TEST1231/NoteWidgetProvider.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.widget;  
  
import android.app.PendingIntent; // 用于处理延迟执行的Intent  
import android.appwidget.AppWidgetManager; // 管理应用小部件的类  
import android.appwidget.AppWidgetProvider; // 小部件的基类  
import android.content.ContentValues; // 用于向ContentProvider提供新值  
import android.content.Context; // 提供应用环境信息的类  
import android.content.Intent; // 用于不同组件间通信的类  
import android.database.Cursor; // 用于遍历查询结果的类  
import android.util.Log; // 用于打印日志信息  
import android.widget.RemoteViews; // 用于在远程视图中更新小部件的UI  
  
import net.micode.notes.R; // 应用的资源类  
import net.micode.notes.data.Notes; // 笔记的数据访问类  
import net.micode.notes.data.Notes.NoteColumns; // 笔记数据表的列定义  
import net.micode.notes.tool.ResourceParser; // 资源解析工具类  
import net.micode.notes.ui.NoteEditActivity; // 编辑笔记的Activity  
import net.micode.notes.ui.NotesListActivity; // 笔记列表的Activity  
  
// 定义一个抽象类，用于实现自定义笔记小部件  
public abstract class NoteWidgetProvider extends AppWidgetProvider {  
    // 定义查询笔记时需要的列  
    public static final String [] PROJECTION = new String [] {  
        NoteColumns.ID, // 笔记ID  
        NoteColumns.BG_COLOR_ID, // 笔记背景颜色ID  
        NoteColumns.SNIPPET // 笔记摘要  
    };  
  
    // 定义列的索引，用于从Cursor中获取数据  
    public static final int COLUMN_ID           = 0;  
    public static final int COLUMN_BG_COLOR_ID  = 1;  
    public static final int COLUMN_SNIPPET      = 2;  
  
    // 定义日志标签  
    private static final String TAG = "NoteWidgetProvider";  
  
    // 当小部件被删除时调用  
    @Override  
    public void onDeleted(Context context, int[] appWidgetIds) {  
        // 更新被删除小部件对应的笔记中的WIDGET_ID为无效值  
        ContentValues values = new ContentValues();  
        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);  
        for (int i = 0; i < appWidgetIds.length; i++) {  
            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,  
                    values,  
                    NoteColumns.WIDGET_ID + "=?",  
                    new String[] { String.valueOf(appWidgetIds[i])});  
        }  
    }  
  
    // 根据小部件ID获取笔记信息  
    private Cursor getNoteWidgetInfo(Context context, int widgetId) {  
        return context.getContentResolver().query(Notes.CONTENT_NOTE_URI,  
                PROJECTION,  
                NoteColumns.WIDGET_ID + "=? AND " + NoteColumns.PARENT_ID + "<>?",  
                new String[] { String.valueOf(widgetId), String.valueOf(Notes.ID_TRASH_FOLER) },  
                null);  
    }  
  
    // 更新小部件的UI（公开方法）  
    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {  
        update(context, appWidgetManager, appWidgetIds, false);  
    }  
  
    // 更新小部件的UI（私有方法，支持隐私模式）  
    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,  
            boolean privacyMode) {  
        for (int i = 0; i < appWidgetIds.length; i++) {  
            if (appWidgetIds[i] != AppWidgetManager.INVALID_APPWIDGET_ID) {  
                // 获取默认背景ID和摘要文本  
                int bgId = ResourceParser.getDefaultBgId(context);  
                String snippet = "";  
                // 创建跳转到编辑笔记Activity的Intent  
                Intent intent = new Intent(context, NoteEditActivity.class);  
                intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);  
                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_ID, appWidgetIds[i]);  
                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_TYPE, getWidgetType());  
  
                // 查询小部件对应的笔记信息  
                Cursor c = getNoteWidgetInfo(context, appWidgetIds[i]);  
                if (c != null && c.moveToFirst()) {  
                    if (c.getCount() > 1) {  
                        // 如果有多条记录，打印错误日志并关闭Cursor  
                        Log.e(TAG, "Multiple message with same widget id:" + appWidgetIds[i]);  
                        c.close();  
                        return;  
                    }  
                    // 从Cursor中获取摘要和背景ID，并设置Intent的额外数据  
                    snippet = c.getString(COLUMN_SNIPPET);  
                    bgId = c.getInt(COLUMN_BG_COLOR_ID);  
                    intent.putExtra(Intent.EXTRA_UID, c.getLong(COLUMN_ID));  
                    intent.setAction(Intent.ACTION_VIEW);  
                } else {  
                    // 如果没有找到笔记，设置默认摘要文本和Intent动作  
                    snippet = context.getResources().getString(R.string.widget_havenot_content);  
                    intent.setAction(Intent.ACTION_INSERT_OR_EDIT);  
                }  
  
                // 关闭Cursor  
                if (c != null) {  
                    c.close();  
                }  
  
                // 创建RemoteViews对象并设置背景和资源  
                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());  
                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));  
                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);  
  
                // 根据隐私模式设置不同的PendingIntent  
                PendingIntent pendingIntent = null;  
                if (privacyMode) {  
                    // 隐私模式下，设置文本为提示信息，并创建跳转到笔记列表的PendingIntent  
                    rv.setTextViewText(R.id.widget_text,  
                            context.getString(R.string.widget_under_visit_mode));  
                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], new Intent(  
                            context, NotesListActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);  
                } else {  
                    // 非隐私模式下，设置文本为摘要，并创建跳转到编辑笔记的PendingIntent  
                    rv.setTextViewText(R.id.widget_text, snippet);  
                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], intent,  
                            PendingIntent.FLAG_UPDATE_CURRENT);  
                }  
  
                // 设置点击事件  
                rv.setOnClickPendingIntent(R.id.widget_text, pendingIntent);  
                // 更新小部件  
                appWidgetManager.updateAppWidget(appWidgetIds[i], rv);  
            }  
        }  
    }  
  
    // 抽象方法，用于获取背景资源的ID  
    protected abstract int getBgResourceId(int bgId);  
  
    // 抽象方法，用于获取小部件的布局ID  
    protected abstract int getLayoutId();  
  
    // 抽象方法，用于获取小部件的类型  
    protected abstract int getWidgetType();  
}