在网上看见有关RecyclerView的介绍，说是ListView的进阶版，官方推荐，便找来资料，耍耍。
首先挂上官方的教程，官方是最具权威和最让人信服的第一手资料。
https://developer.android.com/training/material/lists-cards.html
- To create complex lists and cards with material design styles in your apps, you can use the
RecyclerViewandCardViewwidgets.- 从这里我们能看出是为了 创建 material design styles 的风格，所以提供了 RecyclerView and CardView widgets.
- The
RecyclerViewwidget is a more advanced and flexible version ofListView. This widget is a container for displaying large data sets that can be scrolled very efficiently by maintaining a limited number of views. Use theRecyclerViewwidget when you have data collections whose elements change at runtime based on user action or network events.- 具体的没有太多感悟，不好乱写，总之比 ListView更加 先进和灵活。
- The
RecyclerViewclass simplifies the display and handling of large data sets by providing:- Layout managers for positioning items
- Default animations for common item operations, such as removal or addition of items
- RecyclerView这个类通过如下2种方式简化了显示和处理大量数据集。1:Layout managers 用来管理items的显示 2:默认的animation用来运行普通的item，例如 删除和添加 items。
- You also have the flexibility to define custom layout managers and animations for
RecyclerViewwidgets.- 说实话 不懂，是指自己定义自己的Recyclerview吗？从来没干过这等事。
说什么都不如图片来的形象。
还有源码就不写了，以后有空再来补补。
说完这等子事，来写写代码，官方给的源码自己看着写，能如大概的了解。
下面是我自己写的Demo，先下效果图。
第一次Gif图不太会截。第一张图是可以下拉的。
The activity_ main.xml Layout
就如ListView一样我们，我们需要先创建布局。这里的RecyclerView可以看作是容器。
需要我们先导入Jar包，
1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 xmlns:tools="http://schemas.android.com/tools" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 tools:context=".MainActivity"> 6 7 <android.support.v7.widget.RecyclerView 8 android:id="@+id/recyclerView" 9 android:scrollbars="vertical"10 android:layout_width="match_parent"11 android:layout_height="match_parent"12 android:background="#CCCC"/>13 14 </RelativeLayout>
Creating our data class
ColorDateItem.java1 package com.ryan.recyclerviewdemo01; 2 3 import android.graphics.Color; 4 5 /** 6 * Created by air on 15-8-17. 7 */ 8 public class ColorDateItem { 9 private String name;10 private int color;11 12 public ColorDateItem(String name, String color) {13 this.color = Color.parseColor((color));14 this.name = name;15 }16 17 public int getColor() {18 return color;19 }20 21 public String getName() {22 return name;23 }24 }
The data layout
这个布局是给ColorDataItem对象服务的。 就是我们我们想展示我们的数据到屏幕上的样子。
1 <?xml version="1.0" encoding="utf-8"?> 2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent"> 5 <View 6 android:layout_width="match_parent" 7 android:layout_height="150dp" 8 android:id="@+id/colorBlock" 9 android:background="#CCCCCC"/>10 11 <TextView12 android:layout_width="match_parent"13 android:layout_height="wrap_content"14 android:id="@+id/colorName"15 android:text="name"16 android:textColor="@android:color/white"17 android:textSize="22dp"18 android:layout_margin="10dp"/>19 20 </RelativeLayout>
Creating the Adapter
我们的adaper必须继承RecyclerView，并且必须复写3个方法。
onCreateViewHolder()
1 @Override2 public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {3 //create a new view4 View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout,null);5 //set the view's size , margins , padding and layout parameters6 //……7 MyViewHolder vh = new MyViewHolder(v);8 return vh;9 }
这里 Layoutflater ， inflate还不太会用
onBindVIewHolder()
1 @Override 2 public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { 3 // - get element from your dataset(数据集) at this position 4 // - replace the contents of the view with that element 5 ColorDateItem dateItem = dateItems.get(position); 6 /** casting the viewHolder to MyViewHolder so i could interface with the views */ 7 MyViewHolder myViewHolded = (MyViewHolder) holder; 8 myViewHolded.colorBlock.setBackgroundColor((dateItem.getColor())); 9 myViewHolded.colorName.setText(dateItem.getName());10 }
