CODEWITHSUNDEEP
androidgridviewfragmentandroid-arrayadapter
JMGoodwin
JMGoodwin

Reputation: 80

Using GridView inside Fragment with ArrayAdapter<String>

I am creating a fragment where I want to display a simple gridview that will be generated from a StringArray. I don't need anything complicated, the basic ArrayAdapter works just fine for creating the gridview when not in a fragment. However, when I try to run it, I keep getting a nullpointerexception.

public class NarrowTopicsFragment extends Fragment {

private GridView grid;
private String narrowTopic;

@Override
public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    GridView view = (GridView) inflater.inflate(R.layout.layout_narrow_topics, container);
    return view;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {


    String[] letters = new String[] { "A", "B", "C", "D", "E",
            "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O",
            "P", "Q", "R", "S", "T",
            "U", "V", "W", "X", "Y", "Z"};

    grid = (GridView) getView().findViewById(R.id.gridView1);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, letters);
    grid.setAdapter(adapter); //FWIW, this is line 37


}

}

I've got to think it is something simple, but I can't figure it out for the life of me.

LogCat:

06-12 23:31:18.152: E/AndroidRuntime(9113): FATAL EXCEPTION: main
06-12 23:31:18.152: E/AndroidRuntime(9113): Process: com.gmail.goodwin.m.joshua.evidenceguide, PID: 9113
06-12 23:31:18.152: E/AndroidRuntime(9113): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gmail.goodwin.m.joshua.evidenceguide/com.gmail.goodwin.m.joshua.evidenceguide.EvidenceGuide}: java.lang.NullPointerException
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread.access$900(ActivityThread.java:161)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.os.Handler.dispatchMessage(Handler.java:102)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.os.Looper.loop(Looper.java:157)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread.main(ActivityThread.java:5356)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at java.lang.reflect.Method.invokeNative(Native Method)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at java.lang.reflect.Method.invoke(Method.java:515)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at dalvik.system.NativeStart.main(Native Method)
06-12 23:31:18.152: E/AndroidRuntime(9113): Caused by: java.lang.NullPointerException
06-12 23:31:18.152: E/AndroidRuntime(9113):     at com.gmail.goodwin.m.joshua.evidenceguide.NarrowTopicsFragment.onActivityCreated(NarrowTopicsFragment.java:37)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.Fragment.performActivityCreated(Fragment.java:1708)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:908)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1044)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1853)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.Activity.performCreate(Activity.java:5429)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
06-12 23:31:18.152: E/AndroidRuntime(9113):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269)

Upvotes: 2

Views: 2557

Answers (2)

Zin Win Htet
Zin Win Htet

Reputation: 2595

Try this

public class NarrowTopicFragment extends Fragment {
GridView grid;
String narrowTopic;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.layout_narrow_topics, container,
            false);

    grid = (GridView) rootView.findViewById(R.id.gridView1);

    String[] letters = new String[] { "A", "B", "C", "D", "E",
            "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O",
            "P", "Q", "R", "S", "T",
            "U", "V", "W", "X", "Y", "Z"};
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, letters);

    grid.setAdapter(adapter);
    return rootView;
}

}

Upvotes: 4

matiash
matiash

Reputation: 55380

Is gridView1 the id of the GridView in your layout file?

Anyway, a much simpler solution is to move this code into onCreateView(), i.e.

@Override
public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    GridView view = (GridView) inflater.inflate(R.layout.layout_narrow_topics, container);

    String[] letters = new String[] { "A", "B", "C", "D", "E",
            "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O",
            "P", "Q", "R", "S", "T",
            "U", "V", "W", "X", "Y", "Z"};

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, letters);
    view.setAdapter(adapter); //FWIW, this is line 37

    return view;
}

Upvotes: 0

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