RecyclerView的那点事儿

RecyclerView

控件简介

ListView的升级版

LinearLayoutManager

GridLayoutManager

StaggeredGridLayoutManager

定制Item动画，指定Item之间的分隔线

RecyclerView相关的重要类

Adapter

ViewHolder

LayoutManager

ItemDecoration

ItemAnimator

添加RecyclerView控件依赖包

Android Studio开发工具，在本项目的build.gradle文件中添加

compile 'com.android.support:recyclerview-v7:23.1.1'

如果是eclipse的话，下载jar包，放到lib下，一般都会自动的build path,检查下即可。

如何下载jar ?

在SDK Manager中下载Support Library



sdk\extras\android\support\v7\recyclerview\libs

为Recycler准备数据

package demo.turing.com.materialdesignwidget.recyclerView;

import java.util.ArrayList;

import demo.turing.com.materialdesignwidget.recyclerView.model.SampleModel;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-30  20:21.
* @version 1.0
* @desc
*/
public class SimulatorData {

public static ArrayList<SampleModel> getSampleModelData(int size) {

ArrayList<SampleModel> sampleData = new ArrayList<SampleModel>(size);

for (int i = 0; i < size; i++) {
sampleData.add(new SampleModel("新的列表项< " + i + " >"));
}

return sampleData;
}

}

package demo.turing.com.materialdesignwidget.recyclerView.model;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-30  20:23.
* @version 1.0
* 对应Item中药显示的数据项
*/
public class SampleModel {

private String text;

public SampleModel(String text) {
this.text = text;
}

public String getText() {
return text;
}

public void setText(String text) {
this.text = text;
}
}

绘制列表项之间的分隔线

package demo.turing.com.materialdesignwidget.recyclerView;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-30  20:37.
* @version 1.0
*          分隔条
*
*
*   DividerItemDecoration  https://gist.github.com/alexfu/0f464fc3742f134ccd1e */
public class DividerItemDecoration extends RecyclerView.ItemDecoration {

// 默认分隔条Drawable资源的ID,使用系统自带的
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

private Drawable mDivider;

private int mOrientation;

public DividerItemDecoration(Context context, int orientation) {
// 使用TypedArray装载定义的ATTRS
final TypedArray a = context.obtainStyledAttributes(ATTRS);
// 获取系统提供的分隔条Drawable对象
mDivider = a.getDrawable(0);
// 回收TypedArray所占用的空间
a.recycle();
setOrientation(orientation);
}

/**
* 设置item的显示 水平 or 垂直
*
* @param orientation
*/
public void setOrientation(int orientation) {
if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
throw new IllegalArgumentException("invalid orientation");
}
mOrientation = orientation;
}

@Override
public void onDraw(Canvas c, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}

public void drawVertical(Canvas c, RecyclerView parent) {
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();

final int childCount = parent.getChildCount();

for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
RecyclerView v = new android.support.v7.widget.RecyclerView(
parent.getContext());
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
.getLayoutParams();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}

public void drawHorizontal(Canvas c, RecyclerView parent) {
final int top = parent.getPaddingTop();
final int bottom = parent.getHeight() - parent.getPaddingBottom();

final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
.getLayoutParams();
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}

@Override
public void getItemOffsets(Rect outRect, int itemPosition,
RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
}
}

}

实现Adapter

package demo.turing.com.materialdesignwidget.recyclerView.adapter;

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.ArrayList;
import java.util.Random;

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.SimulatorData;
import demo.turing.com.materialdesignwidget.recyclerView.model.SampleModel;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-30  21:03.
* @version 1.0
* @desc
*/
public class SampleRecyclerAdapter extends RecyclerView.Adapter<SampleRecyclerAdapter.ViewHolder> {

// 模拟数据
private  ArrayList<SampleModel> sampleData = SimulatorData.getSampleModelData(20);

/**
* 用于创建控件
*
* @param parent
* @param viewType
* @return
*/
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

