Finding the song/track which is currently playing in Android

For my iAndroidRemote project, I had to find the currently playing song/track in Android phone and the ability to change to next/previous song/track.

After some digging, I found that there is no documented way to do it. It depends on an undocumented way which may not work well in all Android phones.

I found an undocumented way which works for HTC phones and some other stock Android phones that are using the default music player.

I thought of sharing the code here, so that it would be useful for others and also I would know where to look for it when I need it for the next time.

Copying the aidl files

Any Android app, can play music by using the com.android.music.MediaPlaybackService class. In order to find the currently playing song, we need to create a Service which will interact with this class

In order to do that, we need to copy the IMediaPlaybackService.aidl file from the source code of the default music app. For HTC phones we need to copy the IMediaPlaybackService.aidl file inside the com.htc.music package and for other Android phones we have to copy it from the com.android.music package.

Create the following packages to your android project.

com.htc.music
com.android.music

Copy the com.htc.music.IMediaPlaybackService.aidl and com.android.music.IMediaPlaybackService.aidl files to the newly created packages.

Creating the ServiceConnection class

The next step is to create the ServiceConnection class which will allow us to interact with the MediaPlaybackService class.

Copy the following code and create the MediaPlayerServiceConnection inside your activity as an inner class.

/**
 * The service connection class that allows you to talk to the MediaPlayer Service
 * 
 * @author "Sudar Muthu (http://sudarmuthu.com)"
 *
 */
private class MediaPlayerServiceConnection implements ServiceConnection {
  	public com.htc.music.IMediaPlaybackService mServiceHtc;
  	public com.android.music.IMediaPlaybackService mServiceAndroid;

	@Override
	public void onServiceConnected(ComponentName name, IBinder service) {
		Log.i("MediaPlayerServiceConnection", "Connected! Name: " + name.getClassName());

		// This is the important line where we bind the service
  		if (isHtc)
  			mServiceHtc = com.htc.music.IMediaPlaybackService.Stub.asInterface(service);
		else
			mServiceAndroid = com.android.music.IMediaPlaybackService.Stub.asInterface(service);
	}

	/**
	 * Selects the next song
	 * 
	 * @throws RemoteException 
	 * 
	 */
	public void nextSong() throws RemoteException {
		if (isHtc) {
			mServiceHtc.next();
		} else {
			mServiceAndroid.next();
		}
	}

	/**
	 * Selects the Previous song
	 * 
	 * @throws RemoteException
	 */
	public void prevSong() throws RemoteException {
		if (isHtc) {
			mServiceHtc.prev();
		} else {
			mServiceAndroid.prev();
		}
	}

	@Override		
	public void onServiceDisconnected(ComponentName name) {
		Log.i("MediaPlayerServiceConnection", "Disconnected!");
	}
}

We are using the boolean isHtc to determine if we are on an HTC phone. We would be using this flag before invoking the methods on the ServiceConnection class.

Getting the current song

Now we can call the getTrackName() method on the corresponding object and we can get the track information.

Playing next song

To play the next song in the track we have to just call the next() method on the corresponding object

Playing Previous song

To play the previous song in the album we have to just call the prev() method on the correct object

I have created a small sample project to show the entire flow in action. You can download the project from my Github page.

For my iAndroidRemote project, I had to adjust the volume of my Android phone. I found the code after digging around a bit.

I thought of sharing the code here, so that it would be useful for others and also I would know where to look for it when I need it for the next time.

Changing the volume in Android is pretty easy. You just need to know which class and method to call.

Getting the AudioManager Instance

First you have to get an instance of the AudioManager. You can get it by calling the getSystemService method of the Context object. If you are inside an Activity, you can get the instance by making the following code

Once you have the AudioManager instance, all you have to do is to call the adjustVolume method with appropriate arguments.

Increase Volume

To increase the volume you have to pass the AudioManager.ADJUST_RAISE constant.

Reduce Volume

And to reduce the volume you have to pass the AudioManager.ADJUST_LOWER constant.

I have created a small sample project to show the entire flow in action. You can download the project from my Github page.

Night Dreaming (by Sudar)

Tag Archives: Volume