Android开发学习之RecyclerView

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1、在app/build.gradle中添加RecyclerView依赖

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

注意依赖版本号

2、布局文件activity_main.xml引入RecycleView

 <android.support.v7.widget.RecyclerView

         android:id="@+id/recycler_view"

         android:layout_width="match_parent"

         android:layout_height="match_parent"></android.support.v7.widget.RecyclerView>

3、泛型类型Fruit.java

 package com.example.lalala.recyclerviewdemo;

 public class Fruit {

     private String name;

     private int imageId;

     public Fruit(String name,int imageId){

         this.name = name;

         this.imageId = imageId;

     }

     public String getName() {

         return name;

     }

     public int getImageId() {

         return imageId;

     }

 }

4、布局fruit_item.xml

 <?xml version="1.0" encoding="utf-8"?>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:orientation="horizontal" android:layout_width="match_parent"

     android:layout_height="wrap_content">

     <ImageView

         android:id="@+id/fruit_image"

         android:layout_width="wrap_content"

         android:layout_height="wrap_content" />

     <TextView

         android:id="@+id/fruit_name"

         android:layout_width="wrap_content"

         android:layout_height="wrap_content"

         android:layout_gravity="center_vertical"

         android:layout_marginLeft="10dp"

         />

 </LinearLayout>

5、适配器FruitAdapter.java

 package com.example.lalala.recyclerviewdemo;

 import android.support.annotation.NonNull;

 import android.support.v7.widget.RecyclerView;

 import android.view.LayoutInflater;

 import android.view.View;

 import android.view.ViewGroup;

 import android.widget.ImageView;

 import android.widget.TextView;

 import java.util.List;

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

     //适配器保存的数据

     private List<Fruit> mFruitList;

     //view容器类，ViewHolder容纳view

     static class ViewHolder extends RecyclerView.ViewHolder{

         ImageView imageView;

         TextView textView;

         public ViewHolder(View view){

             super(view);

             imageView = (ImageView)view.findViewById(R.id.fruit_image);

             textView = (TextView)view.findViewById(R.id.fruit_name);

         }

     }

     //构造函数初始化适配器

     public FruitAdapter(List<Fruit> fruitList){

         mFruitList = fruitList;

     }

     //创建ViewHolder

     @NonNull

     @Override

     public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {

         View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.fruit_item,viewGroup,false);

         ViewHolder viewHolder = new ViewHolder(view);

         return viewHolder;

     }

     //绑定数据到ViewHolder

     @Override

     public void onBindViewHolder(@NonNull ViewHolder viewHolder, int i) {

         Fruit fruit = mFruitList.get(i);

         viewHolder.imageView.setImageResource(fruit.getImageId());

         viewHolder.textView.setText(fruit.getName());

     }

     //返回子项个数

     @Override

     public int getItemCount() {

         return mFruitList.size();

     }

 }

6、配置并使用RecyclerView

 package com.example.lalala.recyclerviewdemo;

 import android.support.v7.app.AppCompatActivity;

 import android.os.Bundle;

 import android.support.v7.widget.LinearLayoutManager;

 import android.support.v7.widget.RecyclerView;

 import java.util.ArrayList;

 import java.util.List;

 public class MainActivity extends AppCompatActivity {

     private List<Fruit> fruitList = new ArrayList<>();

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         initFruit();

         //使用RecyclerView

         RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view);

         //布局管理器

         LinearLayoutManager layoutManager = new LinearLayoutManager(this);

         recyclerView.setLayoutManager(layoutManager);

         FruitAdapter adapter = new FruitAdapter(fruitList);

         recyclerView.setAdapter(adapter);

     }

     private void initFruit(){

         for(int i=0;i<8;i++){

             Fruit apple = new Fruit("Apple",R.mipmap.ic_launcher);

             fruitList.add(apple);

             Fruit pear = new Fruit("Pear",R.mipmap.ic_launcher);

             fruitList.add(pear);

             Fruit banana = new Fruit("Banana",R.mipmap.ic_launcher);

             fruitList.add(banana);

         }

     }

 }