// 获得列表项控件（LinearLayer对象）

// list_basic_item.xml布局文件中只包含一个<LinearLayer>标签，
// 在该标签中包含了一个<TextView>标签, item是LinearLayout对象
View item = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list_basic_item, parent, false);

ViewHolder viewHolder = new ViewHolder(item);

return viewHolder;
}

/**
* 为控件设置数据
*
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(ViewHolder holder, int position) {

//  获取当前item中显示的数据
final SampleModel rowData = sampleData.get(position);

//  设置要显示的数据
holder.textViewSample.setText(rowData.getText());
// 设置tag
holder.itemView.setTag(rowData);

}

@Override
public int getItemCount() {
return sampleData.size();
}

/**
* 删除指定的Item
*
* @param position
*/
public void removeData(int position) {
sampleData.remove(position);
//  通知RecyclerView控件某个Item已经被删除
notifyItemRemoved(position);

}

/**
* 在指定位置添加一个新的Item
*
* @param positionToAdd
*/
public void addItem(int positionToAdd) {
sampleData.add(positionToAdd, new SampleModel("新的列表项" + new Random().nextInt(10000)));
//  通知RecyclerView控件插入了某个Item
notifyItemInserted(positionToAdd);
}

/**
* 对应Item中的控件
*/
public static class ViewHolder extends RecyclerView.ViewHolder {

private final TextView textViewSample;

public ViewHolder(View itemView) {
super(itemView);
textViewSample = (TextView) itemView
.findViewById(R.id.textViewSample);
}
}

}

完成使用RecyclerView控件的最后工作

package demo.turing.com.materialdesignwidget.recyclerView;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.adapter.SampleRecyclerAdapter;

public class RecyclerViewAct extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_view);

// 获取RecyclerView对象
RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view);

//  创建线性布局管理器（默认是垂直方向）
LinearLayoutManager layoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);

//  为RecyclerView指定布局管理对象
recyclerView.setLayoutManager(layoutManager);

//  创建列表项分隔线对象
RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST);

//  为RecyclerView控件指定分隔线对象
recyclerView.addItemDecoration(itemDecoration);

SampleRecyclerAdapter sampleRecyclerAdapter = new SampleRecyclerAdapter();
recyclerView.setAdapter(sampleRecyclerAdapter);

}

}

效果图

定制个性化分隔条

drawable\divider_custom.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">

<size android:height="4dp"></size>
<!--渐变色-->
<gradient
android:centerColor="#ff0000ff"
android:endColor="#ffff0000"
android:startColor="#ffff0000"
android:type="linear"></gradient>

</shape>

主题中设置

<item name="android:listDivider">@drawable/divider_custom</item>

瀑布流

StaggeredGridLayuoutAct.java

package demo.turing.com.materialdesignwidget.recyclerView;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;

import java.util.List;

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.adapter.StaggeredGridLayoutAdapter;
import demo.turing.com.materialdesignwidget.recyclerView.model.SampleModel;

/**
* 不采用分隔线， 在Item的布局中 采用layout_margin的方式
*
* 主要是动态设置View的高度 adapter类中的 onBindViewHolder
*/

public class StaggeredGridLayuoutAct extends AppCompatActivity {

private RecyclerView recyclerView ;

// 模拟数据
private List<SampleModel> sampleData = SimulatorData.getSampleModelData(20);

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_staggered_grid_layuout);

// 查找组件
recyclerView = (RecyclerView) findViewById(R.id.id_rv_staggered);

// 创建布局管理器  -3列，垂直
StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);
// 设置布局
recyclerView.setLayoutManager(manager);

// Adapter
StaggeredGridLayoutAdapter adapter = new StaggeredGridLayoutAdapter(this,sampleData);
recyclerView.setAdapter(adapter);

}
}

activity_staggered_grid_layuout.xml

<?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="demo.turing.com.materialdesignwidget.recyclerView.StaggeredGridLayuoutAct">

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

</RelativeLayout>

StaggeredGridLayoutAdapter.java

package demo.turing.com.materialdesignwidget.recyclerView.adapter;

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.TextView;

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

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.model.SampleModel;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-31  20:19.
* @version 1.0
* @desc
*/
public class StaggeredGridLayoutAdapter extends RecyclerView.Adapter<StaggeredGridLayoutAdapter.ViewHolder> {

private Context context;
private List<SampleModel> datas;
private LayoutInflater inflater;
// 随机高度的结合
private List<Integer> mHeights;

/**
* 构造函数
*
* @param context
* @param datas
*/
public StaggeredGridLayoutAdapter(Context context, List<SampleModel> datas) {
this.context = context;
this.datas = datas;
this.inflater = LayoutInflater.from(context);

// 初始化随机高度的集合
mHeights = new ArrayList<>();
for (int i = 0; i < datas.size(); i++) {
mHeights.add((int)(100 + Math.random() * 300));
}
}

@Override
public StaggeredGridLayoutAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// 动态加载Item的布局文件
View view = inflater.inflate(R.layout.list_basic_item, parent, false);
// 实例化ViewHolder
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}

@Override
public void onBindViewHolder(StaggeredGridLayoutAdapter.ViewHolder holder, int position) {

// 获取当前Item中的显示的数据
SampleModel sampleModel = datas.get(position);

//设置控件的随机高度
ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
lp.height = mHeights.get(position);
holder.itemView.setLayoutParams(lp);

// 设置组件的值
holder.textView.setText(sampleModel.getText());
// 设置tag
holder.itemView.setTag(sampleModel);

}

@Override
public int getItemCount() {
return datas.size();
}

/**
* ViewHoder
*/
class ViewHolder extends RecyclerView.ViewHolder {

TextView textView;

public ViewHolder(View itemView) {
super(itemView);
textView = (TextView) itemView
.findViewById(R.id.textViewSample);
}
}
}

list_basic_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="3dp"
android:background="#6495ED"
android:gravity="center"
android:orientation="horizontal">

<TextView
android:id="@+id/textViewSample"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="演示"/>

</RelativeLayout>

效果图

动画效果

// 默认动画效果
recyclerView.setItemAnimator(new DefaultItemAnimator());

notifyItemRemoved(position)

/**
* 删除指定的Item
*
* @param position
*/
public void removeData(int position) {
sampleData.remove(position);
//  通知RecyclerView控件某个Item已经被删除
notifyItemRemoved(position);

}

notifyItemInserted(positionToAdd)

/**
* 在指定位置添加一个新的Item
*
* @param positionToAdd
*/
public void addItem(int positionToAdd) {
sampleData.add(positionToAdd, new SampleModel("新的列表项" + new Random().nextInt(10000)));
//  通知RecyclerView控件插入了某个Item
notifyItemInserted(positionToAdd);
}

为RecyclerView添加item的点击事件

方法一：利用回调的方式实现(不太完善，仍可实现)

实现步骤如下：

在adapter类中，定义接口，接口中定义两个方法分别对应click和longClick，定义完接口，添加接口和设置Adapter接口的方法：

/**
* 接口 ，提供两个方法
*/
public interface OnRecyclerViewItemClickListener{
// 单击事件
void onItemClick(View view ,int position);
// 长按触发的事件
void onItemLongClick(View view ,int position);
}
// 定义OnRecyclerViewItemClickListener对象
public OnRecyclerViewItemClickListener  mOnRecyclerViewItemClickListener ;

// 暴漏给外部的set方法，持有OnRecyclerViewItemClickListener对象
public void setOnRecyclerViewItemClickListener(OnRecyclerViewItemClickListener listener){
this.mOnRecyclerViewItemClickListener = listener ;
}

在onBindViewHolder方法中

// 点击事件
if(mOnRecyclerViewItemClickListener != null){
// click
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mOnRecyclerViewItemClickListener.onItemClick(holder.itemView,position);
}
});
// longClick
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
mOnRecyclerViewItemClickListener.onItemLongClick(holder.itemView,position);
return false;
}
});

