Android: Saving screen state (Beginner)

Question

I have come across an issue with my application, I have an "option" class which has a ToggleButton in it which handles the playback of music (on or off) which I created in a Session. However, if I turn the music off, change screen and go back to the option class, the ToggleButton goes back to "on", even though the music is no longer playing, which means I have to press the button twice for the music to actually come back on. Does anyone have any ideas?

Service Class:

public class MyMusicService extends Service {

MediaPlayer mp;


@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    mp = MediaPlayer.create(this, R.raw.song);


    mp.start();
    mp.setLooping(true);
    return super.onStartCommand(intent, flags, startId);
}


@Override
public IBinder onBind(Intent intent) {

    return null;
}


@Override
public void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();
    if(mp!=null) {
        mp.stop();
        mp.release();
    }
    mp=null;
}

}

Option class:

public class OptionsActivity extends Activity {

Intent i; // Handles MyMusicService.java
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.options);
    //setting the layout

    i=new Intent(this, MyMusicService.class);
    final ToggleButton soundOption = (ToggleButton) findViewById(R.id.soundPref);

    soundOption.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {   


            // Perform action on clicks to control sound being on and off.   
            if (soundOption.isChecked()) {   
                Toast.makeText(OptionsActivity.this, "Music on.", Toast.LENGTH_SHORT).show();  
                startService(i);  
            } else {   
                stopService(i);
                Toast.makeText(OptionsActivity.this, "Music off.", Toast.LENGTH_SHORT).show(); 
            }  


        }});

}

}

MainActvitiy class

Intent i;

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    //setting the layout

    //Auto starts playing music on app launch.
    i = new Intent(this,MyMusicService.class);
    startService(i);

Could it be something to do with the fact in the XML I have:

android:checked="true"

Thanks for any help.

Answer 1

Yes, the ToggleButton will be initialized anew, when you come back to this view, so android:checked="true" comes back into play.

You can use the method myToggleButton.setChecked(boolean isMusicPlaying) to reset the state of the Button. So you have to check whether the music is playing or not, when you come back to this view and set the state of the button accordingly.

---

You can use the method as described in another thread to find out if your music service is running.

private boolean isMyServiceRunning(String serviceCanonicalClassName) {
    ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
    for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
        if (serviceCanonicalClassName.equals(service.service.getClassName())) {
            return true;
        }
    }
    return false;
}

so you simply call it to find out of your service is running. And then, right after finding out where your ToggleButton is in your layout, you can define if it should be toggled or not:

boolean musicPlays = isMyServiceRunning(MyMusicService.class.getCanonicalName());
final ToggleButton soundOption = (ToggleButton) findViewById(R.id.soundPref);
soundOption.setChecked(musicPlays)