getSelectedCount()));
                builder.setPositiveButton(android.R.string.ok,
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog,
                                                int which) {
                                batchDelete();//批处理删除
                            }
                        });
                builder.setNegativeButton(android.R.string.cancel, null);
                builder.show();
            } else if (itemId == R.id.move) {
                startQueryDestinationFolders();
            } else {
                return false;
            }
            return true;
        }
    }

    //新便签触摸事件监听类。根据触摸事件（比如手在屏幕滑动）修正视图的位置参数
    private class NewNoteOnTouchListener implements OnTouchListener {

        public boolean onTouch(View v, MotionEvent event) {
            int action = event.getAction();
            if (action == MotionEvent.ACTION_DOWN) {
                Display display = getWindowManager().getDefaultDisplay();
                int screenHeight = display.getHeight();
                int newNoteViewHeight = mAddNewNote.getHeight();
                int start = screenHeight - newNoteViewHeight;
                int eventY = start + (int) event.getY();
                /**
                 * Minus TitleBar's height
                 */
                if (mState == ListEditState.SUB_FOLDER) {
                    eventY -= mTitleBar.getHeight();
                    start -= mTitleBar.getHeight();
                }
                /**
                 * HACKME:When click the transparent part of "New Note" button, dispatch
                 * the event to the list view behind this button. The transparent part of
                 * "New Note" button could be expressed by formula y=-0.12x+94（Unit:pixel）
                 * and the line top of the button. The coordinate based on left of the "New
                 * Note" button. The 94 represents maximum height of the transparent part.
                 * Notice that, if the background of the button changes, the formula should
                 * also change. This is very bad, just for the UI designer's strong requirement.
                 */
                if (event.getY() < (event.getX() * (-0.12) + 94)) {
                    View view = mNotesListView.getChildAt(mNotesListView.getChildCount() - 1
                            - mNotesListView.getFooterViewsCount());
                    if (view != null && view.getBottom() > start
                            && (view.getTop() < (start + 94))) {
                        mOriginY = (int) event.getY();
                        mDispatchY = eventY;
                        event.setLocation(event.getX(), mDispatchY);
                        mDispatch = true;
                        return mNotesListView.dispatchTouchEvent(event);
                    }
                }
            } else if (action == MotionEvent.ACTION_MOVE) {
                if (mDispatch) {
                    mDispatchY += (int) event.getY() - mOriginY;
                    event.setLocation(event.getX(), mDispatchY);
                    return mNotesListView.dispatchTouchEvent(event);
                }
            } else {
                if (mDispatch) {
                    event.setLocation(event.getX(), mDispatchY);
                    mDispatch = false;
                    return mNotesListView.dispatchTouchEvent(event);
                }
            }
            return false;
        }

    };

    //已同步便签查询。当进入一个新文件夹时会向数据库发送查询当前文件夹下的便签请求。返回查询结果。这是一个异步查询进程。

    private void startAsyncNotesListQuery() {
        String selection = (mCurrentFolderId == Notes.ID_ROOT_FOLDER) ? ROOT_FOLDER_SELECTION
                : NORMAL_SELECTION;
        mBackgroundQueryHandler.startQuery(FOLDER_NOTE_LIST_QUERY_TOKEN, null,
                Notes.CONTENT_NOTE_URI, NoteItemData.PROJECTION, selection, new String[] {
                    String.valueOf(mCurrentFolderId)
                }, NoteColumns.TYPE + " DESC," + NoteColumns.MODIFIED_DATE + " DESC");
    }

    //背景查询消息处理类。主要功能是将查询后得到的便签在界面显示

    private final class BackgroundQueryHandler extends AsyncQueryHandler {
        public BackgroundQueryHandler(ContentResolver contentResolver) {
            super(contentResolver);
        }

        //下面就是查询结束后对返回数据的处理，完成界面更新。
        @Override
        protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
            switch (token) {
                case FOLDER_NOTE_LIST_QUERY_TOKEN:
                    mNotesListAdapter.changeCursor(cursor);
                    break;
                case FOLDER_LIST_QUERY_TOKEN:
                    if (cursor != null && cursor.getCount() > 0) {
                        showFolderListMenu(cursor);
                    } else {
                        Log.e(TAG, "Query folder failed");
                    }
                    break;
                default:
                    return;
            }
        }
    }


