RecycleView使用总结二
一. 摘要
RecycleView没有像ListView那样直接提供添加headerView和footerView的方法，所以要实现这样的效果需要自己去实现。本文记录了通过item类型作为区分，来为列表添加headerView的整个流程。同时，记录了针对线性布局，网格布局，瀑布流布局的适配方法。
左右滑删除，拖动Item是很常见的功能。针对这些功能，安卓API中提供了相关的辅助类ItemTouchHelper等，借助于这些类，能够很方便的实现这些功能。本文也将针对ItemTouchHelper的具体使用方式。
二. 为RecycleView添加headerView
整体思路：通过item类型进行区分，把RecycleView的第一个Item作为头布局。整体实现思路非常简单，主要代码如下，详细代码会在文章最后给出。要注意的是对有没有添加headerView的判断，以及对应情况下，对Item位置的处理，如果添加了头布局，那么我们从数据集中拿Item的数据时就不能直接利用参数position来取，因为他们对应的位置已经变了。为此需要获取真实位置，即下面的getRealPosition()方法进行的处理。
private ListitemLists;
private View headView;
private final int HEAD_VIEW_TYPE=1;
private final int NORMAL_ITEM_TYPE=2;
public RecycleAdapter(List itemLists) {
this.itemLists = itemLists;
}
class ViewHolder extends RecyclerView.ViewHolder{
ImageView image;
TextView textView;
public ViewHolder(View view){
super(view);
if (view!=headView) {
image = view.findViewById(R.id.image);
textView = view.findViewById(R.id.text);
}
}
}
@Override
public RecycleAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType==HEAD_VIEW_TYPE)
return new ViewHolder(headView);
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.recycle_item,parent,false);
ViewHolder viewHolder=new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(RecycleAdapter.ViewHolder holder, int position) {
if (getItemViewType(position) == HEAD_VIEW_TYPE)
return;
try {
ItemInfo info = itemLists.get(getRealPosition(position));
holder.textView.setText(info.getTitle());
holder.image.setImageResource(info.getImgid());
}catch (Exception e){
Log.i("jm", "jm--onBindViewHolder: "+position);
}
}
private int getRealPosition(int position){
if (headView!=null){
return position-1;
}
return position;
}
@Override
public int getItemCount() {
return headView==null?itemLists.size():itemLists.size()+1;
}
@Override
public int getItemViewType(int position) {
if (headView!=null&&(position==0)){
return HEAD_VIEW_TYPE;
}
return NORMAL_ITEM_TYPE;
}
public void setHeaderView(View view){
headView=view;
notifyDataSetChanged();
}
public View getHeaderView(){
return headView;
} 通过以上处理，在需要添加headerView的地方直接调用setHeaderView()方法即可。在使用时发现，由于该方法的实质是把一个item当作头布局，所以，当使用线性布局时效果还行，但当我们采用网格布局或者瀑布流布局，这种一行要显示多个item时，添加的headerView将会直接作为一个item显示在第一个位置，效果如下，这显然不是我们想要的。
对此，我们需要针对GridLayoutManager和StaggeredGridLayoutManager做相应的处理，以下是针对两种所做的处理，方法引自网络，文章最后会给出链接。
针对GridLayoutManager，在适配器中添加如下代码，该方法的目的是在绑定RecycleView时，先判断出布局样式，再利用setSpanSizeLookup方法设置头布局跨多行显示，达到第一行只显示头布局的效果：
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if(manager instanceof GridLayoutManager) {
final GridLayoutManager gridManager = ((GridLayoutManager) manager);
gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return getItemViewType(position) == HEAD_VIEW_TYPE
? gridManager.getSpanCount() : 1;
}
});
}
}针对StaggeredGridLayoutManager，做如下处理：
@Override
public void onViewAttachedToWindow(ViewHolder holder) {
super.onViewAttachedToWindow(holder);
ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
if(lp != null
&& lp instanceof StaggeredGridLayoutManager.LayoutParams) {
StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
p.setFullSpan(holder.getLayoutPosition() == 0);
}
}至此可实现对三种布局的适配，适配器的全部代码如下：
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;
/**
* Created by jia on 2017/12/28.