}

做完这些事情，我们就可以在Activity或其他地方为RecyclerView添加项目点击事件了，

// 设置监事件
sampleRecyclerAdapter.setOnRecyclerViewItemClickListener(new SampleRecyclerAdapter.OnRecyclerViewItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(RecyclerViewAct.this,"Click" + position ,Toast.LENGTH_SHORT).show();
}

@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(RecyclerViewAct.this,"LongClick" + position ,Toast.LENGTH_SHORT).show();

}
});

完整代码如下：

RecyclerViewAct

package demo.turing.com.materialdesignwidget.recyclerView;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Toast;

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.adapter.SampleRecyclerAdapter;

public class RecyclerViewAct extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_view);

// 获取RecyclerView对象
RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view);

//  创建线性布局管理器（默认是垂直方向）
LinearLayoutManager layoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);

//  为RecyclerView指定布局管理对象
recyclerView.setLayoutManager(layoutManager);

//  创建列表项分隔线对象
RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST);

//  为RecyclerView控件指定分隔线对象
recyclerView.addItemDecoration(itemDecoration);

// 默认动画效果
recyclerView.setItemAnimator(new DefaultItemAnimator());

SampleRecyclerAdapter sampleRecyclerAdapter = new SampleRecyclerAdapter();
recyclerView.setAdapter(sampleRecyclerAdapter);

// 设置监事件
sampleRecyclerAdapter.setOnRecyclerViewItemClickListener(new SampleRecyclerAdapter.OnRecyclerViewItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(RecyclerViewAct.this,"Click" + position ,Toast.LENGTH_SHORT).show();
}

@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(RecyclerViewAct.this,"LongClick" + position ,Toast.LENGTH_SHORT).show();

}
});
}

}

SampleRecyclerAdapter

package demo.turing.com.materialdesignwidget.recyclerView.adapter;

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.ArrayList;
import java.util.Random;

import demo.turing.com.materialdesignwidget.R;
import demo.turing.com.materialdesignwidget.recyclerView.SimulatorData;
import demo.turing.com.materialdesignwidget.recyclerView.model.SampleModel;

/**
* MyApp
*
* @author Mr.Yang on 2016-03-30  21:03.
* @version 1.0
* @desc
*
*
* RecyclerView  点击事件 请看http://jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/1118/2004.html
*/
public class SampleRecyclerAdapter extends RecyclerView.Adapter<SampleRecyclerAdapter.ViewHolder> {

// 模拟数据
private  ArrayList<SampleModel> sampleData = SimulatorData.getSampleModelData(20);

/**
* 接口 ，提供两个方法
*/
public interface OnRecyclerViewItemClickListener{
// 单击事件
void onItemClick(View view ,int position);
// 长按触发的事件
void onItemLongClick(View view ,int position);
}
// 定义OnRecyclerViewItemClickListener对象
public OnRecyclerViewItemClickListener  mOnRecyclerViewItemClickListener ;

// 暴漏给外部的set方法，持有OnRecyclerViewItemClickListener对象
public void setOnRecyclerViewItemClickListener(OnRecyclerViewItemClickListener listener){
this.mOnRecyclerViewItemClickListener = listener ;
}

/**
* 用于创建控件
*
* @param parent
* @param viewType
* @return
*/
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

// 获得列表项控件（LinearLayer对象）

// list_basic_item.xml布局文件中只包含一个<LinearLayer>标签，
// 在该标签中包含了一个<TextView>标签, item是LinearLayout对象
View item = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list_basic_item, parent, false);

ViewHolder viewHolder = new ViewHolder(item);

return viewHolder;
}

/**
* 为控件设置数据
*
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {

//  获取当前item中显示的数据
final SampleModel rowData = sampleData.get(position);

//  设置要显示的数据
holder.textViewSample.setText(rowData.getText());
// 设置tag
holder.itemView.setTag(rowData);