    //通过游标显示文件夹列表菜单，功能为移动便签至某个文件件
    private void showFolderListMenu(Cursor cursor) {
        AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
        builder.setTitle(R.string.menu_title_select_folder);
        final FoldersListAdapter adapter = new FoldersListAdapter(this, cursor);
        builder.setAdapter(adapter, new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog, int which) {
                DataUtils.batchMoveToFolder(mContentResolver,
                        mNotesListAdapter.getSelectedItemIds(), adapter.getItemId(which));
                Toast.makeText(
                        NotesListActivity.this,
                        getString(R.string.format_move_notes_to_folder,
                                mNotesListAdapter.getSelectedCount(),
                                adapter.getFolderName(NotesListActivity.this, which)),
                        Toast.LENGTH_SHORT).show();
                mModeCallBack.finishActionMode();
            }
        });
        builder.show();
    }

    //创建新便签。主要是创建intent并启动。
    private void createNewNote() {
        Intent intent = new Intent(this, NoteEditActivity.class);
        intent.setAction(Intent.ACTION_INSERT_OR_EDIT);
        intent.putExtra(Notes.INTENT_EXTRA_FOLDER_ID, mCurrentFolderId);
        this.startActivityForResult(intent, REQUEST_CODE_NEW_NODE);
    }


    //批处理删除。用于多个标签删除时
    private void batchDelete() {
        new AsyncTask<Void, Void, HashSet<AppWidgetAttribute>>() {
            protected HashSet<AppWidgetAttribute> doInBackground(Void... unused) {
                HashSet<AppWidgetAttribute> widgets = mNotesListAdapter.getSelectedWidget();
                if (!isSyncMode()) {
                    // if not synced, delete notes directly
                    if (DataUtils.batchDeleteNotes(mContentResolver, mNotesListAdapter
                            .getSelectedItemIds())) {
                    } else {
                        Log.e(TAG, "Delete notes error, should not happens");
                    }
                } else {
                    // in sync mode, we'll move the deleted note into the trash
                    // folder
                    if (!DataUtils.batchMoveToFolder(mContentResolver, mNotesListAdapter
                            .getSelectedItemIds(), Notes.ID_TRASH_FOLER)) {
                        Log.e(TAG, "Move notes to trash folder error, should not happens");
                    }
                }
                return widgets;
            }

            @Override
            protected void onPostExecute(HashSet<AppWidgetAttribute> widgets) {
                if (widgets != null) {
                    for (AppWidgetAttribute widget : widgets) {
                        if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
                                && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
                            updateWidget(widget.widgetId, widget.widgetType);
                        }
                    }
                }
                mModeCallBack.finishActionMode();
            }
        }.execute();
    }

    //文件夹删除功能
    private void deleteFolder(long folderId) {
        if (folderId == Notes.ID_ROOT_FOLDER) {
            Log.e(TAG, "Wrong folder id, should not happen " + folderId);
            return;
        }

        HashSet<Long> ids = new HashSet<Long>();
        ids.add(folderId);
        HashSet<AppWidgetAttribute> widgets = DataUtils.getFolderNoteWidget(mContentResolver,
                folderId);
        if (!isSyncMode()) {
            // if not synced, delete folder directly
            DataUtils.batchDeleteNotes(mContentResolver, ids);
        } else {
            // in sync mode, we'll move the deleted folder into the trash folder
            DataUtils.batchMoveToFolder(mContentResolver, ids, Notes.ID_TRASH_FOLER);
        }
        if (widgets != null) {
            for (AppWidgetAttribute widget : widgets) {
                if (widget.widgetId != AppWidgetManager.INVALID_APPWIDGET_ID
                        && widget.widgetType != Notes.TYPE_WIDGET_INVALIDE) {
                    updateWidget(widget.widgetId, widget.widgetType);
                }
            }
        }
    }

    //打开便签功能。形参为NoteItemData，其为文件夹或便签的实例。
    private void openNode(NoteItemData data) {
        Intent intent = new Intent(this, NoteEditActivity.class);
        intent.setAction(Intent.ACTION_VIEW);
        intent.putExtra(Intent.EXTRA_UID, data.getId());
        this.startActivityForResult(intent, REQUEST_CODE_OPEN_NODE);
    }

    //打开文件夹功能
    private void openFolder(NoteItemData data) {
        mCurrentFolderId = data.getId();
        startAsyncNotesListQuery();
        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
            mState = ListEditState.CALL_RECORD_FOLDER;
            mAddNewNote.setVisibility(View.GONE);
        } else {
            mState = ListEditState.SUB_FOLDER;
        }
        if (data.getId() == Notes.ID_CALL_RECORD_FOLDER) {
            mTitleBar.setText(R.string.call_record_folder_name);
        } else {
            mTitleBar.setText(data.getSnippet());
        }
        mTitleBar.setVisibility(View.VISIBLE);
    }

