note/src/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.
 */

// 包声明，定义了这个类所在的包路径
package net.micode.notes.widget;

// 导入所需的Android类和接口
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;

// 导入应用特有的类和接口
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;

// 定义一个抽象类NoteWidgetProvider，继承自AppWidgetProvider，用于管理便签Widget
public abstract class NoteWidgetProvider extends AppWidgetProvider {
    // 定义查询数据库时使用的列名数组
    public static final String [] PROJECTION = new String [] {
        NoteColumns.ID,
        NoteColumns.BG_COLOR_ID,
        NoteColumns.SNIPPET
    };

    // 定义数组中每个列的索引常量
    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Widget被删除时调用的方法
    @Override
    public void onDeleted(Context context, int[] appWidgetIds) {
        // 为数据库更新准备ContentValues对象
        ContentValues values = new ContentValues();
        // 设置WIDGET_ID为无效值
        values.put(NoteColumns.WIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        // 遍历所有被删除的Widget ID
        for (int i = 0; i < appWidgetIds.length; i++) {
            // 更新数据库中对应的Widget ID为无效
            context.getContentResolver().update(Notes.CONTENT_NOTE_URI,
                    values,
                    NoteColumns.WIDGET_ID + "=?",
                    new String[] { String.valueOf(appWidgetIds[i])});
        }
    }

    // 获取与特定Widget ID相关的便签信息
    private Cursor getNoteWidgetInfo(Context context, int widgetId) {
        // 查询数据库，获取便签信息
        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Widget的方法，可以被外部调用
    protected void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        // 调用内部的update方法，不启用隐私模式
        update(context, appWidgetManager, appWidgetIds, false);
    }

    // 更新Widget的内部方法，根据是否启用隐私模式来更新Widget
    private void update(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds,
            boolean privacyMode) {
        // 遍历所有Widget ID
        for (int i = 0; i < appWidgetIds.length; i++) {
            // 如果Widget ID有效
            if (appWidgetIds[i] != AppWidgetManager.INVALID_APPWIDGET_ID) {
                // 获取默认背景ID
                int bgId = ResourceParser.getDefaultBgId(context);
                // 初始化摘要字符串
                String snippet = "";
                // 创建Intent，用于编辑便签
                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());

                // 获取便签信息的Cursor
                Cursor c = getNoteWidgetInfo(context, appWidgetIds[i]);
                // 如果Cursor不为空且第一条数据有效
                if (c != null && c.moveToFirst()) {
                    // 如果有多条数据与Widget ID匹配，记录错误日志并返回
                    if (c.getCount() > 1) {
                        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
                    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 {
                    // 如果没有找到匹配的便签，设置摘要为默认字符串
                    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，用于更新Widget视图
                RemoteViews rv = new RemoteViews(context.getPackageName(), getLayoutId());
                // 设置背景图片资源ID
                rv.setImageViewResource(R.id.widget_bg_image, getBgResourceId(bgId));
                intent.putExtra(Notes.INTENT_EXTRA_BACKGROUND_ID, bgId);
                // 生成PendingIntent，用于启动宿主Activity
                PendingIntent pendingIntent = null;
                if (privacyMode) {
                    // 如果启用隐私模式，显示隐私模式提示文本
                    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 {
                    // 否则，显示便签摘要
                    rv.setTextViewText(R.id.widget_text, snippet);
                    pendingIntent = PendingIntent.getActivity(context, appWidgetIds[i], intent,
                            PendingIntent.FLAG_UPDATE_CURRENT);
                }

                // 设置RemoteViews的PendingIntent
                rv.setOnClickPendingIntent(R.id.widget_text, pendingIntent);
                // 更新Widget
                appWidgetManager.updateAppWidget(appWidgetIds[i], rv);
            }
        }
    }

    // 抽象方法，用于获取背景资源ID
    protected abstract int getBgResourceId(int bgId);

    // 抽象方法，用于获取布局ID
    protected abstract int getLayoutId();

    // 抽象方法，用于获取Widget类型
    protected abstract int getWidgetType();
}