*/
public class RecycleAdapter extends RecyclerView.Adapter {
private ListitemLists;
private View headView;
private final int HEAD_VIEW_TYPE=1;
private final int NORMAL_ITEM_TYPE=2;
public RecycleAdapter(List itemLists) {
this.itemLists = itemLists;
}
class ViewHolder extends RecyclerView.ViewHolder{
ImageView image;
TextView textView;
public ViewHolder(View view){
super(view);
if (view!=headView) {
image = view.findViewById(R.id.image);
textView = view.findViewById(R.id.text);
}
}
}
@Override
public RecycleAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType==HEAD_VIEW_TYPE)
return new ViewHolder(headView);
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.recycle_item,parent,false);
ViewHolder viewHolder=new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(RecycleAdapter.ViewHolder holder, int position) {
if (getItemViewType(position) == HEAD_VIEW_TYPE)
return;
try {
ItemInfo info = itemLists.get(getRealPosition(position));
holder.textView.setText(info.getTitle());
holder.image.setImageResource(info.getImgid());
}catch (Exception e){
Log.i("jm", "jm--onBindViewHolder: "+position);
}
}
private int getRealPosition(int position){
if (headView!=null){
return position-1;
}
return position;
}
@Override
public int getItemCount() {
return headView==null?itemLists.size():itemLists.size()+1;
}
@Override
public int getItemViewType(int position) {
if (headView!=null&&(position==0)){
return HEAD_VIEW_TYPE;
}
return NORMAL_ITEM_TYPE;
}
public void setHeaderView(View view){
headView=view;
notifyDataSetChanged();
}
public View getHeaderView(){
return headView;
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if(manager instanceof GridLayoutManager) {
final GridLayoutManager gridManager = ((GridLayoutManager) manager);
gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return getItemViewType(position) == HEAD_VIEW_TYPE
? gridManager.getSpanCount() : 1;
}
});
}
}
@Override
public void onViewAttachedToWindow(ViewHolder holder) {
super.onViewAttachedToWindow(holder);
ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
if(lp != null
&& lp instanceof StaggeredGridLayoutManager.LayoutParams) {
StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
p.setFullSpan(holder.getLayoutPosition() == 0);
}
}
} 实现效果如下：
三. 使用ItemTouchHelper实现RecycleView活动删除效果
最终要实现的效果如下，录屏软件出现bug，总录制偏。。：
ItemTouchHelper的使用时，只需以下几行代码：
//先实例化Callback
ItemTouchHelper.Callback callback = new SimpleItemTouchHelperCallback(myAdapter);
//用Callback构造ItemtouchHelper
ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
//调用ItemTouchHelper的attachToRecyclerView方法建立联系
touchHelper.attachToRecyclerView(recyclerView);从代码中，可以看出，我们只需要创建一个ItemTouchHelper对象，为其添加一个ItemTouchHelper.Callback接口，然后绑定到RecycleView上即可，具体来讲，就是通过以上绑定，我们就可以在ItemTouchHelper.Callback接口中捕获操作Item的操作，比如拖动和左右抛，在获取到相应操作的时候根据需要实现自己的逻辑，比如获取到左滑时，删除数据源中的一条数据，同时更新adapter，来达到滑动删除的效果。ItemTouchHelper.Callback中提供了很多回调，如下，根据文档注释以及方法名称可很快了解到他们的用途：
其中，常用的有如下一些：
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//在这里可以设置哪些方向上支持拖动，滑动等
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags = ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
return makeMovementFlags(dragFlags,swipeFlags);
}
@Override
public boolean isLongPressDragEnabled() {//返回true：长按后可拖动item，返回false：长按没效果
return true;
}
@Override
public boolean isItemViewSwipeEnabled() {//返回true:可实现抛动
return true;
}
//onMove方法中，是拖动item的回调，可以获取到拖动的item以及要拖动的位置
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return true;
}
//抛动后的回调
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
//对我们正在操作的item进行一些绘制操作，比如变更位置，添加一些额外的变化效果等
}除了以上，还可以设置滑动，以及拖动的响应阈值，该值是个比例因子，值越小，操作越灵敏，使用时在回调中直接复写设置相应的值即可：
/**
* Returns the fraction that the user should move the View to be considered as swiped.
* The fraction is calculated with respect to RecyclerView's bounds.
*
* Default value is .5f, which means, to swipe a View, user must move the View at least
* half of RecyclerView's width or height, depending on the swipe direction.
*
* @param viewHolder The ViewHolder that is being dragged.
* @return A float value that denotes the fraction of the View size. Default value
* is .5f .
*/
public float getSwipeThreshold(ViewHolder viewHolder) {
return .5f;
}
/**
* Returns the fraction that the user should move the View to be considered as it is
* dragged. After a view is moved this amount, ItemTouchHelper starts checking for Views
* below it for a possible drop.
*
* @param viewHolder The ViewHolder that is being dragged.
* @return A float value that denotes the fraction of the View size. Default value is
* .5f .
