[android] bind/unbind service example (android)

Add these methods to your Activity:

private MyService myServiceBinder;
public ServiceConnection myConnection = new ServiceConnection() {

    public void onServiceConnected(ComponentName className, IBinder binder) {
        myServiceBinder = ((MyService.MyBinder) binder).getService();
        Log.d("ServiceConnection","connected");
        showServiceData();
    }

    public void onServiceDisconnected(ComponentName className) {
        Log.d("ServiceConnection","disconnected");
        myService = null;
    }
};

public Handler myHandler = new Handler() {
    public void handleMessage(Message message) {
        Bundle data = message.getData();
    }
};

public void doBindService() {
    Intent intent = null;
    intent = new Intent(this, BTService.class);
    // Create a new Messenger for the communication back
    // From the Service to the Activity
    Messenger messenger = new Messenger(myHandler);
    intent.putExtra("MESSENGER", messenger);

    bindService(intent, myConnection, Context.BIND_AUTO_CREATE);
}

And you can bind to service by ovverriding onResume(), and onPause() at your Activity class.

@Override
protected void onResume() {

    Log.d("activity", "onResume");
    if (myService == null) {
        doBindService();
    }
    super.onResume();
}

@Override
protected void onPause() {
    //FIXME put back

    Log.d("activity", "onPause");
    if (myService != null) {
        unbindService(myConnection);
        myService = null;
    }
    super.onPause();
}

Note, that when binding to a service only the onCreate() method is called in the service class. In your Service class you need to define the myBinder method:

private final IBinder mBinder = new MyBinder();
private Messenger outMessenger;

@Override
public IBinder onBind(Intent arg0) {
    Bundle extras = arg0.getExtras();
    Log.d("service","onBind");
    // Get messager from the Activity
    if (extras != null) {
        Log.d("service","onBind with extra");
        outMessenger = (Messenger) extras.get("MESSENGER");
    }
    return mBinder;
}

public class MyBinder extends Binder {
    MyService getService() {
        return MyService.this;
    }
}

After you defined these methods you can reach the methods of your service at your Activity:

private void showServiceData() {  
    myServiceBinder.myMethod();
}

and finally you can start your service when some event occurs like _BOOT_COMPLETED_

public class MyReciever  extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (action.equals("android.intent.action.BOOT_COMPLETED")) {
            Intent service = new Intent(context, myService.class);
            context.startService(service);
        }
    }
}

note that when starting a service the onCreate() and onStartCommand() is called in service class and you can stop your service when another event occurs by stopService() note that your event listener should be registerd in your Android manifest file:

<receiver android:name="MyReciever" android:enabled="true" android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
</receiver>