getting IndexOutOfBoundException : Invalid array range 0 to 0 , So context = null, So App crashes

Question

working on InterstitialAd excercise, onClick of a button, calling tellJoke(). tellJoke() calls a AsyncTask . In AsyncTask, params size is 0 , getting IndexOutOfBundException, so context is null.

MainActivity.java

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Log.d(LOG_TAG, "after setting activity main");

}

 public static void tellJoke(View view){          
    new EndpointsAsyncTask().execute();
 }
}

MainActivityFragment.java

 public class MainActivityFragment extends Fragment {

  InterstitialAd mInterstitialAd;

  public MainActivityFragment() {
  }

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.fragment_main, container, false);

    AdView mAdView = (AdView) root.findViewById(R.id.adView);
            AdRequest adRequest = new AdRequest.Builder()
            .addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
            .build();
    mAdView.loadAd(adRequest);
    //interstitialAd part starts here
    mInterstitialAd = new InterstitialAd(getActivity());
    mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");

    mInterstitialAd.setAdListener(new AdListener() {
        @Override
        public void onAdClosed() {
            requestNewInterstitial();
            MainActivity.tellJoke(getView());
        }
    });
    return root;
}

private void requestNewInterstitial() {
    AdRequest adRequest = new AdRequest.Builder()
            .addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
            .build();

    mInterstitialAd.loadAd(adRequest);
 }
}

EndpointsAsyncTask.java

public class EndpointsAsyncTask extends AsyncTask<Context, Void, String> {

private static String LOG_TAG = EndpointsAsyncTask.class.getSimpleName();

private static MyApi myApiService = null;
private Context context ;

@Override
protected String doInBackground(Context... params) {

    if(myApiService == null) {  // Only do this once
        MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
                new AndroidJsonFactory(), null)
            .setRootUrl("https://build-it-bigger.appspot.com/_ah/api/");
        // end options for devappserver
        myApiService = builder.build();
    }       

    if (params != null) {
        context = params[0];
    }
    try {            
        return myApiService.fetchJoke().execute().getData();
    } catch (IOException e) {
        return e.getMessage();
    }
}

@Override
protected void onPostExecute(String result) {        
    if (context != null) {
        Intent intent = new Intent(context, JokeDisplayActivity.class);
        intent.putExtra(Intent.EXTRA_TEXT, result);
        context.startActivity(intent);
    }
}}

please help, where am i doing wrong ? and please suggest if other way to do this.

Answer 1

Just provide the parameter for your AsyncTask when you're calling execute (also remove static):

public void tellJoke(View view){          
   new EndpointsAsyncTask().execute(getActivity());
}

this refers to the activity and thus implements the Context interface (if called from an activity).

EDIT: Move your tellJoke method to the Fragment and call it like this:

tellJoke();

Notice that now you do not pass this but rather getActivity() since you're in a Fragment.