[移动开发]RecycleView创建步骤

1、导入依赖

根据：compileSdkVersion 31

implementation 'com.android.support:recyclerview-v7:31.1.0'

2、创建MainActivity,并在layout中的activity_main中布局RecycleView

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycle_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

3、创建页面的整体布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="10dp">

    <!--显示图片-->
    <ImageView
        android:id="@+id/img_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <!--显示名称-->
    <TextView
        android:id="@+id/img_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="10dp"/>

</LinearLayout>

4.创建Fruit实体类

public class Fruit {
    private String name;//水果名
    private int ImgId;//水果图片的资源ID

    public Fruit(String name, int imgId) {
        this.name = name;
        ImgId = imgId;
    }

    public String getName() {
        return name;
    }

    public int getImgId() {
        return ImgId;
    }
}

5.创建RecycleView的适配器

package com.example.recycleviewtest;

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

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

import java.util.List;

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

    private List<Fruit> mFruitList;

    //创建内部类接受控件
     static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView fruitImage;
        TextView fruitName;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            fruitImage = itemView.findViewById(R.id.img_view);
            fruitName = itemView.findViewById(R.id.img_name);
        }
    }

    /**
     * 构造函数，把要展示的数据源传递进来，并赋值给全局变量mFruitList
     * @param fruitlist
     */
    public FruitAdapter(List<Fruit> fruitlist){
         mFruitList = fruitlist;
    }

    /**
     * 创建ViewHolder实例
     * @param parent
     * @param viewType
     * @return
     */
    @NonNull
    @Override
    public FruitAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        //加载fruit_item布局
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item,parent,false);
        //将加载出来的布局传入构造函数
        ViewHolder holder = new ViewHolder(view);
        //返回ViewHoder的实例
        return holder;
    }

    /**
     * 对RecycleView子项的数据进行赋值，会在每个子项被滚动到屏幕内的时候执行
     * @param holder
     * @param position
     */
    @Override
    public void onBindViewHolder(@NonNull FruitAdapter.ViewHolder holder, int position) {
        //通过position参数得到当前项的Fruit实例
        Fruit fruit = mFruitList.get(position);
        //讲数据设置到ViewHolder的ImageView和TextView
        holder.fruitImage.setImageResource(fruit.getImgId());
        holder.fruitName.setText(fruit.getName());
    }

    /**
     * 告诉RecycleView一共有多少子项，直接返回数据源的长度
     * @return
     */
    @Override
    public int getItemCount() {
        return mFruitList.size();
    }

}

6、开始使用RecycleView，修改MainActivity中的代码

package com.example.recycleviewtest;

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

import android.os.Bundle;

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

public class MainActivity extends AppCompatActivity {

    private List<Fruit> list = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //初始化数据
        initFruit();
        //获取RecycleView的实例
        RecyclerView recyclerView = findViewById(R.id.recycle_view);
        //创建LinearLayout-Manager对象，并将其设置到RecycleView中
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        //创建FruitAdapter的实例，并将水果数据传入到FruitAdapter的构造函数中
        FruitAdapter adapter = new FruitAdapter(list);
        recyclerView.setAdapter(adapter);
    }

    /*{"apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","cherry","Mongo",
            "apple","Banana","Orange","Watermelon","Pear","Grape","Pineapple","Strawberry","cherry","Mongo"};*/
    private void initFruit() {
        for (int i=0;i<2;i++) {
            Fruit apple = new Fruit("Apple",R.drawable.apple_pic);
            list.add(apple);
            Fruit banana = new Fruit("Banana",R.drawable.banana_pic);
            list.add(banana);
            Fruit orange = new Fruit("Orange",R.drawable.banana_pic);
            list.add(banana);
            Fruit watermelon = new Fruit("Watermelon",R.drawable.banana_pic);
            list.add(banana);
            Fruit pear = new Fruit("Pear",R.drawable.banana_pic);
            list.add(banana);
            Fruit grape = new Fruit("Grape",R.drawable.banana_pic);
            list.add(banana);
            Fruit pineapple = new Fruit("Pineapple",R.drawable.banana_pic);
            list.add(banana);
            Fruit strawberry = new Fruit("Strawberry",R.drawable.banana_pic);
            list.add(banana);
            Fruit cherry = new Fruit("Cherry",R.drawable.banana_pic);
            list.add(banana);
            Fruit mongo = new Fruit("Mongo",R.drawable.banana_pic);
            list.add(banana);
        }
    }
}
参考书籍：《第一行代码（第2版）》