// 点击事件
if(mOnRecyclerViewItemClickListener != null){
// click
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 通过getLayoutPosition，防止position错位
int layoutPosition = holder.getLayoutPosition();
mOnRecyclerViewItemClickListener.onItemClick(holder.itemView,layoutPosition);
}
});
// longClick
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
int layoutPosition = holder.getLayoutPosition();
mOnRecyclerViewItemClickListener.onItemLongClick(holder.itemView,layoutPosition);
return false;
}
});
}
}

@Override
public int getItemCount() {
return sampleData.size();
}

/**
* 删除指定的Item
*
* @param position
*/
public void removeData(int position) {
sampleData.remove(position);
//  通知RecyclerView控件某个Item已经被删除
notifyItemRemoved(position);

}

/**
* 在指定位置添加一个新的Item
*
* @param positionToAdd
*/
public void addItem(int positionToAdd) {
sampleData.add(positionToAdd, new SampleModel("新的列表项" + new Random().nextInt(10000)));
//  通知RecyclerView控件插入了某个Item
notifyItemInserted(positionToAdd);
}

/**
* 对应Item中的控件
*/
public static class ViewHolder extends RecyclerView.ViewHolder {

private final TextView textViewSample;

public ViewHolder(View itemView) {
super(itemView);
textViewSample = (TextView) itemView
.findViewById(R.id.textViewSample);
}
}

}

方法二：使用观察者模式实现

原理：

为RecyclerView的每个子item设置setOnClickListener，然后在onClick中再调用一次对外封装的接口，将这个事件传递给外面的调用者。而“为RecyclerView的每个子item设置setOnClickListener”在Adapter中设置。其实直接在onClick中也能完全处理item的点击事件，但是这样会破坏代码的逻辑。

步骤

在自定义的adapter（记得implements View.OnClickListener，下面有个onClick方法）中定义如下接口,模拟ListView的OnItemClickListener：

//define interface
public static interface OnRecyclerViewItemClickListener {
void onItemClick(View view , String data);
}

声明一个这个接口的变量：

private OnRecyclerViewItemClickListener mOnItemClickListener = null;

在onCreateViewHolder()中为每个item添加点击事件：

@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup,  int viewType) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item, viewGroup, false);
ViewHolder vh = new ViewHolder(view);
//将创建的View注册点击事件
view.setOnClickListener(this);
return vh;
}

将点击事件转移给外面的调用者：

@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
//注意这里使用getTag方法获取数据
mOnItemClickListener.onItemClick(v,(String)v.getTag());
}
}

意上面调用接口的onItemClick()中的v.getTag()方法，这需要在onBindViewHolder()方法中设置和item相关的数据

@Override
public void onBindViewHolder(ViewHolder viewHolder,  int position) {
viewHolder.mTextView.setText(datas[position]);
//将数据保存在itemView的Tag中，以便点击时进行获取
viewHolder.itemView.setTag(datas[position]);
}

最后暴露给外面的调用者，定义一个设置Listener的方法（）：

public void setOnItemClickListener(OnRecyclerViewItemClickListener listener) {
this.mOnItemClickListener = listener;
}

以上所有步骤都发生在自定义的adapter中，典型的观察者模式，有点绕的地方在于，这里涉及到两个观察者模式的使用，view的setOnClickListener本来就是观察者模式，我们将这个观察者模式的事件监听传递给了我们自己的观察者模式。

在Activity中使用

mRecyclerView = (RecyclerView)findViewById(R.id.my_recycler_view);
//创建默认的线性LayoutManager
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
//如果可以确定每个item的高度是固定的，设置这个选项可以提高性能
mRecyclerView.setHasFixedSize(true);
//创建并设置Adapter
mAdapter = new MyAdapter(data);
mRecyclerView.setAdapter(mAdapter);
mAdapter.setOnItemClickListener(new OnRecyclerViewItemClickListener(){
@Override
public void onItemClick(View view , String data){
Toast.makeText(MainActivity.this, data, 600).show();
}
});

~

RecyclerView添加Header

。。。。。。