Question

i trying to make horizontal slider same in google play app but in Fragment below all my file include the code i have this code from other site but its not working with me - the code not make any error in android studio also its run but when open this fragment the app stop working - how to solve that plz thanks

main Fragment.java

public class SearchFragment extends Fragment  {
private static final String TAG = "SearchFragment";
private RecyclerView my_recycler_view;
private Toolbar toolbar;

private final static String TEST_URL = 
 "http://monaasoft.com/indianfm/api/test.json";
List<Data> allSampleData;



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

    View view = inflater.inflate(R.layout.fragment_search, container, 
false);
    if (toolbar != null) {

        toolbar.setTitle("G PlayStore");

    }


    fetch_category(TEST_URL);


    return view;
}

private void fetch_category(String url) {

allSampleData = new ArrayList<Data>();
toolbar = (Toolbar) toolbar.findViewById(R.id.toolbar);

AsyncHttpClient client = new AsyncHttpClient();
client.get(url, new JsonHttpResponseHandler() {

    public void onSuccess(int statusCode, PreferenceActivity.Header[] 
headers, JSONObject response) {


        if (statusCode == 200 && response != null) {
            Log.i("response-", response.toString());


            try {
                JSONArray dataArary = response.getJSONArray("data");


                for (int i = 0; i < dataArary.length(); i++) {
                    JSONObject sectionObj = (JSONObject) dataArary.get(i);

                    String title = sectionObj.getString("title");


                    List<Section> sections = new ArrayList<Section>();


                    JSONArray sectionsArray = 
  sectionObj.getJSONArray("section");

                    for (int j = 0; j < sectionsArray.length(); j++) {

                        JSONObject obj = (JSONObject) sectionsArray.get(j);


                        Section section = new Section();

                        section.setName(obj.getString("name"));
                        section.setImage(obj.getString("image"));


                        sections.add(section);
                    }


                    Data data = new Data();

                    data.setTitle(title);
                    data.setSection(sections);


                    allSampleData.add(data);


                }


            } catch (JSONException e) {
                e.printStackTrace();

            }

            if (allSampleData != null) {

                my_recycler_view = (RecyclerView) 
  my_recycler_view.findViewById(R.id.my_recycler_view);

                my_recycler_view.setHasFixedSize(true);

                RecyclerViewDataAdapter adapter = new 
RecyclerViewDataAdapter(getContext(), allSampleData);

                my_recycler_view.setLayoutManager(new 
LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));

                my_recycler_view.setAdapter(adapter);


            } else {
                Toast.makeText(getContext(), "Connection Error", 
Toast.LENGTH_SHORT).show();

            }


        }



    }



});
}
}

not get any error in code but the app is stop working
im still very new in java so may be i do too much mistake

Answer 1

But 99/100 times when this question is asked, it's a NullPointerException

Yes.

The first one is your toolbar, here it is:

private void fetch_category(String url) {

    allSampleData = new ArrayList<Data>();
    toolbar = (Toolbar) toolbar.findViewById(R.id.toolbar);  //<- here
    ...

Getting toolbar from toolbar?

You probably meant view.findViewById(R.id.toolbar), but from your current setup, you would need to first come up with a way to pass that view to it.

Good luck, and next time, please provide the stacktrace from your logcat, if you can't debug it yourself.

how to fix the app is stopped in this Fragment

1 个答案: