test1/widget/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;  
import android.appwidget.AppWidgetManager;  
import android.appwidget.AppWidgetProvider;  
import android.content.ContentValues;  
import android.content.Context;  
import android.content.Intent;  
import android.database.Cursor;  
import android.util.Log;  
import android.widget.RemoteViews;  
  
import net.micode.notes.R;  
import net.micode.notes.data.Notes;  
import net.micode.notes.data.Notes.NoteColumns;  
import net.micode.notes.tool.ResourceParser;  
import net.micode.notes.ui.NoteEditActivity;  
import net.micode.notes.ui.NotesListActivity;  
  
// NoteWidgetProvider是一个抽象类，它扩展了AppWidgetProvider，用于处理笔记小部件的通用逻辑  
public abstract class NoteWidgetProvider extends AppWidgetProvider {  
    // 定义了用于查询笔记小部件信息的列投影  
    public static final String[] PROJECTION = new String[]{  
            NoteColumns.ID,  
            NoteColumns.BG_COLOR_ID,  
            NoteColumns.SNIPPET  
    };  
  
    // 定义了列投影的索引  
    public static final int COLUMN_ID = 0;  
    public static final int COLUMN_BG_COLOR_ID = 1;  
    public static final int COLUMN_SNIPPET = 2;  
  
    // 日志标签  
    private static final String TAG = "NoteWidgetProvider";  
  
    // 当小部件从宿主删除时调用  
    @Override  
    public void onDeleted(Context context, int[] appWidgetIds) {  
        // 更新数据库，将已删除的小部件ID设置为无效  
        ContentValues values = new ContentValues();  
        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);  
        for (int appWidgetId : appWidgetIds) {  
            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,  
                    values,  
                    NoteColumns.WIDGET_ID + "=?",  
                    new String[]{String.valueOf(appWidgetId)});  
        }  
    }  
  
    // 根据小部件ID获取笔记小部件信息  
    private Cursor getNoteWidgetInfo(Context context, int widgetId) {  
        // 查询数据库，获取与小部件ID关联的笔记信息，排除位于回收站的笔记  
        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_FOLDER)},  
                null);  
    }  
  
    // 更新小部件的通用方法（带隐私模式参数的重载方法调用不带参数的版本）  
    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {  
        update(context, appWidgetManager, appWidgetIds, false);  
    }  
  
    // 更新小部件的私有方法  
    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,  
                        boolean privacyMode) {  
        for (int appWidgetId : appWidgetIds) {  
            if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {  
                int bgId = ResourceParser.getDefaultBgId(context); // 获取默认背景ID  
                String snippet = ""; // 初始化摘要文本  
                Intent intent = new Intent(context, NoteEditActivity.class); // 创建跳转到编辑活动的意图  
                intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); // 设置活动启动标志  
                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_ID, appWidgetId); // 添加小部件ID作为额外数据  
                intent.putExtra(Notes.INTENT_EXTRA_WIDGET_TYPE, getWidgetType()); // 添加小部件类型作为额外数据  
  
                // 查询与小部件ID关联的笔记信息  
                Cursor c = getNoteWidgetInfo(context, appWidgetId);  
                if (c != null && c.moveToFirst()) {  
                    if (c.getCount() > 1) {  
                        // 如果查询结果超过一条，记录错误日志并关闭游标  
                        Log.e(TAG, "Multiple messages with same widget id:" + appWidgetId);  
                        c.close();  
                        return;  
                    }  
                    // 从游标中获取摘要文本和背景ID  
                    snippet = c.getString(COLUMN_SNIPPET);  
                    bgId = c.getInt(COLUMN_BG_COLOR_ID);  
                    // 添加笔记ID作为额外数据，并设置意图动作为查看  
                    intent.putExtra(Intent.EXTRA_UID, c.getLong(COLUMN_ID));  
                    intent.setAction(Intent.ACTION_VIEW);  
                } else {  
                    // 如果没有查询到笔记信息，则设置默认摘要文本，并设置意图动作为插入或编辑  
                    snippet = context.getResources().getString(R.string.widget_havenot_content);  
                    intent.setAction(Intent.ACTION_INSERT_OR_EDIT);  
                }  
  
                // 关闭游标（如果已打开）  
                if (c != null) {  
                    c.close();  
                }  
  
                // 创建RemoteViews对象，用于更新小部件视图  
                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());  
                // 设置小部件背景图片  
                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));  
                // 添加背景ID作为额外数据到意图中  
                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);  
  
                // 根据隐私模式生成PendingIntent  
                PendingIntent pendingIntent = null;  
                if (privacyMode) {  
                    // 如果启用隐私模式，则设置文本为隐私提示，并创建跳转到笔记列表活动的PendingIntent  
                    rv.setTextViewText(R.id.widget_text,  
                            context.getString(R.string.widget_under_visit_mode));  
                    pendingIntent = PendingIntent.getActivity(context, appWidgetId, new Intent(  
                            context, NotesListActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);  
                } else {  
                    // 否则，设置文本为摘要文本，并创建跳转到编辑活动的PendingIntent  
                    rv.setTextViewText(R.id.widget_text, snippet);  
                    pendingIntent = PendingIntent.getActivity(context, appWidgetId, intent,  
                            PendingIntent.FLAG_UPDATE_CURRENT);  
                }  
  
                // 设置点击事件的PendingIntent  
                rv.setOnClickPendingIntent(R.id.widget_text, pendingIntent);  
                // 更新小部件视图  
                appWidgetManager.updateAppWidget(appWidgetId, rv);  
            }  
        }  
    }  
  
    // 抽象方法，子类需要实现以返回背景资源ID  
    protected abstract int getBgResourceId(int bgId);  
  
    // 抽象方法，子类需要实现以返回布局资源ID  
    protected abstract int getLayoutId();  
  
    // 抽象方法，子类需要实现以返回小部件类型  
    protected abstract int getWidgetType();  
}