Android FragmentTransaction returns NullPointerException

Question

I'm using Android Studio 2.2.2. I have a suggestion list of items that will show every time user wants to query or search anything. Once suggested results are shown user can click on the item It should display more information about the item on the next activity however when I try to click an item the application crashes and leading me to NullPointerException error.

  public class SearchList extends Fragment implements AdapterView.OnItemClickListener {}

Imports

import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;

Logcat updated

   E/AndroidRuntime: FATAL EXCEPTION: main Process: com.sample.project, 
    PID: 3952 java.lang.NullPointerException 
    Attempt to invoke virtual method 'android.app.FragmentTransaction 
    android.app.FragmentManager.beginTransaction()' on a null object reference
    at com.sample.project.controller.SearchList.onSuggestionClick(SearchList.java:313) 
    at com.sample.project.MainActivityController$SearchSuggestionListener.onSuggestionClick(MainActivityController.java:1737) 
    at android.support.v7.widget.SearchView.onItemClicked(SearchView.java:1351)
    at android.support.v7.widget.SearchView.access$1800(SearchView.java:103)
    at android.support.v7.widget.SearchView$10.onItemClick(SearchView.java:1377)
    at android.widget.AutoCompleteTextView.performCompletion(AutoCompleteTextView.java:902)
    at android.widget.AutoCompleteTextView.access$500(AutoCompleteTextView.java:91     
    at android.widget.AutoCompleteTextView$DropDownItemClickListener.onItemClick(AutoCompleteTextView.java:1192)
    at android.widget.AdapterView.performItemClick(AdapterView.java:299)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1113)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2904)
    at android.widget.AbsListView$3.run(AbsListView.java:3638)
    at android.os.Handler.handleCallback(Handler.java:733)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5045)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)

SearchList fragment Error on line 313 - onSuggestionClick(SearchList.java:313)

  public void onSuggestionClick(int id, String mediaType, String title) {

       FragmentManager manager = getFragmentManager();

       //error on this line ---- line 313
       FragmentTransaction transaction = manager.beginTransaction();

        boolean result;
        Bundle args;
        switch (mediaType) {
            case "movie":
                activity.setRestoreMovieDetailsAdapterState(true);
                activity.setRestoreMovieDetailsState(false);
                if (movieDetails != null && lastVisitedId == id && movieDetails.getTimeOut() == 0) {

                    movieDetails.onSaveInstanceState(new Bundle());
                    Bundle bundle = new Bundle();
                    bundle.putInt("id", id);
                    Bundle save = movieDetails.getSave();
                    movieDetails = new MovieDetails();
                    movieDetails.setTimeOut(0);
                    movieDetails.setSave(save);
                    movieDetails.setArguments(bundle);
                } else movieDetails = new MovieDetails();

                args = new Bundle();
                args.putInt("id", id);
                movieDetails.setArguments(args);

                movieDetails.setTitle(title);
                transaction.replace(R.id.frame_container, movieDetails);

                result = true;
                break;

            default:
                result = false;
                break;
        }

        lastVisitedId = id;

        if (result) {
            // add the current transaction to the back stack:
            transaction.addToBackStack("movieList");
            transaction.commit();
            // collapse the search View
            ((MainActivityController) getActivity()).collapseSearchView();
        }

    }

MainActivityController Error on line 1737 - onSuggestionClick(MainActivityController.java:1737)

@Override
public boolean onSuggestionClick(int position) {
    Cursor cursor = (Cursor) searchView.getSuggestionsAdapter().getItem(position);
    if (searchView.getQuery().length() > 1)
        addSuggestion(cursor);

    //error on this line ----- line 1737
    searchList.onSuggestionClick(cursor.getInt(4), cursor.getString(5), cursor.getString(1));

    return true;
}

On the MainActivityController

private SearchList searchList = new SearchList();

Did u initialize the searchList object in MainActivityController? — Raghavendra, Nov 11 '16 at 13:01
@FilipeBorges I'm getting cannot resolve method getSupportFragmentManager() — BXUMZSE, Nov 11 '16 at 13:21
I am asking about what is the api level of device on which you are testing our code not your target version — Vivek Mishra, Nov 11 '16 at 13:24
@cricket_007 Updated logcat error. Attempt to invoke virtual method 'android.app.FragmentTransaction android.app.FragmentManager.beginTransaction()' on a null object reference — BXUMZSE, Nov 11 '16 at 16:33
you don't have a fragment manager if your fragment in not added in your activity. — njzk2, Nov 11 '16 at 16:35
Thanks for the update, but please read the link and show all the relevant code. — OneCricketeer, Nov 11 '16 at 16:38
I think you should read the [Communication with other Fragments](https://developer.android.com/training/basics/fragments/communicating.html) tutorial because you seem to want to get the Activities FragmentManager from the Fragment itself, and that is not really the recommended way to approach the problem. The Fragment should callback to the Activity, then the Activity replaces it — OneCricketeer, Nov 11 '16 at 17:17

Android FragmentTransaction returns NullPointerException

0 Answers0