Android RecyclerView控件的使用

                                                                             RecyclerView

简介：

1.RecylerView是 support-v7 中的一个控件

2.该控件用于在有限的窗口中展示大量数据集，例如：ListView、GridView。RecyclerView架构，提供了一种插拔式的体验，高度的解耦，异常的灵活，通过设置它提供的不同

LayoutManager，ItemDecoration , ItemAnimator实现令人瞠目的效果。

 你想要控制其显示的方式，请通过布局管理器LayoutManager  你想要控制Item间的间隔（可绘制），请通过ItemDecoration

你想要控制Item增删的动画，请通过ItemAnimator

 但是事件得自己写，官方没有响应的事件

3.使用：

1.导入依赖

compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'

2.布局文件

3.Activity中的代码

这里的数据是模拟的。

4.适配器

5.不同布局之间切换，只需要改变布局管理器即可

6.自定义点击事件

还是接口回调

//在Activity设置点击事件

//布局之间切换的效果如下图

完整代码:

--------------------MainActivity-------------------

package com.gjl.day06_recyclerview;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
   private int[] imgId = new int[]{
         R.drawable.aaaa,
         R.drawable.abc,
         R.drawable.b,
         R.drawable.c
   };
   private RecyclerView rv;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      //RcyclerView找到控件，设置适配器
      rv = (RecyclerView) findViewById(R.id.recyclerView);
      ArrayList<User> list = new ArrayList<>();
      //初始化数据
      for (int i = 0; i < 100; i++) {
         String conent = i + "林志玲";
         int img = imgId[i % imgId.length];
         User user = new User(img, conent);
         list.add(user);
      }
      //设置布局管理器
      rv.setLayoutManager(new LinearLayoutManager(MainActivity.this));
      //设置动画
      rv.setItemAnimator(new DefaultItemAnimator());
      //设置适配器
      final MyAdapter adapter = new MyAdapter(MainActivity.this, list);
      rv.setAdapter(adapter);
      //设置条目点击事件
      adapter.setOnMyItemClickListener(new MyAdapter.MyItemClick() {
         @Override
         public void itemClick(View view, int postion) {
            Toast.makeText(MainActivity.this,"---"+postion,Toast.LENGTH_SHORT).show();
            User user = new User(R.mipmap.ic_launcher, "hello 机器人");
//          adapter.addUser(user,postion);
            adapter.removeUser(postion);
         }
      });
   }

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      getMenuInflater().inflate(R.menu.item, menu);
      return true;
   }

   @Override
   public boolean onOptionsItemSelected(MenuItem item) {
      int itemId = item.getItemId();
      switch (itemId) {
         case R.id.one:
            //listView
            rv.setLayoutManager(new LinearLayoutManager(MainActivity.this));
            break;
         case R.id.two:
            //gridview
            rv.setLayoutManager(new GridLayoutManager(MainActivity.this,2));
            break;
         case R.id.three:
                //流失布局
            rv.setLayoutManager(new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));
            break;
      }
      return super.onOptionsItemSelected(item);
   }
}

----------------MyAdapter------------------

package com.gjl.day06_recyclerview;

import android.content.Context;
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.ArrayList;


public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
   private  Context context;
   private  ArrayList<User> list;
   private MyItemClick myItemClick;//监听器
   
   public MyAdapter(Context context, ArrayList<User> list){
      this.context = context;
      this.list = list;
   }
   //创建ViewHolder的时候
   //实例化ViewHolder
   @Override
   public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
      //条目布局
      View view = LayoutInflater.from(context).inflate(R.layout.item, null);
      //实例化ViewHolder ,将布局传入
      MyViewHolder viewHolder = new MyViewHolder(view);
      return viewHolder; 
   }
   //当绑定ViewHolder的时候
   //给控件设置数据
   @Override
   public void onBindViewHolder(final MyViewHolder holder, final int position) {
      holder.getTextView().setText(list.get(position).getContent());
      holder.getImageView().setImageResource(list.get(position).getImageId());
      //设置点击事件
      if (myItemClick!=null){
         holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               //调用接口里面的方法
               myItemClick.itemClick(holder.itemView,position);
            }
         });
      }
   }
   //条目数量
   @Override
   public int getItemCount() {
      return list.size();
   }
   //定义接口，实现条目点击事件
   public interface MyItemClick{
      void itemClick(View view,int postion);
   }

   public void setOnMyItemClickListener(MyItemClick myItemClick){
      this.myItemClick = myItemClick;
   }
   //添加数据
   public void addUser(User user,int position){
      list.add(position,user);
      //更新适配器
      notifyItemInserted(position);//参数，位置，在那里插入了数据
   }

   //删除数据
   public void removeUser(int position){
      list.remove(position);
      //通知适配器
      notifyItemRemoved(position);
   }
   //ViewHolder
   class MyViewHolder extends RecyclerView.ViewHolder{
      private ImageView imageView;
      private TextView textView;
      public MyViewHolder(View itemView) {
         super(itemView);
         this.imageView = itemView.findViewById(R.id.image);
         this.textView = itemView.findViewById(R.id.content);
      }

      public ImageView getImageView() {
         return imageView;
      }

      public void setImageView(ImageView imageView) {
         this.imageView = imageView;
      }

      public TextView getTextView() {
         return textView;
      }

      public void setTextView(TextView textView) {
         this.textView = textView;
      }
   }

}

------------------User----------------

package com.gjl.day06_recyclerview;

public class User {
   private int imageId;
   private String content;

   public User(int imageId, String content) {
      this.imageId = imageId;
      this.content = content;
   }

   public User() {
   }

   public int getImageId() {
      return imageId;
   }

   public void setImageId(int imageId) {
      this.imageId = imageId;
   }

   public String getContent() {
      return content;
   }

   public void setContent(String content) {
      this.content = content;
   }
}

-------------------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"
    android:orientation="vertical"
    tools:context="com.gjl.day06_recyclerview.MainActivity">

   <android.support.v7.widget.RecyclerView
       android:id="@+id/recyclerView"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"></android.support.v7.widget.RecyclerView>

</LinearLayout>

------------------item.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:gravity="center"
              android:orientation="vertical">

    <ImageView
        android:scaleType="centerCrop"
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/aaaa"/>

    <TextView
        android:id="@+id/content"
        android:layout_width="wrap_content"
        android:layout_height="30dp"
        android:gravity="center"
        android:text="测试"
        android:textSize="30sp"/>
</LinearLayout>