Inclusion of onStart Method causes Null Pointer Exception

Question

I'm trying to bind a service in my main activity and am getting a null pointer exception. In order to bind the service, i've added onStart() and onStop() methods to the activity, which in themselves seem to be causing the null pointer exception. That's the conclusion i've come to through careful commenting out of lines of code.

Just to be clear, and also I suppose to provide further detail:

Does not Cause Null Pointer Exception:

   public class MainActivity extends Activity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    public VivaClientService VivaClient;    
    private static final String TAG = "Viva_MainActivity";
    private Intent ClientIntent;
    private ServiceConnection ClientConnect = new ServiceConnection(){
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
                Log.d(TAG, "service connected");
                LocalBinder binder = (LocalBinder)service;
                VivaClient = binder.getService();
            }
            @Override
            public void onServiceDisconnected(ComponentName name) {
                Log.d(TAG, "service disconnected");
            }
     };

    //Fragment managing the behaviors, interactions and presentation of the navigation drawer.
    private NavigationDrawerFragment mNavigationDrawerFragment;

    //Used to store the last screen title. For use in {@link #restoreActionBar()}.
    private CharSequence mTitle;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mNavigationDrawerFragment = (NavigationDrawerFragment)
                getFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
                R.id.navigation_drawer,
                (DrawerLayout) findViewById(R.id.drawer_layout));

        ClientIntent = new Intent(this, VivaClientService.class);
    }

    /*
    @Override
    protected void onStart(){
        //this.bindService(ClientIntent, ClientConnect, Context.BIND_AUTO_CREATE);
        //this.startService(ClientIntent);

        //JSONObject about = VivaClient.getAbout();
        //System.out.println(about.toString());
    }


    @Override
    protected void onStop(){
    //  this.stopService(ClientIntent);
    //  this.unbindService(ClientConnect);
    }
    */

Causes Null Pointer Exception:

public class MainActivity extends Activity
        implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    public VivaClientService VivaClient;    
    private static final String TAG = "Viva_MainActivity";
    private Intent ClientIntent;
    private ServiceConnection ClientConnect = new ServiceConnection(){
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
                Log.d(TAG, "service connected");
                LocalBinder binder = (LocalBinder)service;
                VivaClient = binder.getService();
            }
            @Override
            public void onServiceDisconnected(ComponentName name) {
                Log.d(TAG, "service disconnected");
            }
     };

    //Fragment managing the behaviors, interactions and presentation of the navigation drawer.
    private NavigationDrawerFragment mNavigationDrawerFragment;

    //Used to store the last screen title. For use in {@link #restoreActionBar()}.
    private CharSequence mTitle;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mNavigationDrawerFragment = (NavigationDrawerFragment)
                getFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
                R.id.navigation_drawer,
                (DrawerLayout) findViewById(R.id.drawer_layout));

        ClientIntent = new Intent(this, VivaClientService.class);
    }


    @Override
    protected void onStart(){
        //this.bindService(ClientIntent, ClientConnect, Context.BIND_AUTO_CREATE);
        //this.startService(ClientIntent);

        //JSONObject about = VivaClient.getAbout();
        //System.out.println(about.toString());
    }


    @Override
    protected void onStop(){
    //  this.stopService(ClientIntent);
    //  this.unbindService(ClientConnect);
    }

Literally, the only difference between the two is the inclusion of the onStart and onStop methods which, when included, are blank. I don't understand why that should cause an error. Plz help ;_; thanks!

It would be helpful if you posted the error from LogCat but usually if you intend to override a method you should call the super classes method as well. Similar to what you have done with 'super.onCreate(savedInstanceState);' — Larry McKenzie, Aug 13 '14 at 18:31

score 1 · Accepted Answer · answered Aug 13 '14 at 18:32

1

You aren't calling super.onStart() or super.onStop() from your overrides which will cause the Activity to throw an exception.

answered Aug 13 '14 at 18:32

sddamico

2,130
16
13

are you sure your second example was producing a npe? please post logcat for the second example – sddamico Aug 13 '14 at 18:40

Inclusion of onStart Method causes Null Pointer Exception

1 Answers1