【番外篇】Android RecyclerView使用详解

移动开发 2024-11-01 22:28:26 阅读次数: 0

 

目录

 概述

一、RecyclerView基础使用

第一步：在build.gradle中添加依赖

第二步：添加RecyclerView

第三步：再添加一个news_item_layout.xml的布局文件,用于显示一条数据​编辑

第四步：添加逻辑代码

二、RecyclerView进阶使用：通过网络请求得到数据

如有不清楚，或者本文章中有错误的地方，本人虚心接受指正。

下一期:Android Studio动画效果的使用详解。

概述

RecyclerView是Android中非常受欢迎的控件，RecyclerView是官方在Android5.0之后新添加的控件，推出用来替代传统的ListView和GridView列表控件，所以如果你还在使用ListView的话可以替换为RecyclerView了。

对于RecyclerView的使用根据实际项目进行说明，一些功能可能是你现在正在做的，对你有帮助也说不定。

一、RecyclerView基础使用

第一步：在build.gradle中添加依赖

implementation ("androidx.recyclerview:recyclerview:1.1.0")//可横向滚动

第二步：添加RecyclerView

点开一个布局文件，找到RecyclerView控件，拖动到要添加的位置即可添加RecyclerView。ea3d6b270c4940949fb84e129a5d4120.gif

xml代码如下：

<?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.constraintlayout.widget.ConstraintLayout
        android:id="@+id/constraintLayout"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginTop="1dp"
        android:background="#6750A4"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="实例"
            android:textColor="#FFFFFF"
            android:textSize="16sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="409dp"
        android:layout_height="688dp"
        android:layout_marginTop="1dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/constraintLayout">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycleview"
            android:layout_width="409dp"
            android:layout_height="688dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

第三步：再添加一个news_item_layout.xml的布局文件,用于显示一条数据a04ee2311bb84282b72b16e7d6700343.png

在根布局上面设置好每条显示的数据的长宽，并添加内容到根布局里面。

代码如下：

<?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="90dp">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:text="title"
        android:textColor="#000000"
        android:textSize="18sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="5dp"
        android:text="content"
        android:textColor="#707070"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2" />
</androidx.constraintlayout.widget.ConstraintLayout>

第四步：添加逻辑代码

定义一个实体类:

d8966211092e496fa1eaa3a9cfc17444.png

实体类代码如下：

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

首先是内部类 MyViewHolder类：用于初始化控件

class MyViewHoder extends RecyclerView.ViewHolder {
        TextView title;
        TextView content;

        public MyViewHoder(@NonNull View itemView) {
            super(itemView);
            title = itemView.findViewById(R.id.textView2);
            content = itemView.findViewById(R.id.textView3);
        }
    }

再就是内部类 MyAdapter类：将添加到的数据与item进行绑定

class MyAdapter extends RecyclerView.Adapter<MyViewHoder> {

        //绑定item布局
        @NonNull
        @Override
        public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = View.inflate(MainActivity.this, R.layout.news_item_layout, null);
            MyViewHoder myViewHoder = new MyViewHoder(view);
            return myViewHoder;
        }

        //给item添加数据
        @Override
        public void onBindViewHolder(@NonNull MyViewHoder holder, int position) {
            News news = newsList.get(position);
            holder.title.setText(news.title);
            holder.content.setText(news.content);
        }

        //设置item条数
        @Override
        public int getItemCount() {
            return newsList.size();
        }
    }

最后就是构造数据： 

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = findViewById(R.id.recycleview);
        // 构造一些数据
        for (int i = 0; i < 100; i++) {
            News news = new News();
            news.title = "标题" + i;
            news.content = "内容" + i;
            newsList.add(news);
        }
        mMyAdapter = new MyAdapter();
        mRecyclerView.setAdapter(mMyAdapter);
        LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
        mRecyclerView.setLayoutManager(layoutManager);
    }

完整 MainActivity.java 代码： 

package com.example.retrofit;

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> newsList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = findViewById(R.id.recycleview);
        // 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;
            newsList.add(news);
        }
        mMyAdapter = new MyAdapter();
        mRecyclerView.setAdapter(mMyAdapter);
        LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
        mRecyclerView.setLayoutManager(layoutManager);
    }

    class MyAdapter extends RecyclerView.Adapter<MyViewHoder> {

        //绑定item布局
        @NonNull
        @Override
        public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = View.inflate(MainActivity.this, R.layout.news_item_layout, null);
            MyViewHoder myViewHoder = new MyViewHoder(view);
            return myViewHoder;
        }

        //给item添加数据
        @Override
        public void onBindViewHolder(@NonNull MyViewHoder holder, int position) {
            News news = newsList.get(position);
            holder.title.setText(news.title);
            holder.content.setText(news.content);
        }

        //设置item条数
        @Override
        public int getItemCount() {
            return newsList.size();
        }
    }

    class MyViewHoder extends RecyclerView.ViewHolder {
        TextView title;
        TextView content;

        public MyViewHoder(@NonNull View itemView) {
            super(itemView);
            title = itemView.findViewById(R.id.textView2);
            content = itemView.findViewById(R.id.textView3);
        }
    }
}

