Cheesesquare-master с пользовательским списком Retrofit

Question

Я хочу изменить Cheesesquare-master Git Link cheesesquare-master

со списком загрузки с моего сайта с помощью Retrofit

https://www.youtube.com/watch?v=FFHGkuWUsXg

http://www.jsonschema2pojo.org/

Но, к сожалению, я не могу загрузить с моего сайта.

Этот файл MainActivity.java по умолчанию является основной активностью Cheesesquare.Я только что изменил класс фрагмента адаптера (FoodListFragment).

That Foodlist fragment class initially set by random list using setupRecyclerView
recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(getActivity(),
               getRandomSublist(Cheeses.sCheeseStrings, 5)));

Здесь я хочу изменить случайный список для загрузки из Интернета.

My MainActivity.java

    private void setupViewPager(ViewPager viewPager) {
        Adapter adapter = new Adapter(getSupportFragmentManager());
        adapter.addFragment(new CheeseListFragment(), "Home");
        adapter.addFragment(new FoodListFragment(), "Message");
        //adapter.addFragment(new FoodlistAdapter(), "Message");
        adapter.addFragment(new CheeseListFragment(), "Home Work");
        viewPager.setAdapter(adapter);
    }

FoodListFragment.Java

    public class FoodListFragment extends Fragment {

        private RecyclerView mProductRView;
        private LinearLayoutManager mLayoutManager;
        private ArrayList<LoadAbout> mProductList = new ArrayList<>() ;
        private FoodlistAdapter mProductAdapter;
        private APIInterface mAPIInterfacel;

        @Nullable
        @Override
        public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            RecyclerView rv = (RecyclerView) inflater.inflate(
                    R.layout.fragment_food_list, container, false);
             setupRecyclerView(rv);
            fetchData(); //Here i got calling error
//Error Description : Java.lang.NullPointerException: Attempt to invoke interface method 'retrofit2.Call com.test.myapp.Main.APIInterface.getProduct()' on a null object reference   

            return rv;

        }

        private void fetchData() {
            mAPIInterfacel.getProduct().enqueue(new Callback<ArrayList<LoadAbout>>() {
                @Override
                public void onResponse(Call<ArrayList<LoadAbout>> call, retrofit2.Response<ArrayList<LoadAbout>> response) {
                    mProductList.addAll(response.body());
                    mProductAdapter.notifyDataSetChanged();
                }

                @Override
                public void onFailure(Call<ArrayList<LoadAbout>> call, Throwable t) {
                    Log.d("Error G", "Test: ");
                }
            });
        }



        private void setupRecyclerView(RecyclerView recyclerView) {

            recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
            //recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(getActivity(),
            //        getRandomSublist(Cheeses.sCheeseStrings, 5)));
            //mProductAdapter = new FoodlistAdapter(this.mProductList);
            //fetchData();
            recyclerView.setAdapter(new FoodlistAdapter(getActivity(), mProductList) );

        }

        private List<String> getRandomSublist(String[] array, int amount) {
    //        ArrayList<String> list = new ArrayList<>(amount);
    //        Random random = new Random();
    //        while (list.size() < amount) {
    //            //list.add(array[random.nextInt(array.length)]);
    //            list.add("1 to 5");
    //        }
            List<String> list = Arrays.asList( array );
            return list;
        }

        public static class SimpleStringRecyclerViewAdapter
                extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {

            private final TypedValue mTypedValue = new TypedValue();
            private int mBackground;
            private List<String> mValues;

            public static class ViewHolder extends RecyclerView.ViewHolder {
                public String mBoundString;

                public final View mView;
                //public final ImageView mImageView;
                public final TextView mTextView;
                public final TextView mTextView2;

                public ViewHolder(View view) {
                    super(view);
                    mView = view;
                    //mImageView = view.findViewById(R.id.avatar);
                    mTextView = view.findViewById(android.R.id.text1);
                    mTextView2 = view.findViewById(android.R.id.text2);
                }

                @Override
                public String toString() {
                    return super.toString() + " '" + mTextView.getText();
                }
            }

            public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {
                context.getTheme().resolveAttribute(R.attr.selectableItemBackground, mTypedValue, true);
                mBackground = mTypedValue.resourceId;
                mValues = items;
            }

