android - 通过 AudioManager 访问音频设置会导致其他应用程序的音量降低？

Question

在我正在开发的应用程序中，当前台服务发生更新时，我们必须通过蜂鸣声通知用户。

我们使用这个 foreground service用于录音。要播放哔哔声，我们使用扬声器。我们在播放 beep 之前启用电话扬声器，并在 beep 完全播放时禁用，如下所示:

    stopSoundPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                @Override
                public void onCompletion(MediaPlayer mediaPlayer) {
                    SpeakerManager.get().disable();
                    .....
                }
            });
            SpeakerManager.get().enable();
            stopSoundPlayer.start();

我在 list 中有以下权限:

// Audio related permissions
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

// Other permissions
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

运行时录音权限管理得当。

但是当我的应用程序安装在任何手机上时，它会自动降低所有其他正在播放音频的应用程序的音量。当我卸载我的应用程序时，音频音量会恢复。可能是什么原因造成的？

下面是我的 SpeakerManager 类供引用:

public class SpeakerManager {

    private static SpeakerManager instance;

    private final AudioManager audioManager;

    private SpeakerManager(Context context) {
        audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
        audioManager.setMode(AudioManager.STREAM_MUSIC);
    }

    public static void init(Context context) {
        instance = new SpeakerManager(context);
    }

    public static SpeakerManager get() {
        if (instance == null) {
            throw new IllegalStateException("SpeakerManager should be initialized by calling init()");
        }
        return instance;
    }

    public void enable() {
        if (null != audioManager) {
            audioManager.setSpeakerphoneOn(true);
        }
    }

    public void disable() {
        if (null != audioManager) {
            audioManager.setSpeakerphoneOn(false);
        }
    }
}

Answer 1

尝试下面播放哔声

public final class BeepManager {

    private static final String TAG = BeepManager.class.getSimpleName();

    private static final float BEEP_VOLUME = 0.10f;

    private final Context context;

    public BeepManager(Activity activity) {
        activity.setVolumeControlStream(AudioManager.STREAM_MUSIC);

        // We do not keep a reference to the Activity itself, to prevent leaks
        this.context = activity.getApplicationContext();
    }


    public void playBeepSound() {
        AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);

        if (am != null) {
            switch (am.getRingerMode()) {
                case AudioManager.RINGER_MODE_SILENT:
                case AudioManager.RINGER_MODE_VIBRATE:
                    return;
            }
        }

        MediaPlayer mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
                mp.stop();
                mp.release();
            }
        });
        mediaPlayer.setOnErrorListener(new MediaPlayer.OnErrorListener() {
            @Override
            public boolean onError(MediaPlayer mp, int what, int extra) {
                Log.w(TAG, "Failed to beep " + what + ", " + extra);
                // possibly media player error, so release and recreate
                mp.stop();
                mp.release();
                return true;
            }
        });
        try {
            AssetFileDescriptor file = context.getResources().openRawResourceFd(R.raw.beep_sound);
            try {
                mediaPlayer.setDataSource(file.getFileDescriptor(), file.getStartOffset(), file.getLength());
            } finally {
                file.close();
            }
            mediaPlayer.setVolume(BEEP_VOLUME, BEEP_VOLUME);
            mediaPlayer.prepare();
            mediaPlayer.start();
        } catch (IOException ioe) {
            Log.w(TAG, ioe);
            mediaPlayer.release();
        }
    }
}