RecyclerView的使用

文件：ReViewActivity.zip

一、导入RecyclerView依赖包

1.加入该包的名称，然后将sdk版本改成对应包的版本号，然后点击右上角的更新：

 implementation 'androidx.appcompat:appcompat:1.0.0'
 implementation 'androidx.recyclerview:recyclerview:1.0.0'

2.在activity_main中添加布局：

3.新建一个item_recycler_view.xml，为RecyclerView内的元素设定xml样式：

4.创建一个适配器的类RecyclerViewAdapterDemo：

（1）创建适配器类继承自RecyclerView.Adapter，泛型传入RecyclerView.ViewHolder类

（2）创建内部类的子类MyViewHolder，初始化控件

（3）重写RecyclerView.Adapter类的相关方法

5.在MainActivity中获取对象：

6.初始化数据：

7.适配器实例化：

8.设置LayoutManager（布局格式）：

9.设置Adapter，把适配器的数据传入recyclerView：

二、代码整合：

1.activity_main的xml布局格式recyclerview代码：

<?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/rv_demo"
      android:layout_width="match_parent"
      android:layout_height="match_parent">
  </androidx.recyclerview.widget.RecyclerView>
</LinearLayout>

2.item_recycler_view.xml的布局内容代码：

<?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="wrap_content"
    tools:context=".MainActivity">
  <TextView
      android:id="@+id/tv_test"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:gravity="center"
      android:text="测试"
      android:textSize="20sp"
      android:layout_marginRight="2dp"
      android:layout_marginLeft="2dp"
      android:layout_marginTop="2dp"
      android:layout_marginBottom="2dp"
      android:textColor="#E2583F"
      android:background="#7DAF45" />
</LinearLayout>

3.RecyclerViewAdapterDemo的适配器代码：

import android.content.Context;
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 java.util.List;
    // 1.创建适配器类继承自RecyclerView.Adapter，泛型传入RecyclerView.ViewHolder类
public class RecyclerViewAdapterDemo extends RecyclerView.Adapter
                                <RecyclerViewAdapterDemo.MyViewHolder> {
    private Context context;
    private List<String> list;
    private View inflater;
    public RecyclerViewAdapterDemo(Context context,List<String> list){
        this.context=context;
        this.list=list;
    }
    //3.重写RecyclerView.Adapter类的相关方法
    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        inflater= LayoutInflater.from(context).inflate(R.layout.item_recycler_view,parent,false);
        MyViewHolder viewHolder=new MyViewHolder(inflater);
        return viewHolder;
    }
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        holder.tv_view.setText(list.get(position));
    }
    @Override
    public int getItemCount() {
        return list.size();
    }
    // 2.创建内部类即RecyclerView.ViewHolder类的子类MyViewHolder，并初始化item的控件。
    class MyViewHolder extends RecyclerView.ViewHolder{
        private TextView tv_view;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            tv_view=itemView.findViewById(R.id.tv_view);
        }
    }
}

4.MainActivity的代码：

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Context;
import android.os.Bundle;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
    // 1.获取RecyclerView对象
    private RecyclerView recyclerView;
    private RecyclerViewAdapterDemo adapterDemo;
    private Context context;
    private List<String> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context=this;
        // 2.初始化数据
        recyclerView=findViewById(R.id.rv_demo);
        //3.适配器实例化
        list=new ArrayList<>();
        for (int i=0;i<10;i++){
            list.add("这是第"+i+"个测试");
        }
        adapterDemo=new RecyclerViewAdapterDemo(context,list);
       // 4.设置LayoutManager
       // GridLayoutManager manager=new GridLayoutManager(context,3);
       // manager.setOrientation(GridLayoutManager.VERTICAL);
       LinearLayoutManager manager=new LinearLayoutManager(context);
       manager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(manager);
        // 5. 设置Adapter
        recyclerView.setAdapter(adapterDemo);
    }
}

5.结果图：

6.设置LayoutManager不同，布局样式不同（ps：这个是GridManager的布局格式）：

三、RecyclerView的另外一些使用

mRecyclerView = findView(R.id.id_recyclerview);
//设置布局管理器
mRecyclerView.setLayoutManager(layout);
//设置adapter
mRecyclerView.setAdapter(adapter);
//设置Item增加、移除动画
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
//添加分割线
mRecyclerView.addItemDecoration(new DividerItemDecoration(
                getActivity(), DividerItemDecoration.HORIZONTAL_LIST));