How to Add our own System Service in Android Framework?

Question

I am new to android and i have been analyzing the android source code to understand how the System services are implemented. My Question is am I able to create my own System Se

Answer 1

public class MyService extends Service {

    private static MyService instance = null;

    public static boolean isInstanceCreated(){
        return instance != null;
    }
    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }
    @Override     
    public void onStart(Intent intent, int startId) {
        super.onStart(intent, startId); 
        //Toast.makeText(this, "onStart", Toast.LENGTH_SHORT).show();
        } 
    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
        new Thread(threadBody).start();
    }
    @Override     
    public void onDestroy() {
        instance = null;
    }
}

In your activity:

if(!MyService.isInstanceCreated())
        startService(new Intent(YourActivityClassName.this, MyService.class));