JAVA 파일

User.java

package com.com.recyclerview.user;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@AllArgsConstructor
@NoArgsConstructor
@Data
public class User {

    private String nation;
    private String rank;
    private String medals;
    private String records;
}

UserProvider.java

package com.com.recyclerview.provider;

import com.com.recyclerview.user.User;

import java.util.ArrayList;
import java.util.List;

public class UserProvider {

    public List<User> findAll(){
        List<User> users = new ArrayList<>();
        for (int i = 1; i <= 50; i++) {
            users.add(new User("국가" + i, i + "위", i + "개", "기록 없음"));
        }
        return users;
    }
}

UserAdapter.java

package com.com.recyclerview.adapter;

import android.content.Context;
import android.util.Log;
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.com.recyclerview.R;
import com.com.recyclerview.user.User;

import java.util.ArrayList;
import java.util.List;

// 2. 어댑터 만들기
public class UserAdapter extends RecyclerView.Adapter<UserAdapter.MyViewHolder> {
    private static final String TAG = "UserAdapter";
    private int createCount = 1;
    private int bindCount = 1;

    // 1. 뷰홀더 만들기
    public static class MyViewHolder extends RecyclerView.ViewHolder{
        private TextView tvNat, tvRank, tvMedal, tvRec;

        public MyViewHolder(View itemView) {
            super(itemView);
            tvNat = itemView.findViewById(R.id.tvNat);
            tvRank = itemView.findViewById(R.id.tvRank);
            tvMedal = itemView.findViewById(R.id.tvMedal);
            tvRec = itemView.findViewById(R.id.tvRec);
        }
        public void setItem(User user){
            tvNat.setText(user.getNation());
            tvRank.setText(user.getRank());
            tvMedal.setText(user.getMedals());
            tvRec.setText(user.getRecords());
        }
    }
    // 2. 어댑터 만들기 ( 이건 이 클래스 자체)

    // 3. 컬렉션 만들기
    private List<User> users = new ArrayList<>();

    // 4. 컬렉션 데이터 세팅
    public void addItems(List<User> users) {
        this.users = users;
        notifyDataSetChanged();
    }


    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Log.d(TAG, "onCreateViewHolder: 그림 생성" + createCount);
        createCount++;
        LayoutInflater layoutInflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = layoutInflater.inflate(R.layout.user_item, parent, false);
        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(UserAdapter.MyViewHolder holder, int position) {
        Log.d(TAG, "onBindViewHolder: 바인딩" + bindCount);
        bindCount++;
        User user = users.get(position);
        holder.setItem(user);
    }

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

MainActivity.java

package com.com.recyclerview;

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

import android.os.Bundle;

import com.com.recyclerview.adapter.UserAdapter;
import com.com.recyclerview.provider.UserProvider;

public class MainActivity extends AppCompatActivity {

    private RecyclerView rvUsers;
    private RecyclerView.LayoutManager layoutManager;
    private UserAdapter userAdapter;

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

        init();
        initAdapter();
        initData();
    }

    private void init(){
        rvUsers = findViewById(R.id.rvUsers);
    }
    private void initAdapter(){
        layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        rvUsers.setLayoutManager(layoutManager);
        userAdapter = new UserAdapter();
        rvUsers.setAdapter(userAdapter);
    }
    private void initData(){
        UserProvider userProvider = new UserProvider();
        userAdapter.addItems(userProvider.findAll());
    }

}

XML 파일

user_item.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="150dp"
    android:paddingStart="20dp"
    android:layout_marginBottom="10dp">

    <TextView
        android:id="@+id/tvNat"
        android:textSize="30dp"
        android:textStyle="bold"
        android:gravity="center_vertical"
        android:layout_weight="20"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="국가" />
    <TextView
        android:id="@+id/tvRank"
        android:textSize="18dp"
        android:textStyle="bold"
        android:gravity="center_vertical"
        android:layout_weight="10"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="순위" />
    <TextView
        android:id="@+id/tvMedal"
        android:textSize="18dp"
        android:textStyle="bold"
        android:gravity="center_vertical"
        android:layout_weight="10"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="메달 수" />
    <TextView
        android:id="@+id/tvRec"
        android:textSize="18dp"
        android:textStyle="bold"
        android:gravity="center_vertical"
        android:layout_weight="10"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="이전 기록" />
    <View
        android:layout_width="match_parent"
        android:layout_height="2dp"
        android:background="#CC3535"/>
        
</androidx.appcompat.widget.LinearLayoutCompat>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvUsers"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</androidx.appcompat.widget.LinearLayoutCompat>