    //视图点击事件。实现创建便签。

    public void onClick(View v) {
        if (v.getId() == R.id.btn_new_note) {
            createNewNote();
        }
    }

    //显示软键盘
    private void showSoftInput() {
        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputMethodManager != null) {
            inputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
        }
    }
    //不显示软键盘
    private void hideSoftInput(View view) {
        InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }

    //文件夹新建、查看及重命名功能。
    private void showCreateOrModifyFolderDialog(final boolean create) {
        final AlertDialog.Builder builder = new AlertDialog.Builder(this);
        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_text, null);
        final EditText etName = (EditText) view.findViewById(R.id.et_foler_name);
        showSoftInput();
        if (!create) {
            if (mFocusNoteDataItem != null) {
                etName.setText(mFocusNoteDataItem.getSnippet());
                builder.setTitle(getString(R.string.menu_folder_change_name));
            } else {
                Log.e(TAG, "The long click data item is null");
                return;
            }
        } else {
            etName.setText("");
            builder.setTitle(this.getString(R.string.menu_create_folder));
        }

        builder.setPositiveButton(android.R.string.ok, null);
        builder.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                hideSoftInput(etName);
            }
        });

        final Dialog dialog = builder.setView(view).show();
        final Button positive = (Button)dialog.findViewById(android.R.id.button1);
        positive.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                hideSoftInput(etName);
                String name = etName.getText().toString();
                if (DataUtils.checkVisibleFolderName(mContentResolver, name)) {
                    Toast.makeText(NotesListActivity.this, getString(R.string.folder_exist, name),
                            Toast.LENGTH_LONG).show();
                    etName.setSelection(0, etName.length());
                    return;
                }
                if (!create) {
                    if (!TextUtils.isEmpty(name)) {
                        ContentValues values = new ContentValues();
                        values.put(NoteColumns.SNIPPET, name);
                        values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
                        values.put(NoteColumns.LOCAL_MODIFIED, 1);
                        mContentResolver.update(Notes.CONTENT_NOTE_URI, values, NoteColumns.ID
                                + "=?", new String[] {
                            String.valueOf(mFocusNoteDataItem.getId())
                        });
                    }
                } else if (!TextUtils.isEmpty(name)) {
                    ContentValues values = new ContentValues();
                    values.put(NoteColumns.SNIPPET, name);
                    values.put(NoteColumns.TYPE, Notes.TYPE_FOLDER);
                    mContentResolver.insert(Notes.CONTENT_NOTE_URI, values);
                }
                dialog.dismiss();
            }
        });

        if (TextUtils.isEmpty(etName.getText())) {
            positive.setEnabled(false);
        }
        /**
         * When the name edit text is null, disable the positive button
         */
        etName.addTextChangedListener(new TextWatcher() {
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before, int count) {
                if (TextUtils.isEmpty(etName.getText())) {
                    positive.setEnabled(false);
                } else {
                    positive.setEnabled(true);
                }
            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub

            }
        });
    }
    //用于处理子Acitivity返回父Activity。相当于对按下“返回箭头”的处理。即返回NotesListActivity活动。
    @Override
    public void onBackPressed() {
        switch (mState) {
            case SUB_FOLDER:
                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
                mState = ListEditState.NOTE_LIST;
                startAsyncNotesListQuery();
                mTitleBar.setVisibility(View.GONE);
                break;
            case CALL_RECORD_FOLDER:
                mCurrentFolderId = Notes.ID_ROOT_FOLDER;
                mState = ListEditState.NOTE_LIST;
                mAddNewNote.setVisibility(View.VISIBLE);
                mTitleBar.setVisibility(View.GONE);
                startAsyncNotesListQuery();
                break;
            case NOTE_LIST:
                super.onBackPressed();
                break;
            default:
                break;
        }
    }

    //更新小组件。
    private void updateWidget(int appWidgetId, int appWidgetType) {
        Intent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
        if (appWidgetType == Notes.TYPE_WIDGET_2X) {
            intent.setClass(this, NoteWidgetProvider_2x.class);
        } else if (appWidgetType == Notes.TYPE_WIDGET_4X) {
            intent.setClass(this, NoteWidgetProvider_4x.class);
        } else {
            Log.e(TAG, "Unspported widget type");
            return;
        }