*/
public float getMoveThreshold(ViewHolder viewHolder) {
return .5f;
}
需要注意是：ItemTouchHelper在实现swipe或者move时都只是视觉上的效果，它告诉我们把谁给滑没了，在哪两个位置上产生了拖动交换的事件，但并没有真实的去处理数据更新显示，它只是告诉我们产生了这个操作，具体处理逻辑还需自己添加，比如执行了swipe操作，如果你不在方法回调中删除对应item的数据，刷新adapter，那么删除的item位置就会留下空白，如下：
最后，本篇的全部测试代码如下：
1.MainActivity.java
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
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.support.v7.widget.helper.ItemTouchHelper;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
RecyclerView recyclerView;
private ListitemList=new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView=findViewById(R.id.recycle);
initDatas();
LinearLayoutManager linearLayoutManager=new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
StaggeredGridLayoutManager staggeredGridLayoutManager=new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);
GridLayoutManager gridLayoutManager=new GridLayoutManager(this,3);
recyclerView.setLayoutManager(gridLayoutManager);
RecycleAdapter myAdapter=new RecycleAdapter(itemList);
recyclerView.scrollToPosition(1);
recyclerView.addItemDecoration(new CustomItemDecoration());
recyclerView.setAdapter(myAdapter);
View headView= LayoutInflater.from(this).inflate(R.layout.head_view_layout,recyclerView,false);
myAdapter.setHeaderView(headView);
headView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ProgressDialog progressDialog=new ProgressDialog(MainActivity.this);
progressDialog.setCanceledOnTouchOutside(false);
progressDialog.setTitle("测试");
progressDialog.setMessage("内容");
progressDialog.setButton(DialogInterface.BUTTON1, "取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(MainActivity.this,"点击了取消",Toast.LENGTH_SHORT).show();
}
});
progressDialog.show();
Toast.makeText(MainActivity.this,"点击了headerView",Toast.LENGTH_SHORT).show();
}
});
//先实例化Callback
ItemTouchHelper.Callback callback = new SimpleItemTouchHelperCallback(myAdapter);
//用Callback构造ItemtouchHelper
ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
//调用ItemTouchHelper的attachToRecyclerView方法建立联系
touchHelper.attachToRecyclerView(recyclerView);
}
void initDatas(){
for (int i=0;i<40;i++){
ItemInfo info=new ItemInfo();
info.setImgid(R.mipmap.ic_launcher);
info.setTitle("测试"+i);
itemList.add(info);
}
}
}
2.recycleView适配器RecycleAdapter,实现了一个辅助接口ItemTouchHelperAdapter，目的是在ItemTouchHelper.Callback接口中获取到抛动和拖动事件时能够，回调给适配器，进行数据和显示的更新。
/**
* Created by jia on 2018/5/30.
*/
public interface ItemTouchHelperAdapter {
//数据交换
void onItemMove(int fromPosition,int toPosition);
//数据删除
void onItemDissmiss(int position);
}
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;
public class RecycleAdapter extends RecyclerView.Adapter implements ItemTouchHelperAdapter {
private ListitemLists;
private View headView;
private final int HEAD_VIEW_TYPE=1;
private final int NORMAL_ITEM_TYPE=2;
public RecycleAdapter(List itemLists) {
this.itemLists = itemLists;
}
class ViewHolder extends RecyclerView.ViewHolder{
ImageView image;
TextView textView;
public ViewHolder(View view){
super(view);
if (view!=headView) {
image = view.findViewById(R.id.image);
textView = view.findViewById(R.id.text);
}
}
}
@Override
public RecycleAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType==HEAD_VIEW_TYPE)
return new ViewHolder(headView);
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.recycle_item,parent,false);
ViewHolder viewHolder=new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(RecycleAdapter.ViewHolder holder, int position) {
if (getItemViewType(position) == HEAD_VIEW_TYPE)
return;
try {
ItemInfo info = itemLists.get(getRealPosition(position));
holder.textView.setText(info.getTitle());
holder.image.setImageResource(info.getImgid());
}catch (Exception e){
Log.i("jm", "jm--onBindViewHolder: "+position);
}
}
private int getRealPosition(int position){
if (headView!=null){
return position-1;
}
return position;
}
@Override
public int getItemCount() {
return headView==null?itemLists.size():itemLists.size()+1;
}
@Override
public int getItemViewType(int position) {
if (headView!=null&&(position==0)){
return HEAD_VIEW_TYPE;
}
return NORMAL_ITEM_TYPE;
}
public void setHeaderView(View view){
headView=view;
notifyDataSetChanged();
}
public View getHeaderView(){
return headView;
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if(manager instanceof GridLayoutManager) {
final GridLayoutManager gridManager = ((GridLayoutManager) manager);
gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return getItemViewType(position) == HEAD_VIEW_TYPE
? gridManager.getSpanCount() : 1;
}
});
}
}
@Override
public void onViewAttachedToWindow(ViewHolder holder) {
