Calling activity class method from Service class

Question

I have seen many posts in SO regarding this but could not get the exact and most easy way to call an activity method from service class. Is broadcast receiver only the option? No easy way out ? I just need to call the following method in Activity class after the media player is prepared in Service class .

Activity class:

    public void updateProgress() {
    // set Progress bar values
    songProgressBar.setProgress(0);
    songProgressBar.setMax(100);
    // Updating progress bar
    updateProgressBar();
}

Service class:

   @Override
public IBinder onBind(Intent intent) {
    Log.d(this.getClass().getName(), "BIND");
    return musicBind;
}

@Override
public boolean onUnbind(Intent intent) {
    return false;
}
    @Override
public void onPrepared(MediaPlayer mp) {
    try {
        mp.start();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    }

           // updateProgress();// Need to call the Activity method here 
  }

Answer 1

You can't call your sevices method direcly from your activity or vise versa. There are 3 ways to communicate with a service; using broadcasters and receivers, using Messenger or binding to the service. For further information look at http://developer.android.com/guide/components/bound-services.html

Answer 2

I created a general class called Delegate (it's not a special name, you can name it John) and passed MainActivity class into it as a static field. Then I can access it from the service since its global now. I am not sure if it is cost-effective but it solved the problem for me simple.

My service:

package com.some.package;
import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.FirebaseInstanceIdService;

public class FirebaseInstanceIDService extends FirebaseInstanceIdService {

    @Override
    public void onTokenRefresh() {
        String token = FirebaseInstanceId.getInstance().getToken();
        Delegate.theMainActivity.onDeviceTokenChange(token);
    }
}

Delegate class:

package com.some.package;

public class Delegate {
    static MainActivity theMainActivity;
}

What I did in MainActivity:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Delegate.theMainActivity = this;

    //rest of the code...
}

public void onDeviceTokenChange(String token){
    Log.e("updated token:", token);
}

Answer 3

Define an interface your Service will use to communicate events:

public interface ServiceCallbacks {
    void doSomething();
} 

Write your Service class. Your Activity will bind to this service, so follow the sample shown here. In addition, we will add a method to set the ServiceCallbacks.

public class MyService extends Service {
    // Binder given to clients
    private final IBinder binder = new LocalBinder();
    // Registered callbacks
    private ServiceCallbacks serviceCallbacks;


    // Class used for the client Binder.
    public class LocalBinder extends Binder {
        MyService getService() {
            // Return this instance of MyService so clients can call public methods
            return MyService.this;
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    public void setCallbacks(ServiceCallbacks callbacks) {
        serviceCallbacks = callbacks;
    }
}

Write your Activity class following the same guide, but also make it implement your ServiceCallbacks interface. When you bind/unbind from the Service, you will register/unregister it by calling setCallbacks on the Service.

public class MyActivity extends Activity implements ServiceCallbacks {
    private MyService myService;
    private boolean bound = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(...);
    }

    @Override
    protected void onStart() {
        super.onStart();
        // bind to Service
        Intent intent = new Intent(this, MyService.class);
        bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
    }

    @Override
    protected void onStop() {
        super.onStop();
        // Unbind from service
        if (bound) {
            myService.setCallbacks(null); // unregister
            unbindService(serviceConnection);
            bound = false;
        }
    }

    /** Callbacks for service binding, passed to bindService() */
    private ServiceConnection serviceConnection = new ServiceConnection() {

        @Override
        public void onServiceConnected(ComponentName className, IBinder service) {
            // cast the IBinder and get MyService instance
            LocalBinder binder = (LocalBinder) service;
            myService = binder.getService();
            bound = true;
            myService.setCallbacks(MyActivity.this); // register
        }

        @Override
        public void onServiceDisconnected(ComponentName arg0) {
            bound = false;
        }
    };

    /* Defined by ServiceCallbacks interface */
    @Override
    public void doSomething() {
        ...
    }
}

Now when your service wants to communicate back to the activity, just call one of the interface methods from earlier. Inside your service:

if (serviceCallbacks != null) { 
    serviceCallbacks.doSomething();
}

Answer 4

Use Broadcast receiver with service for updating your view from the service class. For example:

1. In my activity class

   public class ServiceDemoActivity extends Activity {
   
       Intent intent;
       /** Called when the activity is first created. */
       @Override
       public void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.main);
           final TextView notification = (TextView) findViewById(R.id.notification);
           if (CheckIfServiceIsRunning()) {
   
           } else {
               startService(new Intent(this, MyService.class));
           }
       }
   
       private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
           @Override
           public void onReceive(Context context, Intent intent) {
               updateDate(intent);
           }
       };
   
       private void updateDate(Intent intent) {
           String time = intent.getStringExtra("time");
           Toast.makeText(getApplicationContext(), "Yea!!! Service called", Toast.LENGTH_SHORT).show();
           TextView date = (TextView) findViewById(R.id.date);
           date.setText(time);
       }
   
       @Override
       public void onResume() {
           super.onResume();
           registerReceiver(broadcastReceiver, new IntentFilter(
                   MyService.BROADCAST_ACTION));
       }
   }
   

   And in my service class I am calling my update ui after a few interval of time which updates my UI.

   public class MyService extends Service {    
   
           public static final String
           BROADCAST_ACTION = "com.mukesh.service";    
           private final Handler handler = new Handler();
   
   
           @Override
           public void onCreate() {
   
               intent = new Intent(BROADCAST_ACTION);
           }
   
           @Override   
           public void onDestroy() {
   
               stopService(intent);
           }
   
           @Override
           public void onStart(Intent intent, int startid) {
               int i = 0;
               while (i <= 2) {
                   if (i > 1) {
                       i++;
                       this.onDestroy();
                   } else {
                       counter = i;
                       i++;
                       handler.removeCallbacks(sendUpdatesToUI);
                       handler.postDelayed(sendUpdatesToUI, 1 * 1000); // 1 sec
                   }
               }       
           }
   
           private Runnable sendUpdatesToUI = new Runnable() {
               public void run() {
                   DisplayLoggingInfo();           
                           handler.postDelayed(this, 7 * 1000); // 7 sec
               }
           };
   
           private void DisplayLoggingInfo() {  
               intent.putExtra("time", new Date().toLocaleString());
               intent.putExtra("counter", String.valueOf(counter));
               sendBroadcast(intent);
               stopService(intent);
           }
    }
   

For complete code check this link

Answer 5

You can call a method of activity from service by implementing your own listener like this https://stackoverflow.com/a/18585247/5361964

You might consider running your activity method in runOnUiThread like this:

    // method will be called from service
    override fun callback(activity: Activity, result: String) {
        runOnUiThread{
            Toast.makeText(activity, result, Toast.LENGTH_LONG).show()
        }
    }

Answer 6

You can call from your service

 getContentResolver().notifyChange(uri, null);

and in your activity you set up a

getContentResolver().registerContentObserver(uri, false, new ContentObserver(getHandler())
{
    public void onChange(boolean selfChange)
    {
        updateProgress()
    }
};

the onChange method will ba called on the UI thread