네트워크로부터 받은 Json 데이터에서 Json 의 array 를 RecyclerView 로 처리하는법

package com.mugoori.networkapp2;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import com.mugoori.networkapp2.adapter.PostAdapter;
import com.mugoori.networkapp2.model.Post;

import org.json.JSONArray;
import org.json.JSONException;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;
    PostAdapter adapter;
    ArrayList<Post> postList = new ArrayList<>();

    final String URL = "https://jsonplaceholder.typicode.com";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));

        DividerItemDecoration dividerItemDecoration =
                new DividerItemDecoration(getApplicationContext(),new LinearLayoutManager(this).getOrientation());
        recyclerView.addItemDecoration(dividerItemDecoration);


        // 데이터를 네트워크에서 받아온다
        RequestQueue queue = Volley.newRequestQueue(MainActivity.this);

        // request 만든다
        JsonArrayRequest request = new JsonArrayRequest(
                Request.Method.GET,
                URL + "/posts",
                null,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        try {

                            for (int i = 0; i < response.length(); i++) {

                                int userId = response.getJSONObject(i).getInt("userId");
                                int id = response.getJSONObject(i).getInt("id");
                                String title = response.getJSONObject(i).getString("title");
                                String body = response.getJSONObject(i).getString("body");
                                Post post = new Post(userId, id, title, body);
                                postList.add(post);
                            }

                            adapter = new PostAdapter(MainActivity.this, postList);
                            recyclerView.setAdapter(adapter);

                        } catch (JSONException e) {
                            Toast.makeText(MainActivity.this, "파싱오류", Toast.LENGTH_SHORT).show();
                            return;

                        }


                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                }
        );

        queue.add(request);

    }
}

# MainActivity 

 

 

 

package com.mugoori.networkapp2.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.mugoori.networkapp2.R;
import com.mugoori.networkapp2.model.Post;

import java.util.ArrayList;

public class PostAdapter extends RecyclerView.Adapter<PostAdapter.ViewHolder> {

    Context context;
    ArrayList<Post> postList;

    public PostAdapter(Context context, ArrayList<Post> postList) {
        this.context = context;
        this.postList = postList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull PostAdapter.ViewHolder holder, int position) {

        // 뷰에 데이터 셋팅
        Post post = postList.get(position);

        holder.txtTitle.setText(post.title);
        holder.txtBody.setText(post.body);

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        TextView txtTitle;
        TextView txtBody;


        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            txtTitle = itemView.findViewById(R.id.txtTitle);
            txtBody = itemView.findViewById(R.id.txtBody);

        }
    }
}

# PostAdapter

 

 

 

package com.mugoori.networkapp2.model;

public class Post {

    public int userId;
    public int id;
    public String title;
    public String body;

    public Post() {

    }

    public Post(int userId, int id, String title, String body) {
        this.userId = userId;
        this.id = id;
        this.title = title;
        this.body = body;
    }
}

# Post