初学《 NotificationBar》

最新推荐文章于 2022-05-01 23:02:16 发布

almo_omla

最新推荐文章于 2022-05-01 23:02:16 发布

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分类专栏：初学android

本文链接：https://blog.youkuaiyun.com/almo_omla/article/details/53436706

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这篇博客主要介绍了初学者如何理解和实现Android中的NotificationBar，通过代码示例详细解析了NotificationBar的工作原理和使用方法。

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NotificationBar的实现代码参考，上代码：

public class MusicService extends Service implements MediaPlayer.OnCompletionListener {

    private static final boolean D = true;
    private static final String TAG = MusicService.class.getSimpleName();

    private static final int HANDLER_MUSIC_PLAY = 1;
    private MediaPlayer mMediaPlayer;
    private MusicHandler mMusicHandler;
    public MusicService() {

    }

    @Override
    public void onCreate() {

        super.onCreate();
        mMediaPlayer = new MediaPlayer();
        mMediaPlayer.setOnCompletionListener(this);
        HandlerThread thread = new HandlerThread("music",Thread.NORM_PRIORITY);
        thread.start();
        Looper looper = thread.getLooper();
        mMusicHandler = new MusicHandler(looper);

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if (intent.getAction().equals(Constants.ACTION.STARTFOREGROUND_ACTION)) {
            Log.i(TAG, "Received Start Foreground Intent ");
            Intent notificationIntent = new Intent(this, MainActivity.class);
            notificationIntent.setAction(Constants.ACTION.MAIN_ACTION);
            notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                    | Intent.FLAG_ACTIVITY_CLEAR_TASK);
            PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
                    notificationIntent, 0);

            Intent previousIntent = new Intent(this, MusicService.class);
            previousIntent.setAction(Constants.ACTION.STOP_ACTION);
            PendingIntent ppreviousIntent = PendingIntent.getService(this, 0,
                    previousIntent, 0);

            Intent playIntent = new Intent(this, MusicService.class);
            playIntent.setAction(Constants.ACTION.PLAY_ACTION);
            PendingIntent pplayIntent = PendingIntent.getService(this, 0,
                    playIntent, 0);

            Intent nextIntent = new Intent(this, MusicService.class);
            nextIntent.setAction(Constants.ACTION.PAUSE_ACTION);
            PendingIntent pnextIntent = PendingIntent.getService(this, 0,
                    nextIntent, 0);

            Bitmap icon = BitmapFactory.decodeResource(getResources(),
                    R.drawable.rating_favorite);

            Notification notification = new NotificationCompat.Builder(this)
                    .setContentTitle("Truiton Music Player")
                    .setTicker("Truiton Music Player")
                    .setContentText("My Music")
                    .setSmallIcon(R.drawable.rating_favorite)
                    .setLargeIcon(
                            Bitmap.createScaledBitmap(icon, 128, 128, false))
                    .setContentIntent(pendingIntent)
                    .setOngoing(true)
                    .addAction(android.R.drawable.ic_media_previous,
                            "Stop", ppreviousIntent)
                    .addAction(android.R.drawable.ic_media_play, "Play",
                            pplayIntent)
                    .addAction(android.R.drawable.ic_media_next, "Pause",
                            pnextIntent).build();
            startForeground(Constants.NOTIFICATION_ID.FOREGROUND_SERVICE,
                    notification);

        } else if (intent.getAction().equals(Constants.ACTION.STOP_ACTION)) {
            Log.i(TAG, "Clicked Previous");
            if(mMediaPlayer.isPlaying()) {
                mMediaPlayer.stop();
                mMediaPlayer.release();
            }
        } else if (intent.getAction().equals(Constants.ACTION.PLAY_ACTION)) {
            Log.i(TAG, "Clicked Play");
            if(!mMediaPlayer.isPlaying())
                mMusicHandler.sendEmptyMessageDelayed(HANDLER_MUSIC_PLAY,3*1000);

        } else if (intent.getAction().equals(Constants.ACTION.PAUSE_ACTION)) {
            Log.i(TAG, "Clicked Next");
            if(mMediaPlayer.isPlaying())
                mMediaPlayer.pause();
            else
                mMediaPlayer.start();

        } else if (intent.getAction().equals(
                Constants.ACTION.STOPFOREGROUND_ACTION)) {
            Log.i(TAG, "Received Stop Foreground Intent");
            if(mMediaPlayer.isPlaying()) {
                mMediaPlayer.release();
            }

            stopForeground(true);
            stopSelf();
        }
        return START_STICKY;
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        return null;
    }

    @Override
    public void onCompletion(MediaPlayer mp) {
        mMediaPlayer.stop();
    }

    private class MusicHandler extends Handler {

        public MusicHandler(Looper looper) {
            super(looper);
        }

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case HANDLER_MUSIC_PLAY:
                    if(D) Log.d(TAG,"HANDLER_MUSIC_PLAY---");
                    mMediaPlayer.reset();
                    try {
                        AssetFileDescriptor fileDescriptor = getAssets().openFd
                                ("millions_of_sadness.mp3");
                        mMediaPlayer.setDataSource(fileDescriptor.getFileDescriptor(),
                                fileDescriptor.getStartOffset(), fileDescriptor.getLength());
                        mMediaPlayer.prepare();
                        mMediaPlayer.start();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                    break;
                default:
                    super.handleMessage(msg);
                    break;
            }

        }
    }
}