Question

I am getting a the following problem when I tried to bind from activity to a service.

Code for Activity and this activity is a part of TabActivity

public class SettingsActivity extends Activity{

private BkgService myBkgService;
Button BtnSubmit;

public void onCreate(Bundle savedInstanceState) {

setContentView(R.layout.settings);
BtnSubmit = (Button)findViewById(R.id.XmlBtnSubmit);
BtnSubmit.setOnClickListener(onSubmit);

Intent bindIntent = new Intent(this, BkgService.class);
bindService(bindIntent, serviceConncetion, Context.BIND_AUTO_CREATE);
}


private ServiceConnection serviceConncetion = new ServiceConnection() {

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            myBkgService = ((BkgService.MyBinder)service).getService();
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            myBkgService = null;
        }
    };

private OnClickListener onSubmit = new OnClickListener() {

        @Override
        public void onClick(View v) {
            myBkgService.startCounting();
        }
    };
}

Now My Service Code looks like this

    public class BkgService extends Service{
    private IBinder mBinder;
    private int i;


    public void onCreate() {
           super.onCreate();
    }

    @Override
    public IBinder onBind(Intent arg0) {
            return mBinder;
    }

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

    public int startCounting(){
        return i=i+1;
    }

}

Now When Click on my BtnSubmit in my activity, I am getting the NullPointerException. I checked that I am its because in myBkgService.startCounting() the myBkgService is null.I am unable to find out why I am getting this null pointer. Is my activity is not properly bound to the service. Please suggest some solution to this. I am stuck up here.

Answer 1

Make sure you declare your service in your AndroidManifest.xml. If you don’t, then the call to bindService will return false.

I also notice that you did not initialize your mBinder, something like the following is needed in your BkgService.

private IBinder mBinder = new MyBinder();