        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, new int[] {
            appWidgetId
        });

        sendBroadcast(intent);
        setResult(RESULT_OK, intent);
    }

    //查看、删除、修改文件夹名称的浮动菜单栏（ContextMenu）创建（就是长按后出现）
    private final OnCreateContextMenuListener mFolderOnCreateContextMenuListener = new OnCreateContextMenuListener() {
        //创建ContextMenu，形参为创建的菜单、长按事件绑定的视图、视图元素信息
        public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
            if (mFocusNoteDataItem != null) {
                menu.setHeaderTitle(mFocusNoteDataItem.getSnippet());
                menu.add(0, MENU_FOLDER_VIEW, 0, R.string.menu_folder_view);
                menu.add(0, MENU_FOLDER_DELETE, 0, R.string.menu_folder_delete);
                menu.add(0, MENU_FOLDER_CHANGE_NAME, 0, R.string.menu_folder_change_name);
            }
        }
    };

    //下面都是对浮动菜单栏的一些函数
    //浮动菜单栏关闭
    @Override
    public void onContextMenuClosed(Menu menu) {
        if (mNotesListView != null) {
            mNotesListView.setOnCreateContextMenuListener(null);
        }
        super.onContextMenuClosed(menu);
    }
    //浮动菜单栏点击按钮后事件处理。

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        if (mFocusNoteDataItem == null) {
            Log.e(TAG, "The long click data item is null");
            return false;
        }
        switch (item.getItemId()) {
            case MENU_FOLDER_VIEW:
                openFolder(mFocusNoteDataItem);
                break;
            case MENU_FOLDER_DELETE:
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setTitle(getString(R.string.alert_title_delete));
                builder.setIcon(android.R.drawable.ic_dialog_alert);
                builder.setMessage(getString(R.string.alert_message_delete_folder));
                builder.setPositiveButton(android.R.string.ok,
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int which) {
                                deleteFolder(mFocusNoteDataItem.getId());
                            }
                        });
                builder.setNegativeButton(android.R.string.cancel, null);
                builder.show();
                break;
            case MENU_FOLDER_CHANGE_NAME:
                showCreateOrModifyFolderDialog(false);
                break;
            default:
                break;
        }

        return true;
    }

    //下面是OptionsMenu菜单创建的有关函数。
    //OptionsMenu创建
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        menu.clear();
        if (mState == ListEditState.NOTE_LIST) {
            getMenuInflater().inflate(R.menu.note_list, menu);
            // set sync or sync_cancel
            menu.findItem(R.id.menu_sync).setTitle(
                    GTaskSyncService.isSyncing() ? R.string.menu_sync_cancel : R.string.menu_sync);
        } else if (mState == ListEditState.SUB_FOLDER) {
            getMenuInflater().inflate(R.menu.sub_folder, menu);
        } else if (mState == ListEditState.CALL_RECORD_FOLDER) {
            getMenuInflater().inflate(R.menu.call_record_folder, menu);
        } else {
            Log.e(TAG, "Wrong state:" + mState);
        }
        return true;
    }

    //OptionsMenu点击按钮事件处理
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int itemId = item.getItemId();
        if (itemId == R.id.menu_new_folder) {
            showCreateOrModifyFolderDialog(true);
        } else if (itemId == R.id.menu_export_text) {
            exportNoteToText();
        } else if (itemId == R.id.menu_sync) {
            if (isSyncMode()) {
                if (TextUtils.equals(item.getTitle(), getString(R.string.menu_sync))) {
                    GTaskSyncService.startSync(this);
                } else {
                    GTaskSyncService.cancelSync(this);
                }
            } else {
                startPreferenceActivity();
            }
        } else if (itemId == R.id.menu_setting) {
            startPreferenceActivity();
        } else if (itemId == R.id.menu_new_note) {
            createNewNote();
        } else if (itemId == R.id.menu_search) {
            onSearchRequested();
        }
        return true;
    }

    //搜索栏功能实现（就是最上面那个搜索便签得的）
    //（内部调用了搜索的ui组件）
    @Override
    public boolean onSearchRequested() {
        startSearch(null, false, null /* appData */, false);
        return true;
    }

    //下面使用了异步线程类AsynTask。可在类中可以直接进行UI操作，并将后台计算的结果及时的交给UI线程进行UI界面显示。
    //将便签内容输出为文本
    private void exportNoteToText() {
        final BackupUtils backup = BackupUtils.getInstance(NotesListActivity.this);
        new AsyncTask<Void, Void, Integer>() {

            @Override
            protected Integer doInBackground(Void... unused) {
                return backup.exportToText();
            }