            @Override
            public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                View view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.food_list_item, parent, false);
                view.setBackgroundResource(mBackground);
                return new ViewHolder(view);
            }

            @Override
            public void onBindViewHolder(@NonNull final ViewHolder holder, int position) {
                holder.mBoundString = mValues.get(position);
                holder.mTextView.setText(mValues.get(position));
                final int img_pos = position;
                holder.mView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Context context = v.getContext();
                        if (img_pos == 0) {

                        } else {


                        }

                    }
                });

                RequestOptions options = new RequestOptions();

            }

            @Override
            public int getItemCount() {
                return mValues.size();
            }
        }
    }

FoodlistAdapter.java

public class FoodlistAdapter extends RecyclerView.Adapter<FoodlistAdapter.MyViewHolder> {
    private Context mContext;
    private ArrayList<LoadAbout> mItemList;
    public FoodlistAdapter (Context con, ArrayList<LoadAbout> list) {

        this.mContext = con;
        this.mItemList = list;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.fragment_food_list, viewGroup, false);
        //return null;
        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, int i) {
        LoadAbout item = mItemList.get(i);
        myViewHolder.mnameTxt.setText(item.getMessage());
    }

    @Override
    public int getItemCount() {
        //return 0;
        return mItemList.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView mnameTxt;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            mnameTxt = (TextView)itemView.findViewById(R.id.text1);
        }
    }
}

food_list_item.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:state_focused="false"
    android:gravity="center_vertical">

    <TextView
        android:id="@+id/name_text"
        android:paddingRight="@dimen/album_title_padding"
        android:paddingLeft="@dimen/album_title_padding"
        android:paddingTop="@dimen/album_title_padding"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:textAppearance="@style/TextAppearance.AppCompat.Title"/>

    <android.support.v7.widget.CardView
        style="@style/Widget.CardContent"
        android:focusable="false"
        android:focusableInTouchMode="false"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="@dimen/album_top"
        android:layout_marginTop="@dimen/album_title"
        android:layout_marginLeft="@dimen/album_title"
        android:layout_marginRight="@dimen/album_title" >
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="@dimen/album_margin"
        android:orientation="vertical">

        <TextView
            android:id="@+id/text1"
            android:paddingRight="@dimen/album_title_padding"
            android:paddingLeft="@dimen/album_title_padding"
            android:paddingTop="@dimen/album_title_padding"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="15sp"
            android:textAppearance="@style/TextAppearance.AppCompat.Title"/>

        <TextView
            android:id="@android:id/text2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingRight="@dimen/album_title_padding"
            android:paddingLeft="@dimen/album_title_padding"
            android:paddingTop="@dimen/album_title_padding"
            android:paddingBottom="@dimen/album_title_padding"
            android:text="@string/cheese_ipsum" />

    </LinearLayout>

    </android.support.v7.widget.CardView>
</LinearLayout>

APIInterface.java

import java.util.ArrayList;

import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.POST;

public interface APIInterface {
    @GET("about.php")
    Call<ArrayList<LoadAbout>> getProduct();
}

APIClient.java

import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class APIClient {
    private static Retrofit retrofit = null;
    public static Retrofit getClient(){
        retrofit = new Retrofit.Builder()
                .baseUrl("http://app.themaxtech.com/api/test/")
        .addConverterFactory(GsonConverterFactory.create())
        .build();
        return retrofit;
    }

LoadAbout.java

import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class LoadAbout {

    @SerializedName("success")
    @Expose
    private Integer success;
    @SerializedName("message")
    @Expose
    private String message;
    @SerializedName("poststr")
    @Expose
    private List<Poststr> poststr = null;

    public Integer getSuccess() {
        return success;
    }

    public void setSuccess(Integer success) {
        this.success = success;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public List<Poststr> getPoststr() {
        return poststr;
    }

    public void setPoststr(List<Poststr> poststr) {
        this.poststr = poststr;
    }
}

Poststr.java

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Poststr {

    @SerializedName("dat")
    @Expose
    private String dat;
    @SerializedName("des")
    @Expose
    private String des;

    public String getDat() {
        return dat;
    }

    public void setDat(String dat) {
        this.dat = dat;
    }

    public String getDes() {
        return des;
    }

    public void setDes(String des) {
        this.des = des;
    }

}