getItemCount()
1 @Override2 public int getItemCount() {3 return dateItems.size();4 }
MyViweHolder class
1 /** this is our ViewHolder class */ 2 public static class MyViewHolder extends RecyclerView.ViewHolder{ 3 public TextView colorName; 4 public View colorBlock; 5 6 public MyViewHolder(View itemView) { 7 super(itemView); /** Must call super()first */ 8 colorName = (TextView) itemView.findViewById(R.id.colorName); 9 colorBlock = itemView.findViewById(R.id.colorBlock);10 }11 }
总体效果
MyAdapter.class
1 package com.ryan.recyclerviewdemo01; 2 3 import android.support.v7.widget.RecyclerView; 4 import android.view.LayoutInflater; 5 import android.view.View; 6 import android.view.ViewGroup; 7 import android.widget.TextView; 8 9 import java.util.List;10 11 /**12 * Created by air on 15-8-17.13 */14 public class Myadapter extends RecyclerView.Adapter {15 16 private List<ColorDateItem> dateItems;17 18 public Myadapter(List<ColorDateItem> dateItems) {19 this.dateItems = dateItems;20 }21 22 23 24 /** this is our ViewHolder class */25 public static class MyViewHolder extends RecyclerView.ViewHolder{26 public TextView colorName;27 public View colorBlock;28 29 public MyViewHolder(View itemView) {30 super(itemView); /** Must call super()first */31 colorName = (TextView) itemView.findViewById(R.id.colorName);32 colorBlock = itemView.findViewById(R.id.colorBlock);33 }34 }35 36 37 38 //39 @Override40 public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {41 //create a new view42 View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout,null);43 //set the view's size , margins , padding and layout parameters44 //……45 MyViewHolder vh = new MyViewHolder(v);46 return vh;47 }48 49 50 //replace the contents of the view (invoked by the layout manager)51 @Override52 public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {53 // - get element from your dataset(数据集) at this position54 // - replace the contents of the view with that element55 ColorDateItem dateItem = dateItems.get(position);56 /** casting the viewHolder to MyViewHolder so i could interface with the views */57 MyViewHolder myViewHolded = (MyViewHolder) holder;58 myViewHolded.colorBlock.setBackgroundColor((dateItem.getColor()));59 myViewHolded.colorName.setText(dateItem.getName());60 }61 62 63 //return item的数量64 @Override65 public int getItemCount() {66 return dateItems.size();67 }68 }
The layoutManager
如之前所说，LayoutManager主要负责数据怎样展示在屏幕上。我们还有三种选择：LinerlayoutManager，GridLayoutManager and StaggeredGirdLayoutManager。我们也可以创造我们自己的LayoutManager如果我们需要的话。在第一个测试中，我们使用的是LingerLayout，实现方式恒简单。
mLayoutManage = new LinearLayoutManager(this); mRecyclerView.setLayoutManager(mLayoutManage);
第二种LayoutManager
mLayoutManage = new GridLayoutManager(this,2); mRecyclerView.setLayoutManager(mLayoutManage);
HandLing item click evens
RecycleView没有onItemClickListener，相反的是，我们需要实现onClickListener 在我们的ViewHolder。
有许多的方法实现这一步，我将会事例一个简单的方式。
我们点击事件，将会打印item的颜色名字
public static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{ public TextView colorName; public View colorBlock; public MyViewHolder(View itemView) { super(itemView); /** Must call super()first */ colorName = (TextView) itemView.findViewById(R.id.colorName); colorBlock = itemView.findViewById(R.id.colorBlock); itemView.setOnClickListener(this); } @Override public void onClick(View v) { Log.d("MyViewHolder", "Item click:"+colorName.getText().toString()); } }
值得注意的是
itemView.setOnClickListener(this);View itemView 实际上是我们的 item main layout。
这只是冰上一角，RecyclerView真真强大的在于定制不同的组建，……。
人们很容易形容RecycleView作为一个更加个性化，灵活的ListView但这或与有点误导，尽管RecyclerView允许ListView相同的功能，但他们的核心或甚至理念是不同的。