Question

I have written a simple activity to test out services and broacast receivers and a service to go along with it. In order to know whether or not it’s working I’ve set up a Toast within the main activity to be showed once the OnReceive() method is called. But for the life of me I can’t get this to work.

These are the codes:

public class ServicesAndBroadcastIntentActivity extends Activity {

private Toast test;
private Intent intent;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    intent = new Intent(this,serviceD.class);
    test = Toast.makeText(this,"Test",Toast.LENGTH_LONG);
    test.setGravity(Gravity.CENTER,0,0);
}

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver(){
    @Override
    public void onReceive(Context context, Intent intent) {
        test.setText((intent.getStringExtra("EXTRA_MSG")));
        test.show();
    }
};


@Override
public void onResume(){
    super.onResume();
    startService(intent);
    registerReceiver(broadcastReceiver, new IntentFilter(serviceD.BROADCAST_ACTION));
}

@Override
public void onPause() {
    super.onPause();
    unregisterReceiver(broadcastReceiver);
    stopService(intent);        
}

}

public class serviceD extends Service{

private Intent intent;
static final String BROADCAST_ACTION = "com.mejg.ServicesAndBroadcastIntent";

public void onCreate() {
    super.onCreate();
    intent = new Intent(BROADCAST_ACTION);  
}

public void onStart(){
    intent.putExtra("EXTRA_MSG","hola");
    sendBroadcast(intent);
    stopSelf();
}

@Override
public IBinder onBind(Intent arg0) {
    // TODO Auto-generated method stub
    return null;
}

}

Answer 1

You are calling startService() before registerReceiver(). Both are asynchronous operations, but they will still likely occur in sequence. Hence, onStart() of your service will be called before registerReceiver() does its work, which means your broadcast goes out before your receiver is set up.

For this sort of experimentation, I recommend setting up a basic UI (e.g., one really big button) and doing the startService() call when the button is pressed.

Also, since the service calls stopSelf(), you do not need to call stopService() from the activity.

Also also, you might consider using LocalBroadcastManager for this — same basic syntax with better performance and security, since it all stays within your process.

UPDATE

Also also also, onStart() has been deprecated for two-plus years, and your method signature for it is wrong, anyway. Please use onStartCommand(), with the right parameters.

Also also also also, use @Override when overriding methods, to help you catch these sorts of problems.