            @Override
            protected void onPostExecute(Integer result) {
                if (result == BackupUtils.STATE_SD_CARD_UNMOUONTED) {
                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
                    builder.setTitle(NotesListActivity.this
                            .getString(R.string.failed_sdcard_export));
                    builder.setMessage(NotesListActivity.this
                            .getString(R.string.error_sdcard_unmounted));
                    builder.setPositiveButton(android.R.string.ok, null);
                    builder.show();
                } else if (result == BackupUtils.STATE_SUCCESS) {
                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
                    builder.setTitle(NotesListActivity.this
                            .getString(R.string.success_sdcard_export));
                    builder.setMessage(NotesListActivity.this.getString(
                            R.string.format_exported_file_location, backup
                                    .getExportedTextFileName(), backup.getExportedTextFileDir()));
                    builder.setPositiveButton(android.R.string.ok, null);
                    builder.show();
                } else if (result == BackupUtils.STATE_SYSTEM_ERROR) {
                    AlertDialog.Builder builder = new AlertDialog.Builder(NotesListActivity.this);
                    builder.setTitle(NotesListActivity.this
                            .getString(R.string.failed_sdcard_export));
                    builder.setMessage(NotesListActivity.this
                            .getString(R.string.error_sdcard_export));
                    builder.setPositiveButton(android.R.string.ok, null);
                    builder.show();
                }
            }

        }.execute();
    }

    private boolean isSyncMode() {
        return NotesPreferenceActivity.getSyncAccountName(this).trim().length() > 0;
    }

    //用于跳转到保存的设置界面。这个maybe在isSyncMode==0时调用。作用在没进行过保存设置时。
    private void startPreferenceActivity() {
        Activity from = getParent() != null ? getParent() : this;
        Intent intent = new Intent(from, NotesPreferenceActivity.class);
        from.startActivityIfNeeded(intent, -1);
    }

    //点击事件监听类
    private class OnListItemClickListener implements OnItemClickListener {

        //点击事件处理。将点击事件其与视图绑定。
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (view instanceof NotesListItem) {
                NoteItemData item = ((NotesListItem) view).getItemData();
                if (mNotesListAdapter.isInChoiceMode()) {
                    if (item.getType() == Notes.TYPE_NOTE) {
                        position = position - mNotesListView.getHeaderViewsCount();
                        mModeCallBack.onItemCheckedStateChanged(null, position, id,
                                !mNotesListAdapter.isSelectedItem(position));
                    }
                    return;
                }

                switch (mState) {
                    case NOTE_LIST:
                        if (item.getType() == Notes.TYPE_FOLDER
                                || item.getType() == Notes.TYPE_SYSTEM) {
                            openFolder(item);
                        } else if (item.getType() == Notes.TYPE_NOTE) {
                            openNode(item);
                        } else {
                            Log.e(TAG, "Wrong note type in NOTE_LIST");
                        }
                        break;
                    case SUB_FOLDER:
                    case CALL_RECORD_FOLDER:
                        if (item.getType() == Notes.TYPE_NOTE) {
                            openNode(item);
                        } else {
                            Log.e(TAG, "Wrong note type in SUB_FOLDER");
                        }
                        break;
                    default:
                        break;
                }
            }
        }

    }


    private void startQueryDestinationFolders() {
        String selection = NoteColumns.TYPE + "=? AND " + NoteColumns.PARENT_ID + "<>? AND " + NoteColumns.ID + "<>?";
        selection = (mState == ListEditState.NOTE_LIST) ? selection:
            "(" + selection + ") OR (" + NoteColumns.ID + "=" + Notes.ID_ROOT_FOLDER + ")";

        mBackgroundQueryHandler.startQuery(FOLDER_LIST_QUERY_TOKEN,
                null,
                Notes.CONTENT_NOTE_URI,
                FoldersListAdapter.PROJECTION,
                selection,
                new String[] {
                        String.valueOf(Notes.TYPE_FOLDER),
                        String.valueOf(Notes.ID_TRASH_FOLER),
                        String.valueOf(mCurrentFolderId)
                },
                NoteColumns.MODIFIED_DATE + " DESC");
    }

    //处理长按事件。
    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
        if (view instanceof NotesListItem) {
            mFocusNoteDataItem = ((NotesListItem) view).getItemData();
            if (mFocusNoteDataItem.getType() == Notes.TYPE_NOTE && !mNotesListAdapter.isInChoiceMode()) {
                if (mNotesListView.startActionMode(mModeCallBack) != null) {
                    mModeCallBack.onItemCheckedStateChanged(null, position, id, true);
                    mNotesListView.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
                } else {
                    Log.e(TAG, "startActionMode fails");
                }
            } else if (mFocusNoteDataItem.getType() == Notes.TYPE_FOLDER) {
                mNotesListView.setOnCreateContextMenuListener(mFolderOnCreateContextMenuListener);
            }
        }
        return false;
    }
}