【Android Studio】RecyclerView的使用

Java

Furit.java

package com.example.myapplication;

public class Fruit {
    private int imageId;
    private String name;



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

    public int getImageId() {
        return imageId;
    }

    public String getName() {
        return name;
    }
}

FruitAdapter.java

package com.example.myapplication;

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

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

import java.util.List;

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

    private List<Fruit> mFruitList;
    static class ViewHolder extends RecyclerView.ViewHolder{
        View fruitView;
        ImageView fruitImage;
        TextView fruitName;
        public ViewHolder(View view){
            //将子项的实例布局获取
            super(view);
            fruitView=view;//创建最外层的布局实例
            fruitImage=view.findViewById(R.id.fruit_image);
            fruitName=view.findViewById(R.id.fruit_name);
        }
    }
    public FruitAdapter(List<Fruit> fruitList){
        //获取数据源
        mFruitList=fruitList;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext())
                .inflate(R.layout.fruit_item,parent,false);//将布局加载进来
        ViewHolder holder=new ViewHolder(view);//将布局加载进入构造函数中
        //给每一个子项都添加一个点击事件监听器，
        //当有点击事件发生时，就获取当前子项返回，然后通过mFruitList获取相关信息
        holder.fruitView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position=holder.getAdapterPosition();
                Fruit fruit=mFruitList.get(position);
                Toast.makeText(v.getContext(),"I see you,"+fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        holder.fruitImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position=holder.getAdapterPosition();
                Fruit fruit=mFruitList.get(position);
                Toast.makeText(v.getContext(),fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        //获取当前的子项实例，并修改样式
        Fruit fruit=mFruitList.get(position);
        holder.fruitImage.setImageResource(fruit.getImageId());
        holder.fruitName.setText(fruit.getName());
    }

    @Override
    public int getItemCount() {
        //返回数据源的长度
        return mFruitList.size();
    }
}

MainActivity.java

package com.example.myapplication;

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

import android.os.Bundle;

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

public class MainActivity extends AppCompatActivity {
    private String[] data={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r"};
    private List<Fruit> fruitList=new ArrayList<Fruit>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
        RecyclerView recyclerView=findViewById(R.id.recyclerView);//创建RecyclerView实例
        //用于指定布局方式并加载，这里使用的是瀑布流网格布局
        StaggeredGridLayoutManager layoutManager=
                new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);//设置为3个为一组，纵向排列
        recyclerView.setLayoutManager(layoutManager);

        FruitAdapter fruitAdapter=new FruitAdapter(fruitList);//创建适配器
        recyclerView.setAdapter(fruitAdapter);//加载适配器
    }
    private void init(){
        //建立Fruit实例并装入fruitList中
        for(int i=0;i<2;i++){
            Fruit a=new Fruit(data[0]+"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", R.mipmap.ic_launcher);
            fruitList.add(a);
            Fruit b=new Fruit(data[1], R.mipmap.ic_launcher);
            fruitList.add(b);
            Fruit c=new Fruit(data[2], R.mipmap.ic_launcher);
            fruitList.add(c);
            Fruit d=new Fruit(data[3], R.mipmap.ic_launcher);
            fruitList.add(d);
            Fruit e=new Fruit(data[4], R.mipmap.ic_launcher);
            fruitList.add(e);
            Fruit f=new Fruit(data[5], R.mipmap.ic_launcher);
            fruitList.add(f);
            Fruit g=new Fruit(data[6], R.mipmap.ic_launcher);
            fruitList.add(g);
            Fruit h=new Fruit(data[7], R.mipmap.ic_launcher);
            fruitList.add(h);
            Fruit l=new Fruit(data[8], R.mipmap.ic_launcher);
            fruitList.add(l);
            Fruit j=new Fruit(data[9], R.mipmap.ic_launcher);
            fruitList.add(j);
        }
    }
}

layout

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="match_parent"
    tools:context=".MainActivity">

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


</LinearLayout>

fruit.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:orientation="vertical"
    android:layout_margin="5dp">

    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:layout_gravity="center_horizontal"/>

    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
        android:layout_marginTop="10dp"/>
</LinearLayout>