git.text/src/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;

/**
 * 便签小部件基类，定义不同尺寸小部件的通用行为
 * 子类需实现具体布局、背景资源和小部件类型的获取
 */
public abstract class NoteWidgetProvider extends AppWidgetProvider {
    // 查询便签数据时使用的字段投影
    public static final String [] PROJECTION = new String [] {
            NoteColumns.ID,           // 便签ID
            NoteColumns.BG_COLOR_ID,  // 背景颜色ID
            NoteColumns.SNIPPET       // 便签内容摘要
    };

    // 投影字段对应的索引值
    public static final int COLUMN_ID           = 0;
    public static final int COLUMN_BG_COLOR_ID  = 1;
    public static final int COLUMN_SNIPPET      = 2;

    private static final String TAG = "NoteWidgetProvider";

    /**
     * 当小部件被删除时调用
     * 清除数据库中与该小部件关联的记录
     */
    @Override
    public void onDeleted(Context context, int[] appWidgetIds) {
        ContentValues values = new ContentValues();
        // 将小部件ID设为无效值
        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        for (int i = 0; i < appWidgetIds.length; i++) {
            // 更新数据库中关联该小部件的便签记录
            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,
                    values,
                    NoteColumns.WIDGET_ID + "=?",
                    new String[] { String.valueOf(appWidgetIds[i])});
        }
    }

    /**
     * 获取与指定小部件关联的便签信息
     * @param context 上下文
     * @param widgetId 小部件ID
     * @return 包含便签信息的游标
     */
    private Cursor getNoteWidgetInfo(Context context, int widgetId) {
        return context.getContentResolver().query(Notes.CONTENT_NOTE_URI,
                PROJECTION,
                // 查询条件：小部件ID匹配且不在回收站中
                NoteColumns.WIDGET_ID + "=? AND " + NoteColumns.PARENT_ID + "<>?",
                new String[] { String.valueOf(widgetId), String.valueOf(Notes.ID_TRASH_FOLER) },
                null);
    }

    /**
     * 公开的更新方法，调用带隐私模式参数的私有更新方法
     */
    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        update(context, appWidgetManager, appWidgetIds, false);
    }

    /**
     * 核心更新方法，更新小部件的UI显示
     * @param context 上下文
     * @param appWidgetManager 小部件管理器
     * @param appWidgetIds 需要更新的小部件ID数组
     * @param privacyMode 是否隐私模式（隐藏内容）
     */
    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,
                        boolean privacyMode) {
        for (int i = 0; i < appWidgetIds.length; i++) {
            // 只处理有效的小部件ID
            if (appWidgetIds[i] != AppWidgetManager.INVALID_APPWIDGET_ID) {
                // 默认背景颜色ID
                int bgId = ResourceParser.getDefaultBgId(context);
                // 便签内容摘要
                String snippet = "";
                // 点击小部件时的跳转意图
                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());

                // 查询与当前小部件关联的便签数据
                Cursor c = getNoteWidgetInfo(context, appWidgetIds[i]);
                if (c != null && c.moveToFirst()) {
                    // 检查是否有多个便签关联到同一小部件（异常情况）
                    if (c.getCount() > 1) {
                        Log.e(TAG, "Multiple message with same widget id:" + appWidgetIds[i]);
                        c.close();
                        return;
                    }
                    // 从游标中获取数据
                    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); // 查看已有便签
                } else {
                    // 无关联便签时显示默认文本
                    snippet = context.getResources().getString(R.string.widget_havenot_content);
                    intent.setAction(Intent.ACTION_INSERT_OR_EDIT); // 新建便签
                }

                // 关闭游标释放资源
                if (c != null) {
                    c.close();
                }

                // 加载小部件布局
                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());
                // 设置背景图片
                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));
                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);

                // 创建点击事件的PendingIntent
                PendingIntent pendingIntent = null;
                if (privacyMode) {
                    // 隐私模式下显示提示文本，点击跳转至便签列表
                    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 {
                    // 正常模式下显示便签内容，点击跳转至编辑页
                    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：获取背景资源ID
     * 由子类实现不同尺寸小部件的背景资源
     */
    protected abstract int getBgResourceId(int bgId);

    /**
     * 抽象方法：获取布局ID
     * 由子类实现不同尺寸小部件的布局文件
     */
    protected abstract int getLayoutId();

    /**
     * 抽象方法：获取小部件类型
     * 由子类定义具体的小部件类型（如2x、4x等）
     */
    protected abstract int getWidgetType();
}