Android Application stops working at start, stack trace doesn't point to where in the code it stops working

Question

I'm trying to get my feet wet in Android programming developing a really basic application that integrates with Facebook. I followed the tutorial for making a basic login page, but the application just crashes at the start. I tried to debug it myself, but after a few hours I haven't run into any success. What's also really killing me is that the error messages don't directly tell me where exactly in my code I'm screwing up, and I guess I lack the understanding to know what they're saying right now.

(https://developers.facebook.com/docs/android/login-with-facebook/v2.2#step1)

Here are the errors(and I apologize for the wall of text) and my MainActivity/MainFragment classes. If anybody could point out what specific mistake (or if I'm just approaching the entire thing wrong) I made, that would be really awesome. Also, any tips for just general debugging of Android apps and problems like this would be really appreciated too. My mind still hasn't completely wrapped around the activity lifecycle and their methods.

Logcat:

  01-13 05:31:14.216  17714-17730/com.example.harrisonhe.chatstats W/dalvikvm﹕ threadid=12: thread    exiting with uncaught exception (group=0x41e44e30)
  01-13 05:31:14.216  17714-17731/com.example.harrisonhe.chatstats W/dalvikvm﹕ threadid=13: thread      exiting with uncaught exception (group=0x41e44e30)
  01-13 05:31:14.216  17714-17730/com.example.harrisonhe.chatstats E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.example.harrisonhe.chatstats, PID: 17714
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:300)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:864)
 Caused by: java.lang.NullPointerException
        at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:911)
        at com.facebook.internal.Utility.queryAppSettings(Utility.java:673)
        at com.facebook.widget.LoginButton$1.doInBackground(LoginButton.java:678)
        at com.facebook.widget.LoginButton$1.doInBackground(LoginButton.java:675)
        at android.os.AsyncTask$2.call(AsyncTask.java:288)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:864)
        01-13 05:31:14.226  17714-17731/com.example.harrisonhe.chatstats E/AndroidRuntime_2_crash﹕ crash in the same process: AsyncTask #2
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:300)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
                     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:864)
 Caused by: java.lang.NullPointerException
        at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:911)
        at com.facebook.internal.Utility.queryAppSettings(Utility.java:673)
        at com.facebook.widget.LoginButton$1.doInBackground(LoginButton.java:678)
        at com.facebook.widget.LoginButton$1.doInBackground(LoginButton.java:675)
        at android.os.AsyncTask$2.call(AsyncTask.java:288)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:864)

Code:

public class MainActivity extends FragmentActivity {

private MainFragment mainFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if(savedInstanceState==null)
    {
        //add fragment on initial activity startup
        mainFragment = new MainFragment();
        getSupportFragmentManager().beginTransaction().add(android.R.id.content, mainFragment).commit();

    }
    else
    {
        // Or set the fragment from restored state info
        mainFragment = (MainFragment) getSupportFragmentManager().findFragmentById(android.R.id.content);
    }

    setContentView(R.layout.activity_main);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

public class MainFragment extends Fragment{

private static final String TAG = "MainFragment";
// @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.activity_main, container, false);

    LoginButton authButton = (LoginButton) view.findViewById(R.id.authButton);
    authButton.setFragment(this);
    return view;
}

private Session.StatusCallback callback = new Session.StatusCallback() {
    public void call(Session session, SessionState state, Exception exception) {
        onSessionStateChange(session, state, exception);
    }
};

private void onSessionStateChange(Session session, SessionState state, Exception exception) {
    if (state.isOpened()) {
        Log.i(TAG,"swag420");
        Log.i(TAG, "Logged in...");
    } else if (state.isClosed()) {
        Log.i(TAG, "Logged out...");
    }
}

private UiLifecycleHelper uiHelper;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    uiHelper = new UiLifecycleHelper(getActivity(), callback);
}

@Override
public void onResume(){
    super.onResume();
    /*
     for scenarios where the main activity is launched and user session is
     not null, the session state change notification may not be triggered.
     Trigger it if it's open/closed
    */
    Session session = Session.getActiveSession();
    if(session!=null && (session.isOpened() || session.isClosed()))
    {
        onSessionStateChange(session, session.getState(), null);
    }
    uiHelper.onResume();
   }

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
    super.onActivityResult(resultCode, resultCode, data);
    uiHelper.onActivityResult(requestCode,resultCode,data);
}

@Override
public void onPause(){
    super.onPause();
    uiHelper.onDestroy();
}

@Override
public void onSaveInstanceState(Bundle outState){
    super.onSaveInstanceState(outState);
    uiHelper.onSaveInstanceState(outState);
  }
}

NullPointerException thrown at LoginButton.java line no 678/675 — PPD, Jan 13 '15 at 11:01

score 0 · Answer 1 · edited May 23 '17 at 11:57

0

At least you know what the problem is, maybe not where it is. It is a null pointer somewhere. Looking at your code I can't pinpoint the problem this answer as a reference. In this answer, the person did not initialize the jsonParser that allowed them to connect to the internet. I'm assuming that there are other classes you are not displaying

This was also in the answer I linked to:

Also you can not make Network requests on the UIThread. This will cause a NetworkOnMainThreadException. You will need to use an AsyncTask. Check this NetworkOnMainThreadException

edited May 23 '17 at 11:57

Community

1
1

answered Jan 13 '15 at 11:14

Rgw3d

61
6

That's the exact thread that I tried to debug with earlier, but unfortunately I couldn't really get much from it. I only have the two classes which I posted - are there other areas in my program that I should be looking in? The only other ones I really edited were the gradle build file and activity_main. – Mikey Chen Jan 13 '15 at 11:18
Maybe test to see if the uiHelper is null? – Rgw3d Jan 13 '15 at 12:08

score 0 · Answer 2 · answered Jan 14 '15 at 18:06

0

The LoginButton needs your app ID to be set in the metadata (AndroidManifest.xml and strings.xml). Have you setup your app ID accordingly? https://developers.facebook.com/docs/android/getting-started

answered Jan 14 '15 at 18:06

Ming Li

15,672
3
37
35

Android Application stops working at start, stack trace doesn't point to where in the code it stops working

2 Answers2