[Android Studio] 안드로이드 스튜디오 Java Recycler View 만들기

1. Build.gradle 수정

implementation 'com.android.support:recyclerview-v7:28.0.0'

에러 등장

https://pasongsong.tistory.com/123

[Android Studio] Version 28 (intended for Android Pie and below) is the last version of the legacy support library, so we recomm

---

2. Item layout 구성

하나 만들어 줍니다.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/IV_food"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginBottom="5dp"
        app:layout_constraintBottom_toTopOf="@+id/BTN_insert_food"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        tools:srcCompat="@tools:sample/avatars" />

    <Button
        android:id="@+id/BTN_insert_food"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        tools:layout_editor_absoluteY="319dp" />
</androidx.constraintlayout.widget.ConstraintLayout>

---

3. Class 만들기

package com.example.k_food_application;

public class One_food {
    int food_resourceId;
    
    public One_food(int food_resourceId){
        this.food_resourceId = food_resourceId;
    }
    
    public int getFood_resourceId(){
        return food_resourceId;
    }
    
    public void setFood_resourceId(int food_resourceId){
        this.food_resourceId = food_resourceId;
    }
}

---

4. Adapter 구현

https://developer.android.com/guide/topics/ui/layout/recyclerview?hl=ko 

RecyclerView로 동적 목록 만들기  |  Android 개발자  |  Android Developers

package com.example.k_food_application;


import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

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

import java.util.ArrayList;

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

    private ArrayList<One_food> food_list;

    /**
     * Provide a reference to the type of views that you are using
     * (custom ViewHolder).
     */

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

    @Override
    public void onBindViewHolder(@NonNull DayMealAdapter.ViewHolder holder, int position) {
        holder.onBind(food_list.get(position));
    }

    public void setFoodList(ArrayList<One_food> list){
        this.food_list = list;
        notifyDataSetChanged();
    }


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

    class ViewHolder extends RecyclerView.ViewHolder {
        ImageView food_img;


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

            food_img = (ImageView) itemView.findViewById(R.id.IV_food);

        }

        void onBind(One_food item){
            food_img.setImageResource(item.getFood_resourceId());

        }
    }
    
}

5. Main 수정

//recycler View 연결
RecyclerView one_food = (RecyclerView) findViewById(R.id.Recyc_food);
DayMealAdapter one_food_Adapter = new DayMealAdapter();
one_food.setAdapter(one_food_Adapter);
one_food.setLayoutManager(new LinearLayoutManager(this));

ArrayList<One_food> meal_items = new ArrayList<>();
meal_items.add(new One_food(R.drawable.ic_camera));

one_food_Adapter.setFoodList(meal_items);