Using AudioManager interferes with call audio

Question

I'm using the following code in a BroadcastReceiver (phone state listener) to enable speakerphone:

final Handler mHandler = new Handler();
mHandler.postDelayed(new Runnable() {
    @Override
    public void run() {
        AudioManager audioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
        audioManager.setMode(AudioManager.MODE_IN_CALL);
        audioManager.setSpeakerphoneOn(true);
    }
}, 500);

This happens when a new outgoing call is initiated via my app. When the call is disconnected, I turn speakerphone off:

AudioManager audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
audioManager.setMode(AudioManager.MODE_NORMAL);
audioManager.setSpeakerphoneOn(false);

This all seems to work well...the first time. Afterward, my phone's audio streams seem to be tangled up into a mess. Subsequent calls are strangely silent, even calls made from outside my app's code (where the settings above are not triggered). I can get call audio back seemingly at random, but I'm not sure what causes it to return.

Any ideas on what I could be doing wrong? Is there an Android bug I'm not aware of? How can I avoid silencing my audio for subsequent calls?

EDIT: I'm testing on a Galaxy S4.

Answer 1

I have solved this issue. It seems the code that was screwing up my audio was this line:

audioManager.setMode(AudioManager.MODE_IN_CALL);

I had used this method because I couldn't get the speakerphone setting to engage successfully without it (I found a suggestion to set the mode in another Stack Overflow answer...it worked, but had problematic consequences).

All I really had to do was remove this line and increase the handler delay from 500 to 2000.

I've also maintained a static reference to the AudioManager as suggested in this answer. It doesn't seem to be necessary in this particular case, but better safe than sorry.

Answer 2

First of, I will copy this text from the documentation of setMode, just to be sure you are having it into account:

The audio mode encompasses audio routing AND the behavior of the telephony layer.
Therefore this method should only be used by applications that replace the platform-wide 
management of audio settings or the main telephony application

In other words, only une application on the system should be toying with this kind of methods. If done otherwise, consistency is not assured.

Then I would check your different audio streams in case you have some of them too low ( STREAM_VOICE_CALL, STREAM_SYSTEM, STREAM_RING, STREAM_MUSIC or STREAM_ALARM). And maybe try to use setStreamMute instead of setSpeakerphoneOn.

It would be helpful to know if your application is in fact replacing the platform-wide management of audio settings or the main telephony application