super.onViewAttachedToWindow(holder);
ViewGroup.LayoutParams lp = holder.itemView.getLayoutParams();
if(lp != null
&& lp instanceof StaggeredGridLayoutManager.LayoutParams) {
StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
p.setFullSpan(holder.getLayoutPosition() == 0);
}
}
@Override
public void onItemMove(int fromPosition, int toPosition) {
//交换位置
if (getItemViewType(toPosition)==HEAD_VIEW_TYPE) //headView不可交换
return;
Collections.swap(itemLists,getRealPosition(fromPosition),getRealPosition(toPosition));
notifyItemMoved(fromPosition,toPosition);
}
@Override
public void onItemDissmiss(int position) {
//移除数据
itemLists.remove(getRealPosition(position));
notifyItemRemoved(position);
}
}
3.实现ItemTouchHelper.Callback接口，捕获事件，进行处理
import android.graphics.Canvas;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
public class SimpleItemTouchHelperCallback extends ItemTouchHelper.Callback{
private ItemTouchHelperAdapter mAdapter;
public SimpleItemTouchHelperCallback(ItemTouchHelperAdapter adapter){
mAdapter = adapter;
}
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//head view 不可滑动，拖动
if (recyclerView.getAdapter().getItemViewType(viewHolder.getAdapterPosition())==1){
return 0;
}
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags = ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;
return makeMovementFlags(dragFlags,swipeFlags);
}
@Override
public boolean isLongPressDragEnabled() {
return true;
}
@Override
public float getSwipeThreshold(RecyclerView.ViewHolder viewHolder) {
return super.getSwipeThreshold(viewHolder);
}
@Override
public boolean isItemViewSwipeEnabled() {
return true;
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//mAdapter.onItemMove(viewHolder.getAdapterPosition(),target.getAdapterPosition());
return true;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
//mAdapter.onItemDissmiss(viewHolder.getAdapterPosition());
}
// @Override
// public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
//
// if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
// final float alpha = 1 - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
// //viewHolder.itemView.setAlpha(alpha);
// //viewHolder.itemView.setTranslationX(dX);
// }
//
// }
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
final float alpha = 1 - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
viewHolder.itemView.setAlpha(alpha);
viewHolder.itemView.setTranslationX(dX);
}
}
}
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;
public class CustomItemDecoration extends RecyclerView.ItemDecoration {
private static final int HEAD_VIEW_TYPE=1;
private boolean hasHeadView=false;
Paint mPaint;
public CustomItemDecoration() {
super();
mPaint=new Paint();
mPaint.setColor(Color.RED);
mPaint.setStyle(Paint.Style.FILL);
}
/**
*在itemView绘制之前绘制，所以要通过getItemOffsets设置好距离，留出空间，防止被后绘得的itemView覆盖掉
* @param c
* @param parent
* @param state
*/
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDraw(c, parent, state);
// int childCount = parent.getChildCount();
// for ( int i = 0; i < childCount; i++ ) {
// View view = parent.getChildAt(i);
// int index = parent.getChildAdapterPosition(view);
// float top = view.getBottom();
// float extra=view.getHeight()/2;
// c.drawCircle(50, top+extra,20,mPaint);
// }
}
/**
* 在itemVie上面绘制，根据设计，使用canvas进行绘制即可
* @param c
* @param parent
* @param state
*/
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDrawOver(c, parent, state);
int childCount = parent.getChildCount();//当前可见的Item数，并不一定是全部
for ( int i = 0; i < childCount; i++ ) {
View view = parent.getChildAt(i);
int index = parent.getChildAdapterPosition(view);//获取adpter中对应的位置，获取item类型要使用它
if (parent.getAdapter().getItemViewType(index)==HEAD_VIEW_TYPE)//headView不绘制
continue;
float top = view.getTop();
float left=view.getLeft();
float right = view.getRight();
float bottom=view.getBottom();
float extra=view.getHeight()/2;
c.drawCircle(left-20, top+extra,20,mPaint);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setTextSize(15);
mPaint.setStrokeWidth(1);
Rect rect=new Rect();
mPaint.getTextBounds(i+"",0,(i+"").length(),rect);
c.drawText(i+"",left-20-rect.width()/2,top+extra+rect.height()/2,mPaint);
c.drawRect(left-10,top-10,right+10,bottom+10,mPaint);
}
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
int position=parent.getChildAdapterPosition(view);
if (parent.getAdapter().getItemViewType(position)!=HEAD_VIEW_TYPE)
{
outRect.top = 30;
outRect.left=30;
}
}
}至此，本文结束，作者依葫芦画瓢，对recycleView的相关基本使用流程有了一个大致了解，但对具体细节还不清楚，以后需要慢慢深化。
参考（引用）文章：
1.RecyclerView添加Header的正确方式
2.RecyclerView进阶：使用ItemTouchHelper实现拖拽和侧滑删除