Question

Greetings,

I’m almost finished developing my Android app, however I’d like to be able to give the user the option to run it minimised in the background and be alerted whenever some event happens.

However, I don’t really know where to start. I’m trying to get an icon to show up on the status bar, to no avail. Essentially I’d like functionality similar to the ‘Trapster’ app where a little icon appears and the app notifies you when you’re approaching a speed camera!

Here’s the code I have sofar:

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;

public class Background extends Service{

    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }
    @Override
    public void onCreate() {
          super.onCreate();
          Toast.makeText(this,"Service created ...", Toast.LENGTH_LONG).show();
    }

    @Override
    public void onDestroy() {
          super.onDestroy();
          Toast.makeText(this, "Service destroyed ...", Toast.LENGTH_LONG).show();
    }
}

Also, is it necessary to set some permission to use a service? Here’s what I have in my manifest file:

<uses-permission
    android:name="android.permission.ACCESS_BACKGROUND_SERVICE" />

Answer 1

You’re on a good way, so far. Building what you need requires various steps :

• Creating a Service, like you began to do. Tha Javadoc for this class explains how a service works a lot better than be, so I’ll let you read it.
• To display an icon in the status bar, use NotificationManager in your Service.
• Lastly, the question comes of when to launch your service. You have two possibility :
  • Launching it in your activity, and letting the service work : this is when you have to do a long operation, and want to keep user informed of what happens
  • Launching it periodically, and then letting it come back to sleep : use this method if you only need to check something periodically. For this usage, you can use AlarmManager