How to shut off the sound MediaRecorder plays when the state changes

Question

My Android application uses MediaRecorder on a SurfaceHolder to show a live preview of what the camera is capturing. Every time the user presses the REC button on the app, t

Answer 1

Following on from @wired00's answer, the code can be simplified as follows:

private void setMuteAll(boolean mute) {
    AudioManager manager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

    int[] streams = new int[] { AudioManager.STREAM_ALARM,
        AudioManager.STREAM_DTMF, AudioManager.STREAM_MUSIC,
        AudioManager.STREAM_RING, AudioManager.STREAM_SYSTEM,
        AudioManager.STREAM_VOICE_CALL };

    for (int stream : streams)
        manager.setStreamMute(stream, mute);
}

This works fine for now but if more streams are introduced in the future, this method may need updating. A more robust approach (though perhaps overkill) is to use reflection to get all the STREAM_* static fields:

List streams = new ArrayList();
Field[] fields = AudioManager.class.getFields();
for (Field field : fields) {
     if (field.getName().startsWith("STREAM_")
         && Modifier.isStatic(field.getModifiers())
         && field.getType() == int.class) {
         try {
             Integer stream = (Integer) field.get(null);
             streams.add(stream);
         } catch (IllegalArgumentException e) {
              // do nothing
         } catch (IllegalAccessException e) {
             // do nothing
        }
    }
}

Interestingly, there seem to be some streams that are not documented, namely STREAM_BLUETOOTH_SCO, STREAM_SYSTEM_ENFORCED and STREAM_TTS. I'm guessing/hoping there's no harm in muting these too!