Question

我正在使用以下代码在我的应用中播放声音。在ICS之前一切正常。但是在ICS和更新的版本上，虽然没有出现错误，但听不到声音。

编辑：注意，以下代码由广泛的接收器触发。 BroadCast接收器调用异步任务。在asycn任务的后处理方法中，调用以下方法。

此错误仅在特定的移动型号（例如nexus）上发生，并且在某些型号上，用户可以播放声音，这些声音附带了库存操作系统但不是他们自己放置在rigtones文件夹中的声音。

我无法了解特定手机上发生的问题

错误可能是什么？

public static void playSound(final Context context, final int volume,
            Uri uri, final int stream, int maxTime, int tickTime) {
        //stopPlaying();
        /*
        if (stream < 0 || stream > 100) {
            throw new IllegalArgumentException(
                    "volume must be between 0 and 100 .Current volume "
                            + volume);
        }*/

        final AudioManager mAudioManager = (AudioManager) context
                .getSystemService(Context.AUDIO_SERVICE);

        int deviceLocalVolume = getDeviceVolume(volume,
                mAudioManager.getStreamMaxVolume(stream));

        Log.d(TAG,
                "device max volume = "
                        + mAudioManager.getStreamMaxVolume(stream)
                        + " for streamType " + stream);
        Log.d(TAG, "playing sound " + uri.toString()
                + " with device local volume " + deviceLocalVolume);

        final int oldVolume = mAudioManager.getStreamVolume(stream);

        // set the volume to what we want it to be. In this case it's max volume
        // for the alarm stream.
        Log.d(Constants.APP_TAG, "setting device local volume to " + deviceLocalVolume);
        mAudioManager.setStreamVolume(stream, deviceLocalVolume,
                AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);

         final MediaPlayer mediaPlayer = new MediaPlayer();
         golbalMMediaPlayer = mediaPlayer;

        try {
             final OnPreparedListener OnPreparedListener = new OnPreparedListener() {

                @Override
                public void onPrepared(final MediaPlayer mp) {
                    Log.d(TAG, "onMediaPlayercompletion listener");
                    mp.start();
                    countDownTimer.start();
                }
            };

            mediaPlayer.setDataSource(context.getApplicationContext(), uri);
            mediaPlayer.setAudioStreamType(stream);
            mediaPlayer.setLooping(false);
            mediaPlayer.setOnPreparedListener(OnPreparedListener);
            mediaPlayer.setOnCompletionListener(new OnCompletionListener() {

                @Override
                public void onCompletion(MediaPlayer mp) {
                    Log.d(Constants.APP_TAG, "Entered onCompletion listener of mediaplayer");
                    mAudioManager.setStreamVolume(stream, oldVolume,
                            AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);
                    try{
                    if(mediaPlayer != null && mediaPlayer.isPlaying()){
                        mediaPlayer.release();
                    }
                    }catch(Exception ex){
                        Log.e(Constants.APP_TAG, "error on oncompletion listener" ,ex);
                    }
                }

            });

             CountDownTimer timer = new CountDownTimer(maxTime*1000, tickTime*1000) {

                @Override
                public void onTick(long millisUntilFinished) {
                    Log.d(TAG, "tick while playing sound ");
                }

                @Override
                public void onFinish() {
                    Log.d(TAG, "timer finished");
                    stopPlaying();
                }
            };

            countDownTimer = timer;

            mediaPlayer.prepareAsync();

        } catch (Exception e) {
            Log.e(TAG, "problem while playing sound", e);
        } finally {

        }
    }

日志

:07-01 00:00:00.030: D/beephourly(9500): device max volume = 7 for streamType 5
07-01 00:00:00.030: D/beephourly(9500): playing sound content://media/internal/audio/media/166 with device local volume 7
07-01 00:00:00.030: D/beephourly(9500): setting device local volume to 7
07-01 00:00:00.080: D/beephourly(9500): vibrating with pattern = [J@428bae20
07-01 00:00:00.090: D/beephourly(9500): will show normal notification
07-01 00:00:00.100: D/beephourly(9500): notification is enabled
07-01 00:00:00.100: D/usersettings(9500): hr = 0
07-01 00:00:00.110: D/beephourly(9500): onMediaPlayercompletion listener
07-01 00:00:00.451: D/beephourly(9500): tick while playing sound 
07-01 00:00:20.460: D/beephourly(9500): timer finished
07-01 00:00:20.460: D/beephourly(9500): got request to stop playing
07-01 00:00:20.460: D/beephourly(9500): cancelling countdowntimer
07-01 00:00:20.460: D/beephourly(9500): releasing mediaplayer now

此问题是我之前提出的问题的后续问题： sound not playing in android > icecream sandwich

Answer 1

您应该请求音频焦点，即使是通知也是如此。在你的情况下，它看起来像这样：

AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

//request a transient lock on the notification stream
int result = audioManager.requestAudioFocus(this, AudioManager.STREAM_NOTIFICATION,
    AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);

if (result != AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
    // could not get audio focus.
}

我怀疑在设备上运行了一些其他应用程序会给您带来请求音频焦点的问题。如果其他应用请求音频焦点，而您没有，则您的应用可能无法播放到最终流。自己请求关注将确保没有其他进程干扰您的通知声音。虽然这是在不久前推出的，但新版本的Android对使用此机制的应用程序更敏感，尤其是在后台。

说实话，当您完成通知后，您可以释放焦点：

audioManager.abandonAudioFocus(this);

声音在Android版本大于4.0时无法播放

1 个答案: