一、RecyclerView是什么
从Android 5.0开始,谷歌公司推出了一个用于大量数据展示的新控件RecylerView,可以用来代替传统的ListView,更加强大和灵活。RecyclerView是support-v7包中的新组件,是一个强大的滑动组件,与经典的ListView相比,同样拥有item回收复用的功能,这一点从它的名字Recyclerview即回收view也可以看出。
二、基本使用
1.引入依赖
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:recyclerview-v7:28.0.0'
implementation 'jp.wasabeef:recyclerview-animators:2.2.7'
2.主布局(activity_main.xml)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<Button
android:id="@+id/id_add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="增加" />
<Button
android:id="@+id/id_del"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="删除" />
<android.support.v7.widget.RecyclerView
android:id="@+id/id_recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
3.item布局(activity_itemview.xml)
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:background="@color/colorAccent"
android:layout_height="72dp">
<TextView
android:id="@+id/id_tv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" />
</FrameLayout>
4.自定义分割线,在res/drawable下新建divider.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size android:height="2dp" />
<gradient
android:centerColor="@color/colorCenter"
android:endColor="@color/colorEnd"
android:startColor="@color/colorStart"
android:type="linear"></gradient>
</shape>
5.将自定义的分割线在style.xml里进行应用
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
<item name="android:listDivider">@drawable/divider</item>
</style>
</resources>
6.自定义分割线的工具类
package com.chen.recyclerviewtest;
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;
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);
}
}
}
7.MainActivity主界面
package com.chen.recyclerviewtest;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
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.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private List<String> mData;
private RecyclerView recyclerView;
private SimpleAdapter simpleAdapter;
private Button btn_add;
private Button btn_del;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
initView();
simpleAdapter=new SimpleAdapter(this,mData);
recyclerView.setAdapter(simpleAdapter);
//设置RecyclerView布局管理器
LinearLayoutManager linearLayoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
recyclerView.setLayoutManager(linearLayoutManager);
//recyclerView.setLayoutManager(new GridLayoutManager(this,2));
//设置分分割线
recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
//设置动画效果
recyclerView.setItemAnimator(new DefaultItemAnimator());
btn_add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
simpleAdapter.addData(mData.size());
}
});
btn_del.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
simpleAdapter.deleteData(mData.size()-1);
}
});
simpleAdapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(MainActivity.this,"点击"+position,Toast.LENGTH_SHORT).show();
}
@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(MainActivity.this,"长按"+position,Toast.LENGTH_SHORT).show();
}
});
}
private void initView(){
recyclerView=findViewById(R.id.id_recyclerView);
btn_add=findViewById(R.id.id_add);
btn_del=findViewById(R.id.id_del);
}
private void initData(){
mData=new ArrayList<String>();
for (int i='A';i<='z';i++){
mData.add(""+(char)i);
}
}
}
8.设置适配器
package com.chen.recyclerviewtest;
import android.content.Context;
import android.support.annotation.NonNull;
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;
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder> {
private LayoutInflater mInflater;
private Context mContext;
private List<String> mData;
public interface OnItemClickListener{
void onItemClick(View view,int position);
void onItemLongClick(View view,int position);
}
private OnItemClickListener onItemClickListener;
public void setOnItemClickListener(OnItemClickListener listener){
this.onItemClickListener=listener;
}
public SimpleAdapter(Context context,List<String> datas) {
this.mContext=context;
this.mData=datas;
mInflater=LayoutInflater.from(context);
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view=mInflater.inflate(R.layout.activity_itemview,viewGroup,false);
MyViewHolder viewHolder=new MyViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(@NonNull final MyViewHolder myViewHolder, final int i) {
myViewHolder.tv.setText(mData.get(i));
if(onItemClickListener!=null){
myViewHolder.itemView.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
onItemClickListener.onItemClick(myViewHolder.itemView,i);
}
});
myViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
onItemClickListener.onItemLongClick(myViewHolder.itemView,i);
return false;
}
});
}
}
@Override
public int getItemCount() {
return mData.size();
}
public void addData(int pos){
mData.add(pos,"哈哈哈");
notifyItemInserted(pos);
}
public void deleteData(int pos){
mData.remove(pos);
notifyItemRemoved(pos);
}
}
class MyViewHolder extends RecyclerView.ViewHolder {
TextView tv;
public MyViewHolder(@NonNull View itemView) {
super(itemView);
tv=itemView.findViewById(R.id.id_tv);
}
}
实现效果: