Android程序设计-RecyclerView的使用
【定义】
看到这个标题，也许你会问什么是RecyclerView?其实开始的时候我也不知道- -，下面小编将带领大家领略RecyclerView的强大之处
【描述】
看完这个我想大家应该知道了吧，这个东西和ListView一样，只不过，这个…在设计的时候不需要考虑上述几个功能，即使要实现这几个功能，也是很简单的，仅仅需要几句话就可以搞定的
【使用】
使用的时候需要导入recyclerview-v7-21.0.0的jar包，然后在布局文件中添加这个控件
<android.support.v7.widget.RecyclerView/>
---------------------------------------------------------------我是一个帅帅的分割线-------------------------------------------------------
【案例】
小编将通过一个案例实现RecyclerView的使用，下面请看这个案例的实现效果
【关键步骤】
1.在布局文件中添加了对用的控件后，我们需要书写代码，既然和ListView肯定需要适配器，下面我们来看下适配器
package org.monster.recyclerviewdemo;
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.List;
/**
* Created by monster on 2015/7/9.
* 继承RecyclerView，实现ListView的效果
* RecyclerView中google强烈要求使用ViewHolder
*/
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder>{
private List<String> mData;
private Context context;
private LayoutInflater mInflater;
/**
* 声明一个接口，用于实现点击事件
*/
public interface OnItemClickListener{
void OnItemClick(int position,View view);
void OnItemLongClick(int position,View view);
}
private OnItemClickListener mOnItemClickListener;
public void setOnItemClickListener(OnItemClickListener listener){
this.mOnItemClickListener=listener;
}
/**构造方法的实现**/
public SimpleAdapter(List<String> mData,Context context){
this.mData=mData;
this.context=context;
mInflater=LayoutInflater.from(context);
}
/**
* 创建ViewHolder
* @param parent
* @param viewType
* @return
*/
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view=mInflater.inflate(R.layout.recycler_item,parent,false);
MyViewHolder viewHolder=new MyViewHolder(view);
return viewHolder;
}
/**
* 绑定ViewHolder类,即给控件赋值
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
holder.tv.setText(mData.get(position));
if (mOnItemClickListener!=null){
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView);
}
});
//longclickListener
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
int LayoutPosition=holder.getLayoutPosition(); //得到布局的position
mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView);
return false;
}
});
}
}
@Override
public int getItemCount() {
return mData.size();
}
public void addData(int position){
mData.add(position,"Insert One");
notifyItemInserted(position);
}
public void deleteData(int position){
mData.remove(position);
notifyItemRemoved(position);
}
}
/**
* ViewHolder类，这个类的作用主要用于实例化控件
*/
class MyViewHolder extends RecyclerView.ViewHolder{
TextView tv; //声明控件
public MyViewHolder(View itemView) {
super(itemView);
/**初始化控件**/
tv= (TextView) itemView.findViewById(R.id.tv);
}
}
ps:
代码中我们可以看到我们继承了RecyclerView.Adapter<MyViewHolder>，实现了未实现的方法，但是一定要注意，google在这里要求必须实现ViewHolder这个类，我们通过代码知道，通过设计了ViewHolder使我们的类更加的简洁了，更重要的是我们的代码更加的实用了。
2.我们来看下MainActivity中的代码：
package org.monster.recyclerviewdemo;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
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.Switch;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity {
private RecyclerView recyclerView;
private List<String> mDatas;
private SimpleAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initDatas();
initView();
adapter=new SimpleAdapter(mDatas,this);
recyclerView.setAdapter(adapter);
//设置RecyclerView的布局管理
LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
recyclerView.setLayoutManager(layoutManager);
//设置RecyclerView的item间的分割线
// recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
//设置RecyclerView的动画
recyclerView.setItemAnimator(new DefaultItemAnimator());
//设置监听事件
adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
@Override
public void OnItemClick(int position, View view) {
Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show();
}
@Override
public void OnItemLongClick(int position, View view) {
Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show();
}
});
}
private void initView() {
recyclerView= (RecyclerView) findViewById(R.id.RecyclerView);
}
/**
* 加载数据源
*/
private void initDatas() {
mDatas=new ArrayList<String>();
for(int i='A';i<'z';i++){
mDatas.add(" "+(char)i);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
switch (id){
case R.id.action_add:
adapter.addData(1);
break;
case R.id.action_delete:
adapter.deleteData(1);
break;
case R.id.action_listview:
recyclerView.setLayoutManager(new LinearLayoutManager(this));
break;
case R.id.action_gridview:
recyclerView.setLayoutManager(new GridLayoutManager(this,3));
break;
case R.id.action_hor_gridview:
recyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.HORIZONTAL));
break;
case R.id.action_staggered:
Intent i=new Intent(this,StaggerActivity.class);
startActivity(i);
break;
}
return super.onOptionsItemSelected(item);
}
}
PS:
适配器的使用和ListView的使用一样，但是这时候当我们运行程序会发现没有分割线，整个页面成一个了，所以我们需要使用addItemDecoration添加分割线
设置RecyclerView的item间的分割线 recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
Comic Sans MS在分割线的部分我们需要引入github中的一个分割线文件：
package org.monster.recyclerviewdemo;
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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.util.Log;
import android.view.View;
/**
* This class is from the v7 samples of the Android SDK. It's not by me!
* <p/>
* See the license above for details.
*/
public class DividerItemDecoration extends RecyclerView.ItemDecoration
{
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)
{
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
setOrientation(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 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);
}
}
}
如何在RecyleView中设计布局管理？这个布局管理可以让你的页面实现ListView和GridView的自由切换
//设置RecyclerView的布局管理 LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false); recyclerView.setLayoutManager(layoutManager);
如何咋RecyclerView中增加添加item和删除item的动画？
（附录动画效果的Github链接：https://github.com/gabrielemariotti/RecyclerViewItemAnimators）
//设置RecyclerView的动画 recyclerView.setItemAnimator(new DefaultItemAnimator());
如何在对Recycler中的item设置监听事件？这个监听事件系统不提供，需要我们手动编写
--->我们需要在适配器添加一个接口：
/** * 声明一个接口，用于实现点击事件 */ public interface OnItemClickListener{ void OnItemClick(int position,View view); void OnItemLongClick(int position,View view); } private OnItemClickListener mOnItemClickListener; public void setOnItemClickListener(OnItemClickListener listener){ this.mOnItemClickListener=listener; } /**构造方法的实现**/ public SimpleAdapter(List<String> mData,Context context){ this.mData=mData; this.context=context; mInflater=LayoutInflater.from(context); }--->在onBindViewHolder中设置监听事件的方法
/** * 绑定ViewHolder类,即给控件赋值 * @param holder * @param position */ @Override public void onBindViewHolder(final MyViewHolder holder, final int position) { holder.tv.setText(mData.get(position)); if (mOnItemClickListener!=null){ holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemClick(LayoutPosition,holder.itemView); } }); //longclickListener holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { int LayoutPosition=holder.getLayoutPosition(); //得到布局的position mOnItemClickListener.OnItemLongClick(LayoutPosition,holder.itemView); return false; } }); } }--->>在MainActivity中调用如
//设置监听事件 adapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() { @Override public void OnItemClick(int position, View view) { Toast.makeText(MainActivity.this,"Click: "+position,Toast.LENGTH_SHORT).show(); } @Override public void OnItemLongClick(int position, View view) { Toast.makeText(MainActivity.this,"Long click: "+position,Toast.LENGTH_SHORT).show(); } });
上述即为RecyclerView的简单实用，程序中的其他样式敬请参考【源码】
【视频】
【源码】
