Merged in tiagokcshibata/love-android-sdl2 (pull request #8)

Add GameActivity.hasBackgroundMusic

Approved-by: Tiago Shibata <tiago.shibata@tapps.com.br>
Approved-by: Bart van Strien <bart.bes+projects@gmail.com>

love/src/main/java/org/love2d/android/GameActivity.java

@@ -18,6 +18,7 @@ import android.app.ProgressDialog;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.media.AudioManager;
 import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Build;
@@ -27,6 +28,7 @@ import android.os.Handler;
 import android.os.PowerManager;
 import android.os.ResultReceiver;
 import android.os.Vibrator;
+import android.support.annotation.Keep;
 import android.util.Log;
 import android.util.DisplayMetrics;
 import android.widget.Toast;
@@ -250,4 +252,10 @@ public class GameActivity extends SDLActivity {
 
       Log.d("GameActivity", "Copied " + bytes_written + " bytes");
     }
+
+    @Keep
+    public boolean hasBackgroundMusic() {
+      AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
+      return audioManager.isMusicActive();
+    }
 }