精通RecyclerView：打造ListView、GridView、瀑布流；学会添加分割线、 添加删除动画 、Item点击事件
在上一篇Android用RecyclerView练手仿美团分类界面写了RecyclerView的基本用法，
今天想想，在这里重新学习一下RecyclerView的完整用法。包括如何打造一个普通的ListView和横向的ListView、普通的GridView和横向的GridView、如何添加分割线、
还有就是添加和删除的动画、以及如何设置Item的OnClick事件监听。这里包含了各种用法，也算是一个入门的用法，已经掌握的高手请略过。
先看总体效果图
一.RecyclerView介绍
RecyclerView 是Android L版本中新添加的一个用来取代ListView和GridView的SDK，它的灵活性与可替代性比ListView更好。
接下来通过一系列的内容讲解如何使用RecyclerView,彻底抛弃ListView和GridView。
二.RecyclerView架构
三.RecyclerView的优点
1.RecyclerView封装了ViewHolder的回收复用，也就是说RecyclerView标准化了ViewHolder，
编写Adapter面向的是ViewHolder而不再是View了，复用的 逻辑被封装了，写起来更加简单。2.提供了一种插拔式的体验，高度的解耦，异常的灵活，针对一个Item的显示RecyclerView专门抽取出了相应的类，
来控制Item的显示，使其的扩展性非常强。例如：你想控制横向或者纵向滑动列表效果可以通过LinearLayoutManager这个类来进行控制
(与GridView效果对应的是GridLayoutManager,与瀑布流对应的还有StaggeredGridLayoutManager等)，
也就是说RecyclerView不再拘泥于ListView的线性展示方式，它也可以实现GridView的效果等多种效果。你想控制Item的分隔线，
可以通过继承RecyclerView的ItemDecoration这个类，然后针对自己的业务需求去抒写代码。3.可以控制Item增删的动画，可以通过ItemAnimator这个类进行控制，当然针对增删的动画，RecyclerView有其自己默认的实现。
四.RecyclerView实现三部曲
第一步：设置布局管理器
用来确定每一个item如何进行排列摆放:
LinearLayoutManager 相当于ListView的效果
GridLayoutManager相当于GridView的效果
StaggeredGridLayoutManager 瀑布流
第二步：添加分割线
我们用到了网上流传的万能分割线DividerItemDecoration和DividerGridItemDecoration，首先在style.xml里面定义分割线图片：
1.先在drawable中新建divider.xml
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <solid android:color="@color/colorAccent"/> <size android:height="1dp" android:width="1dp"/> </shape>
2.然后在style.xml中设置android:listDivider
<item name="android:listDivider">@drawable/divider</item>
第三步：设置适配器
package cn.bluemobi.dylan.recyclerviewdemo2;
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;
import java.util.List;
/**
* RecyclerView的适配器
* Created by yuandl on 2016-11-01.
*/
public class RvAdapter extends RecyclerView.Adapter<RvAdapter.MyViewHolder> {
private Context context;
private List<Integer> datas;
/**
* item的点击事件的长按事件接口
*/
private OnItemClickListener onItemClickListener;
/**
* 瀑布流时的item随机高度
*/
private List<Integer> heights = new ArrayList<>();
/**
* 不同的类型设置item不同的高度
*
* @param type
*/
private int type = 0;
public RvAdapter(Context context, List<Integer> datas) {
this.context = context;
this.datas = datas;
for (int i : datas) {
int height = (int) (Math.random() * 100 + 300);
heights.add(height);
}
}
public void setType(int type) {
this.type = type;
}
/**
* 设置点击事件
*
* @param onItemClickListener
*/
public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
this.onItemClickListener = onItemClickListener;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View contentView = LayoutInflater.from(context).inflate(R.layout.item, parent, false);
MyViewHolder viewHolder = new MyViewHolder(contentView);
return viewHolder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, final int position) {
RecyclerView.LayoutParams layoutParams;
if (type == 0) {
layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
} else if (type == 1) {
layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
} else {
layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, heights.get(position));
layoutParams.setMargins(2, 2, 2, 2);
}
holder.itemView.setLayoutParams(layoutParams);
holder.imageView.setImageResource(datas.get(position));
holder.tv.setText("分类" + position);
/**设置item点击监听**/
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (onItemClickListener != null) {
onItemClickListener.onItemClickListener(position, datas.get(position));
}
}
});
}
@Override
public int getItemCount() {
return datas == null ? 0 : datas.size();
}
/**
* 用于缓存的ViewHolder
*/
public class MyViewHolder extends RecyclerView.ViewHolder {
private ImageView imageView;
public TextView tv;
public MyViewHolder(View itemView) {
super(itemView);
imageView = (ImageView) itemView.findViewById(R.id.iv);
tv = (TextView) itemView.findViewById(R.id.tv);
}
}
/**
* 设置item监听的接口
*/
public interface OnItemClickListener {
void onItemClickListener(int position, Integer data);
}
}五.打造各种效果
1.竖向的ListView
rv.setBackgroundColor(Color.TRANSPARENT); rv.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)); rvAdapter.setType(0); rv.removeItemDecoration(itemDecoration); rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT)); itemDecoration = new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST); rv.addItemDecoration(itemDecoration);
2.横向的ListView
rvAdapter.setType(1); rv.removeItemDecoration(itemDecoration); rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT)); rv.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)); itemDecoration = new DividerItemDecoration(this, DividerItemDecoration.HORIZONTAL_LIST); rv.addItemDecoration(itemDecoration);
3.竖向的GridView
rvAdapter.setType(1); rv.setBackgroundColor(Color.TRANSPARENT); rv.removeItemDecoration(itemDecoration); rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT)); rv.setLayoutManager(new GridLayoutManager(this, 5)); itemDecoration = new DividerGridItemDecoration(this); rv.addItemDecoration(itemDecoration);
4.横向的GridView
rvAdapter.setType(1); rv.setBackgroundColor(Color.TRANSPARENT); rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT)); rv.removeItemDecoration(itemDecoration); rv.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.HORIZONTAL)); itemDecoration = new DividerGridItemDecoration(this); rv.addItemDecoration(itemDecoration);
5.竖向的瀑布流
rvAdapter.setType(3); rv.setBackgroundColor(getResources().getColor(R.color.colorAccent)); rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT)); rv.removeItemDecoration(itemDecoration); rv.setLayoutManager(new StaggeredGridLayoutManager(5, StaggeredGridLayoutManager.VERTICAL));
6.添加和删除动画
/**添加一个数据**/ rvAdapter.notifyItemInserted(1); /**删除一个数据**/ rvAdapter.notifyItemRemoved(1);
六.GiHub
作者：DylanAndroid