RecycleView的基本使用

RecycleView的使用

RecyclerView是Google在API 21下support.V7包里的控件,用来替代ListView。
官网对RecycleView的描述为：A flexible view for providing a limited window into a large data set。

一、使用RecycleView的前提条件

想使用RecycleView，一定要在build.gradle中引入compile 'com.android.support:recyclerview-v7:24.0.0'依赖。

二、使用RecycleView的优缺点

优点：

• RecycleView强制封装ViewHolder
• 相当轻松的设置布局管理器以控制Item的布局方式，横向、竖向以及瀑布流方式
• 可设置Item操作的动画，删除或者添加等
• 通过ItemDecoration，控制Item间的间隔，可自己绘制

缺点：

• 需要自己实现OnItemClickListener点击事件（这么实用的需求，Google竟然让我们自己实现...）

三、RecycleView的具体实现

先来看下效果图：

image1
image2
image3

使用方法如下：

1. 在xml布局里面直接添加RecycleView控件（跟ListView差不多），在布局中我添加了一个Spinner按钮来选择不同的Item展示模式，两个Button按钮用来添加或者删除Item。

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.furui.testrecycleview.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycleview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="50dp" />

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="170dp"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"></Spinner>

    <Button
        android:id="@+id/b1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_toRightOf="@+id/spinner"
        android:text="add" />

    <Button
        android:id="@+id/b2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_toRightOf="@+id/b1"
        android:text="delete" />
</RelativeLayout>

2. Activity界面分析

• 1 先找到RecycleView控件，然后设置一个默认的Item显示模式，并将自己封装的Adapter和RecycleView绑定

mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
mLinearLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
myRecycleViewAdapter = new MyRecycleViewAdapter(datas);
mRecyclerView.setAdapter(myRecycleViewAdapter);

• 2 设置item的点击事件，并设置点击Item时的动画效果

//设置item的点击事件
      myRecycleViewAdapter.setOnItemClickListener(new MyRecycleViewAdapter.OnItemClickListener() {
          @TargetApi(Build.VERSION_CODES.LOLLIPOP)
          @Override
          public void onItemClick(final View view, int position) {
              //设置点击动画
              view.animate()
                      .translationZ(15f)
                      .setDuration(300)
                      .setListener(new AnimatorListenerAdapter() {
                          @Override
                          public void onAnimationEnd(Animator animation) {
                              super.onAnimationEnd(animation);
                              view.animate()
                                      .translationZ(1f)
                                      .setDuration(500)
                                      .start();
                          }
                      }).start();
          }
      });

• 3 根据Spinner的选择，Item转换展示效果

mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
  @Override
  public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
      if (position == 0){
          mRecyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
      }else if (position == 1){
          mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
      }else if (position == 2)
          mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
}

下面是完整的Activity的代码：

package com.furui.testrecycleview;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.os.Build;
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.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
  private RecyclerView mRecyclerView;
  private MyRecycleViewAdapter myRecycleViewAdapter;
  private List<String> datas = new ArrayList<>();
  private LinearLayoutManager mLinearLayoutManager;
  private Spinner mSpinner;
  private static final String[] m={"竖着的RecycleView","GridView类型的RecycleView","瀑布流"};
  private ArrayAdapter<String> adapter;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
      Button add = (Button) findViewById(R.id.b1);
      Button delete = (Button) findViewById(R.id.b2);
      add.setOnClickListener(this);
      delete.setOnClickListener(this);
      mSpinner = (Spinner) findViewById(R.id.spinner);

      //将可选内容与ArrayAdapter连接起来
      adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,m);
      //设置下拉列表的风格
      adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

      //将adapter 添加到spinner中
      mSpinner.setAdapter(adapter);
      //设置默认值
      mSpinner.setVisibility(View.VISIBLE);
      mLinearLayoutManager = new LinearLayoutManager(this);
      mRecyclerView.setLayoutManager(mLinearLayoutManager);
      // do not change the size of the RecyclerView
      mRecyclerView.setHasFixedSize(true);
      mRecyclerView.setItemAnimator(new DefaultItemAnimator());
      mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
          @Override
          public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
              if (position == 0){
                  mRecyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
              }else if (position == 1){
                  mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));
              }else if (position == 2)
                  mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL));
          }
          @Override
          public void onNothingSelected(AdapterView<?> adapterView) {
          }
      });
      for (int i = 0; i < 3 ; i++) {
          datas.add("TestMyItem");
      }
      myRecycleViewAdapter = new MyRecycleViewAdapter(datas);
      mRecyclerView.setAdapter(myRecycleViewAdapter);
      //设置item的点击事件
      myRecycleViewAdapter.setOnItemClickListener(new MyRecycleViewAdapter.OnItemClickListener() {
          @TargetApi(Build.VERSION_CODES.LOLLIPOP)
          @Override
          public void onItemClick(final View view, int position) {
              //设置点击动画
              view.animate()
                      .translationZ(15f)
                      .setDuration(300)
                      .setListener(new AnimatorListenerAdapter() {
                          @Override
                          public void onAnimationEnd(Animator animation) {
                              super.onAnimationEnd(animation);
                              view.animate()
                                      .translationZ(1f)
                                      .setDuration(500)
                                      .start();
                          }
                      }).start();
          }
      });
  }
  public void  add(View view){
      datas.add("TestMyItem");
      int position  = datas.size();
      if (position > 0){
          myRecycleViewAdapter.notifyDataSetChanged();
      }
  }
  public void  delete(View view){
      int position  = datas.size();
      if (position >  0){
          datas.remove(position - 1);
          myRecycleViewAdapter.notifyDataSetChanged();
      }
  }

  @Override
  public void onClick(View view) {
      switch (view.getId()){
          case R.id.b1 :
              add(view);
              break;
          case R.id.b2 :
              delete(view);
              break;
      }
  }
}

3. RecycleView的Adapter和ListView的Adapter还是有点区别，来看看RecycleView的Adapter

package com.furui.testrecycleview;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
/**
 * Created by Administrator on 2016/11/2.
 */
public class MyRecycleViewAdapter extends RecyclerView.Adapter<MyRecycleViewAdapter.ViewHolder> {
    private List<String> mData;
    public MyRecycleViewAdapter(List<String> data) {
        mData = data ;
    }
    public OnItemClickListener itemClickListener;
    public  void setOnItemClickListener(OnItemClickListener itemClickListener){
        this.itemClickListener = itemClickListener;
    }
    public interface OnItemClickListener{
        void onItemClick(View view, int position);
    }
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_view, parent, false);
        return new ViewHolder(view);
    }
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.textView.setText(mData.get(position)+ position);
    }
    @Override
    public int getItemCount() {
        return mData.size();
    }
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        public TextView textView ;
        public ViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView;
            textView.setOnClickListener(this);
        }
        @Override
        public void onClick(View view) {
            if (itemClickListener != null){
                itemClickListener.onItemClick(view,getPosition());
            }
        }
    }
}