How to run Retrovit2 Json RecyclerView in fragment? - json

Question

So i using retrofit2 to fetch my json into my main activity it runs smoothly, but im using bottom navigation so i should convert my code from activity into fragment.
my code didnt show error after i debug it, it shows force close when the fragment opened
This is my Fragment Code:
package com.itsalex.helios.fragment;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.MenuItemCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.itsalex.helios.Adapter;
import com.itsalex.helios.ApiClient;
import com.itsalex.helios.ApiInterface;
import com.itsalex.helios.Contact;
import com.itsalex.helios.R;
import com.itsalex.helios.activity.CartActivity;
import com.itsalex.helios.activity.ProdukActivity;
import com.itsalex.helios.adapters.HorizontalAdapter;
import com.itsalex.helios.adapters.VerticalAdapter;
import com.itsalex.helios.model.Food;
import com.itsalex.helios.model.GeneralFood;
import com.itsalex.helios.recycleFragment;
import com.itsalex.helios.rest.RetrofitClient;
import com.itsalex.helios.rest.RetrofitInterface;
import java.util.ArrayList;
import java.util.List;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
public class StatusFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public StatusFragment() {
// Required empty public constructor
}
/*private appController mController;*/
public List<Contact> contacts;
public Adapter adapter;
private RecyclerView recyclerView;
protected Handler handler;
private ApiInterface apiInterface;
ProgressBar progressBar;
TextView search;
String[] item;
private Call<ResponseBody> result;
public static recycleFragment newInstance(String param1, String param2) {
recycleFragment fragment = new recycleFragment();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v;
v = inflater.inflate(R.layout.fragment_recycle, container, false);
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
progressBar = v.findViewById(R.id.prograss);
recyclerView = v.findViewById(R.id.frg_recyclerView);
handler = new Handler();
contacts = new ArrayList<>();
recyclerView.setHasFixedSize(true);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(mLayoutManager);
//adapter = new Adapter(getContext(), contacts, recyclerView, recyclerView, false);
adapter = new Adapter(contacts, getContext());
recyclerView.setAdapter(adapter);
fetchContact("users", "");
return v;
}
public void fetchContact(String type, String key){
apiInterface = ApiClient.getApiClient().create(ApiInterface.class);
Call<List<Contact>> call = apiInterface.getContact(type, key);
call.enqueue(new Callback<List<Contact>>() {
#Override
public void onResponse(Call<List<Contact>> call, Response<List<Contact>> response) {
progressBar.setVisibility(View.GONE);
contacts = response.body();
adapter = new Adapter(contacts, getContext());
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
#Override
public void onFailure(Call<List<Contact>> call, Throwable t) {
progressBar.setVisibility(View.GONE);
Toast.makeText(getContext(), "Error\n"+t.toString(), Toast.LENGTH_LONG).show();
}
});
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
/*if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}*/
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
this is my adapter activity
package com.itsalex.helios;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
public class Adapter extends RecyclerView.Adapter<Adapter.MyViewHolder> {
private List<Contact> contacts;
private Context context;
public Adapter(List<Contact> contacts, Context context) {
this.contacts = contacts;
this.context = context;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
return new MyViewHolder(view);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.name.setText(contacts.get(position).getName());
holder.email.setText(contacts.get(position).getEmail());
}
#Override
public int getItemCount() {
return contacts.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder{
TextView name,email;
public MyViewHolder(View itemView) {
super(itemView);
name = itemView.findViewById(R.id.name);
email = itemView.findViewById(R.id.email);
}
}
}
In the Logcat it shows error
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at com.itsalex.helios.Adapter.getItemCount(Adapter.java:40)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3722)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3527)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4082)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1077)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:132)
at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1361)
at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:894)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1702)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1556)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1465)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1702)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1556)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1465)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16992)
at android.view.ViewGroup.layout(ViewGroup.java:5409)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2483)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2185)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1314)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7057)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:829)
at android.view.Choreographer.doCallbacks(Choreographer.java:606)
at android.view.Choreographer.doFrame(Choreographer.java:576)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:815)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6934)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
i google it and i didnt find the answer, what should i do?
Thanks in advance

Answer 1

You have not initialised your progress bar.Use findViewById to set progressbar to your required progressbar.