RecyclerView使用_recyclerview是什么

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发布于 2022-11-01 13:46:32

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发布于 2022-11-01 13:46:32

文章被收录于专栏：全栈程序员必看

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本文目录

RecyclerView概述

RecyclerView是官方在5.0之后新添加的控件，推出用来替代传统的ListView和GridView列表控件。

RecyclerView使用-基础篇

第一步：添加RecyclerView

**方法1：**点开任意一个布局文件，找到左边的RecyclerView控件，点击旁边的按钮即可添加RecyclerView。

**方法2：**在build.gradle文件中添加依赖

    implementation 'androidx.recyclerview:recyclerview:1.1.0'

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第二步：添加布局文件

在布局文件activity_main.xml中先添加RecyclerView控件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

再添加一个item_list.xml的布局文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="29dp"
android:layout_marginTop="33dp"
android:text="标题"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="4dp"
android:layout_marginTop="18dp"
android:text="内容"
app:layout_constraintStart_toStartOf="@+id/textView"
app:layout_constraintTop_toBottomOf="@+id/textView" />
</androidx.constraintlayout.widget.ConstraintLayout>

第三步：添加逻辑代码

首先定一个实体类如下：

public class News { 

public String title; // 标题
public String content; //内容
}

然后在MainActivity中定义内部类 ViewHolder类、 MyAdapter类以及设置RecyclerView相关逻辑

package com.lucashu.recyclerview;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity { 

RecyclerView mRecyclerView;
MyAdapter mMyAdapter ;
List<News> mNewsList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) { 

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.recyclerview);
// 构造一些数据
for (int i = 0; i < 50; i++) { 

News news = new News();
news.title = "标题" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter = new MyAdapter();
mRecyclerView.setAdapter(mMyAdapter);
LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
mRecyclerView.setLayoutManager(layoutManager);
}
class MyAdapter extends RecyclerView.Adapter<MyViewHoder> { 

@NonNull
@Override
public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { 

View view = View.inflate(MainActivity.this, R.layout.item_list, null);
MyViewHoder myViewHoder = new MyViewHoder(view);
return myViewHoder;
}
@Override
public void onBindViewHolder(@NonNull MyViewHoder holder, int position) { 

News news = mNewsList.get(position);
holder.mTitleTv.setText(news.title);
holder.mTitleContent.setText(news.content);
}
@Override
public int getItemCount() { 

return mNewsList.size();
}
}
class MyViewHoder extends RecyclerView.ViewHolder { 

TextView mTitleTv;
TextView mTitleContent;
public MyViewHoder(@NonNull View itemView) { 

super(itemView);
mTitleTv = itemView.findViewById(R.id.textView);
mTitleContent = itemView.findViewById(R.id.textView2);
}
}
}

运行效果

RecyclerView使用-进阶篇

布局管理器

RecyclerView提供了三种布局管理器即：

LinearLayoutManager 线性布局管理器
StaggeredGridLayoutManager 瀑布流布局管理器
GridLayoutManager 网格布局管理器

线性布局管理器

这三种布局管理器都是通过setLayoutManager方法来设置 LinearLayoutManager 还可以设置横向滚动，只需将前面MainActivity中的layoutManager加一句代码即可：

 LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
layoutManager.setOrientation(RecyclerView.HORIZONTAL);
mRecyclerView.setLayoutManager(layoutManager);

网格布局管理器

如果让一行显示多个，可以设置 GridLayoutManager网格布局管理器来实现

  GridLayoutManager layoutManager = new GridLayoutManager(MainActivity.this,3);
// layoutManager.setOrientation(RecyclerView.HORIZONTAL); 也能设置横向滚动
mRecyclerView.setLayoutManager(layoutManager);

ItemDecoration

通过给设置ItemDecoration 来装饰Item的效果，比如我们要设置间隔线

DividerItemDecoration mDivider = new    
DividerItemDecoration(this,DividerItemDecoration.VERTICAL);
mRecyclerView.addItemDecoration(mDivider);

Item 动画

RecyclerView提供了默认的ItemAnimator实现类：DefaultItemAnimator。该类可以帮我们实现一些炫酷的动画效果

DefaultItemAnimator itemAnimator = new DefaultItemAnimator();
defaultItemAnimator.setAddDuration(1000);
defaultItemAnimator.setRemoveDuration(1000);
mRecyclerView.setItemAnimator(itemAnimator);

在MainActivity中添加了两个按钮，一个添加item，一个删除item

Button button = findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() { 

@Override
public void onClick(View v) { 

News news = new News();
news.title = "标题 新内容" ;
news.content = "内容 新内容" ;
mNewsList.add(1,news);
mMyAdapter.notifyItemInserted(1);
}
});
Button button1 = findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() { 

@Override
public void onClick(View v) { 

mNewsList.remove(0);
mMyAdapter.notifyItemMoved(0,1);
}
});

效果如下：

Item 点击

可以通过对整个Item文件的根布局添加一个点击事件来实现Item的点击

效果如下：

RecyclerView使用-高级篇（上拉刷新下拉加载更多）

通常RecyclerView使用的时候需要配合上拉刷新下拉加载更多的功能我们通过开源控件SmartRefreshLayout来实现 SmartRefreshLayout官网：https://github.com/scwang90/SmartRefreshLayout 使用方法如下：

第一步：添加依赖

在gradle文件中添加

implementation 'com.scwang.smartrefresh:SmartRefreshLayout:1.1.2'   
implementation 'com.scwang.smartrefresh:SmartRefreshHeader:1.1.2'

第二步：布局文件

在activity_main.xml中SmartRefreshLayout控件将RecyclerView包裹起来

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<com.scwang.smartrefresh.layout.SmartRefreshLayout
android:id="@+id/refreshLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</com.scwang.smartrefresh.layout.SmartRefreshLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

第三步：逻辑代码

在MainActivity的onCreate方法中添加下拉刷新和上拉加载更多的功能

下拉刷新：

RefreshLayout refreshLayout = findViewById(R.id.refreshLayout);
refreshLayout.setOnRefreshListener(new OnRefreshListener() { 

@Override
public void onRefresh(RefreshLayout refreshlayout) { 

refreshlayout.finishRefresh(2000/*,false*/);//传入false表示刷新失败
mNewsList.clear();
for (int i = 0; i < 10; i++) { 

News news = new News();
news.title = "标题 新内容" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter.notifyDataSetChanged();
}
});

上拉加载更多

 refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() { 

@Override
public void onLoadMore(RefreshLayout refreshlayout) { 

refreshlayout.finishLoadMore(2000/*,false*/);//传入false表示加载失败
for (int i = 0; i < 10; i++) { 

News news = new News();
news.title = "标题 新内容" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter.notifyDataSetChanged();
}
});

效果如下：

完整代码

MainActivity.java文件

package com.lucashu.recyclerview;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import com.scwang.smartrefresh.layout.api.RefreshLayout;
import com.scwang.smartrefresh.layout.listener.OnLoadMoreListener;
import com.scwang.smartrefresh.layout.listener.OnRefreshListener;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity { 

RecyclerView mRecyclerView;
MyAdapter mMyAdapter ;
List<News> mNewsList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) { 

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.recyclerview);
// 构造一些数据
for (int i = 0; i < 10; i++) { 

News news = new News();
news.title = "标题" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter = new MyAdapter();
mRecyclerView.setAdapter(mMyAdapter);
LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
mRecyclerView.setLayoutManager(layoutManager);
RefreshLayout refreshLayout = findViewById(R.id.refreshLayout);
refreshLayout.setOnRefreshListener(new OnRefreshListener() { 

@Override
public void onRefresh(RefreshLayout refreshlayout) { 

refreshlayout.finishRefresh(2000/*,false*/);//传入false表示刷新失败
mNewsList.clear();
for (int i = 0; i < 10; i++) { 

News news = new News();
news.title = "标题 新内容" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter.notifyDataSetChanged();
}
});
refreshLayout.setOnLoadMoreListener(new OnLoadMoreListener() { 

@Override
public void onLoadMore(RefreshLayout refreshlayout) { 

refreshlayout.finishLoadMore(2000/*,false*/);//传入false表示加载失败
for (int i = 0; i < 10; i++) { 

News news = new News();
news.title = "标题 新内容" + i;
news.content = "内容" + i;
mNewsList.add(news);
}
mMyAdapter.notifyDataSetChanged();
}
});
}
class MyAdapter extends RecyclerView.Adapter<MyViewHoder> { 

@NonNull
@Override
public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { 

View view = View.inflate(MainActivity.this, R.layout.item_list, null);
MyViewHoder myViewHoder = new MyViewHoder(view);
return myViewHoder;
}
@Override
public void onBindViewHolder(@NonNull MyViewHoder holder, final int position) { 

News news = mNewsList.get(position);
holder.mTitleTv.setText(news.title);
holder.mTitleContent.setText(news.content);
holder.mRootView.setOnClickListener(new View.OnClickListener() { 

@Override
public void onClick(View v) { 

Toast.makeText(MainActivity.this,"点击了："+ position,Toast.LENGTH_LONG).show();
}
});
}
@Override
public int getItemCount() { 

return mNewsList.size();
}
}
class MyViewHoder extends RecyclerView.ViewHolder { 

TextView mTitleTv;
TextView mTitleContent;
ConstraintLayout mRootView;
public MyViewHoder(@NonNull View itemView) { 

super(itemView);
mTitleTv = itemView.findViewById(R.id.textView);
mTitleContent = itemView.findViewById(R.id.textView2);
mRootView = itemView.findViewById(R.id.rootview);
}
}
}

activity_main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<com.scwang.smartrefresh.layout.SmartRefreshLayout
android:id="@+id/refreshLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</com.scwang.smartrefresh.layout.SmartRefreshLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

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原始发表：2022年10月23日，如有侵权请联系 cloudcommunity@tencent.com 删除

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