PendingIntent中requestCode的应用

    最近看了有关AppWidget的文档，对以前做的音乐播放器进行了修改，增加了Widget功能。效果如下：

 

    写了Widget类，继承了AppWidgetProvider，重写了onUpdate方法，如下：

@Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,
            int[] appWidgetIds) {
        //
        RemoteViews views=new RemoteViews(context.getPackageName(), R.layout.widget_layout);

        Intent upIntent=new Intent(context, MyPlayService.class);
        upIntent.putExtra("command", Command.UP);

        Intent startIntent=new Intent(context, MyPlayService.class);
        startIntent.putExtra("command", Command.START);

        Intent pauseIntent=new Intent(context, MyPlayService.class);
        pauseIntent.putExtra("command", Command.PAUSE);

        Intent stopIntent=new Intent(context, MyPlayService.class);
        stopIntent.putExtra("command", Command.STOP);

        Intent nextIntent=new Intent(context, MyPlayService.class);
        nextIntent.putExtra("command", Command.NEXT);

        Log.i(TAG, "---Intent's content---");
        Log.i(TAG, "upIntent--->"+upIntent);
        Log.i(TAG, "startIntent--->"+startIntent);
        Log.i(TAG, "pauseIntent--->"+pauseIntent);
        Log.i(TAG, "stopIntent--->"+stopIntent);
        Log.i(TAG, "nextIntent--->"+nextIntent);

        PendingIntent upPending=PendingIntent.getService(context, 0, upIntent, 0);
        PendingIntent startPending=PendingIntent.getService(context, 0, startIntent, 0);
        PendingIntent pausePending=PendingIntent.getService(context, 0, pauseIntent, 0);
        PendingIntent stopPending=PendingIntent.getService(context, 0, stopIntent, 0);
        PendingIntent nextPending=PendingIntent.getService(context, 0, nextIntent, 0);

        views.setOnClickPendingIntent(R.id.btn_up, upPending);
        views.setOnClickPendingIntent(R.id.btn_start, startPending);
        views.setOnClickPendingIntent(R.id.btn_pause, pausePending);
        views.setOnClickPendingIntent(R.id.btn_stop, stopPending);
        views.setOnClickPendingIntent(R.id.btn_next, nextPending);

        for(int i=0; i<appWidgetIds.length; i++){
            appWidgetManager.updateAppWidget(appWidgetIds[i], views);
        }

        super.onUpdate(context, appWidgetManager, appWidgetIds);
    }