Develop Reference

how to control the sound volume of my own android app

I imagine the answer to this question must be something quite typical. The point is that I have some buttons that play sounds when you click on them. I want to control the sound volume. How do I control the sound volume? I am using the following code:
private fun playSound() {
val sound = getSystemService(Context.AUDIO_SERVICE) as AudioManager
sound.playSoundEffect(AudioManager.FX_KEY_CLICK, 1f)
}

https://developer.android.com/reference/android/media/AudioManager#playSoundEffect(int,%20float)
volume float: Sound effect volume. The volume value is a raw scalar so UI controls should be scaled logarithmically. If a volume of -1 is specified, the AudioManager.STREAM_MUSIC stream volume minus 3dB will be used. NOTE: This version is for applications that have their own settings panel for enabling and controlling volume.
So you need to adjust that second parameter. I haven't used it, but it says that's a scalar so I'd imagine 1 is full volume? It doesn't mention any other value as a max constant or anything. -1 gives you a sound a little quieter than the current media volume setting, if that's convenient. You'll need to play around with different values between 0 and 1 (I assume!) and see what you need

How to Change Sound Programmatically on Android

I have a media player which plays song files. However, no matter how I try to initialize its volume, the only way to change it is manually with the volume buttons. I've tried
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
int maxVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_ALARM);
mAudioManager.setStreamVolume(AudioManager.STREAM_ALARM, maxVolume, 0); // Sets volume to max
and even
mMediaPlayer.setVolume(1, 1);
but none work. I've used this code in the past without problem. I've tried my app on both 5.1.1 and 7.1.1 and no luck. It doesn't matter whether the phone's volume starts in a muted state or not. I checked and maxVolume is non-zero (I've tried just hardcoding numbers too). How can I set the initial volume programmatically? The media player starts playing automatically. (I've tried calling this within the media player's onPrepared listener too in case it made a difference. It doesn't.) I also checked whether the phone volume is "fixed". It's not.
How can I get my player to start playing at max volume (no matter what the phone was set for)?

I found the problem. I had the stream wrong. Instead of STREAM_ALARM it should have been STREAM_MUSIC. The list of streams can be found here:
https://developer.android.com/reference/android/media/AudioManager.html

Get media player to play first on right speaker and then on left speaker

I would like to play an audio file that starts on the left speaker and then switches to the right speaker.
I have tried doing something like this:
MediaPlayer mp = new MediaPlayer();
// Setup audio file
mp.start();
mp.setVolume(1.0F, 0F);
// Delay a second or two (I actually use a Handler and the postDelayed method)
mp.setVolume(0F, 1.0F);
but the sound comes through on both speakers the whole time.
How can I play audio in Android with either the left or right speaker muted (or at reduced volume)?
EDIT:
I got the correct behavior for a while while I was testing my app, but then it returned to what I described above with the exact same code base. Based on this, is there anything else I could check to find out what's going on?

One option would be
Start mediaplayer with setVolume(1.0F, 0F);
When you want to switch to other speaker, get current position of media player by using getCurrentPosition() method.
Then stop media player.
Then again start with setVolume(0F,1.0F);
Seek to the positin you got in 2nd step using seekTo() method
Done.
Overhead:This method may cause you some delay

It looks like you are doing it correctly according to the Android API http://developer.android.com/reference/android/media/MediaPlayer.html
public void setVolume (float leftVolume, float rightVolume)
Sets the volume on this player. This API is recommended for balancing the output of
audio streams within an application. Unless you are writing an application to control
user settings, this API should be used in preference to setStreamVolume(int, int, int)
which sets the volume of ALL streams of a particular type. Note that the passed volume
values are raw scalars in range 0.0 to 1.0. UI controls should be scaled logarithmically.
Parameters
leftVolume left volume scalar
rightVolume right volume scalar
My best advice is to try 0.0F instead of just 0F and then maybe trying to set the volume before you start playing the track then transition while it's playing.

Android Media Player setVolume Issues

Until now, I was setting my MediaPlayer volume by setting the stream volume. I don't want to do that anymore because it messes with user settings. I now take the value from a SeekBar (0 to 100) and do valueFromSeekBar / 100 to get a float between 0 and 1 to use in MediaPlayer.setVolume(float, float).
The problem is that the volume level doesn't seem to change. Here is how I set up the MediaPlayer:
player.setAudioStreamType(AudioManager.STREAM_ALARM);
player.setLooping(true);
player.prepare();
float alarmVolume = AudioUtils.getMediaPlayerScaledVolume(100, alarm.volume);
if(NetworkUtils.isInCall(context)) {
alarmVolume = IN_CALL_VOLUME;
}
mediaPlayer.setVolume(alarmVolume, alarmVolume); //I've even tried hardcoding 0.1f
No matter what I do, it seems like the value I put in MediaPlayer.setVolume gets ignored, and the volume of the stream (in this case the alarm stream) gets used instead. It's most noticeable when the stream volume is set to max, and I play two audio files, one with MediaPlayer.setVolume(1f, 1f) and the other with MediaPlayer.setVolume(0.01f, 0.01f). They are almost indistinguishable from one another. I need a way for my users to be able to position the SeekBar at 1 and get a barely audible sound, or at 100 and have the max sound. Is this possible or am I gonna have to go back to messing with streams?

Set volume:
it will set maximum value(100) to Alarm Stream.
amanager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
mediaPlayer.setAudioStreamType(AudioManager.STREAM_ALARM);
amanager.setStreamVolume(AudioManager.STREAM_ALARM, amanager.getStreamMaxVolume(AudioManager.STREAM_ALARM), AudioManager.FLAG_PLAY_SOUND);

Can it be you have two objects "player" and "mediaPlayer"? Here I just used that API, and it works as was to be expected.

Controlling the volume of forced-to-speaker audio

I'm playing an audio clip using OpenSL ES. In my code I have
audioManager.setMode(AudioManager.MODE_IN_CALL);
audioManager.setSpeakerphoneOn(true);
to force audio through the speaker while the headset is plugged in. It works fine, but I can't control the volume. Pressing the volume buttons while the clip is playing makes the volume seekbar appear and move, but the volume doesn't change.
Calling setVolumeControlStream(AudioManager.STREAM_VOICE_CALL) or setVolumeControlStream(AudioManager.STREAM_MUSIC) before playing doesn't seem to help.
Changing any of the volumes outside of my app (e.g. in the Android settings) doesn't affect the playing volume. Volume control works well on both headset and speaker when no routing is applied.
I've also tried routing the audio to the speaker using this code I found in another answer
Class audioSystemClass = Class.forName("android.media.AudioSystem");
Method setForceUse = audioSystemClass.getMethod("setForceUse", int.class, int.class);
// First 1 == FOR_MEDIA, second 1 == FORCE_SPEAKER. To go back to the default
// behavior, use FORCE_NONE (0).
setForceUse.invoke(null, 1, 1);
but it doesn't work on my Android 4.3 Nexus 4. I need the most compatible way to to that anyway.
Any ideas?
Thanks.

Here is a couple ideas:
MODE_IN_CALL sets all sorts of priority/policy on STREAM_VOICE_CALL. During this time, other STREAM may loose volume control focus. See if your audio clip is played over STREAM_VOICE_CALL.
MODE_IN_COMMUNICATION (for VoIP) may be a better fit for you. MODE_IN_CALL is for cellular call and can degrade your audio quality.
You may want to try grab audio focus and see if that helps. http://developer.android.com/training/managing-audio/audio-focus.html