若要实现横向滑动：在 MainActivity.java 添加一句如下代码

layoutManager.setOrientation(RecyclerView.HORIZONTAL);

335eb2b871e841118d0efe056e5ed13f.png

若要每行显示多条数据，可对代码做如下修改：

mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));//每行三个

f88c94928fc6487386d4ef5c7dda9cd8.png

 运行效果如下：dbd9652396a3436181e444bbde2810b6.gif6846e7c868b84768b6615d374e65f6cf.gifdef9b2e369e643d4a215dff099853987.gif

二、RecyclerView进阶使用：通过网络请求得到数据

前期准备：添加依赖包：

implementation("com.squareup.okhttp3:okhttp:4.11.0")
implementation ("com.squareup.retrofit2:retrofit:2.9.0")
implementation ("com.squareup.retrofit2:converter-gson:2.9.0")

implementation ("io.github.youth5201314:banner:2.2.3")
implementation ("com.github.bumptech.glide:glide:4.15.1")
implementation ("com.google.code.gson:gson:2.10.1")

添加网络请求权限：

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
android:allowBackup="true"

58b9d756a5044cc1ba2471f61064b975.png

添加一些数据到mock中去（useMock 免费在线Mock平台 Api数据模拟助手）

重新构造实体类：0f9cf70cd0154954b349d4ec7a1c4553.png

获取网络数据，将网络数据赋值给newsDTOList数组

// 构造一些数据
        Request request = new Request.Builder()
                .url("https://detail.usemock.com/shiyan")
                .get().build();
        OkHttpClient okHttpClient = new OkHttpClient();
        Call call = okHttpClient.newCall(request);
        //构造item数据
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NonNull Call call, @NonNull IOException e) {
            }

            @Override
            public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
                String result = response.body().string();
                MainActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            Gson gson = new Gson();
                            News news = gson.fromJson(result,News.class);
                            newsDTOList.addAll(news.news);
                            mMyAdapter.notifyDataSetChanged();
                        }catch (Exception e){
                            throw new RuntimeException(e);
                        }
                    }
                });
            }
        });

再对MainActivity中定义内部类 ViewHolder类、 MyAdapter类以及设置RecyclerView相关逻辑的修改。具体操作很简单，这里省略，下面是完整的代码,供参考：

MainActivity.java代码：

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.GridLayoutManager;
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.ImageView;
import android.widget.TextView;

import com.bumptech.glide.Glide;
import com.google.gson.Gson;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {
    RecyclerView mRecyclerView;
    MyAdapter mMyAdapter ;
    List<News.NewsDTO> newsDTOList = new ArrayList<>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = findViewById(R.id.recycleview);


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

        // 构造一些数据
        Request request = new Request.Builder()
                .url("https://detail.usemock.com/shiyan")
                .get().build();
        OkHttpClient okHttpClient = new OkHttpClient();
        Call call = okHttpClient.newCall(request);
        //构造item数据
        call.enqueue(new Callback() {
            @Override
            public void onFailure(@NonNull Call call, @NonNull IOException e) {
            }

            @Override
            public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
                String result = response.body().string();
                MainActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            Gson gson = new Gson();
                            News news = gson.fromJson(result,News.class);
                            newsDTOList.addAll(news.news);
                            mMyAdapter.notifyDataSetChanged();
                        }catch (Exception e){
                            throw new RuntimeException(e);
                        }
                    }
                });
            }
        });




        mMyAdapter = new MyAdapter();
        mRecyclerView.setAdapter(mMyAdapter);
        //mRecyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this,3));//每行三个
        LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
        //layoutManager.setOrientation(RecyclerView.HORIZONTAL);
        mRecyclerView.setLayoutManager(layoutManager);
    }

    class MyAdapter extends RecyclerView.Adapter<MyViewHoder> {

        //绑定item布局
        @NonNull
        @Override
        public MyViewHoder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = View.inflate(MainActivity.this, R.layout.news_item_layout, null);
            MyViewHoder myViewHoder = new MyViewHoder(view);
            return myViewHoder;
        }

        //给item添加数据
        @Override
        public void onBindViewHolder(@NonNull MyViewHoder holder, int position) {
            News.NewsDTO newsDTO = newsDTOList.get(position);
            holder.title.setText(newsDTO.title);
            Glide.with(MainActivity.this).load(newsDTO.content).into(holder.content);
        }

        //设置item条数
        @Override
        public int getItemCount() {
            return newsDTOList.size();
        }
    }

    class MyViewHoder extends RecyclerView.ViewHolder {
        TextView title;
        ImageView content;

        public MyViewHoder(@NonNull View itemView) {
            super(itemView);
            title = itemView.findViewById(R.id.textView2);
            content = itemView.findViewById(R.id.imageView);
        }
    }
}

activity_main.xml代码：

<?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.constraintlayout.widget.ConstraintLayout
        android:id="@+id/constraintLayout"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginTop="1dp"
        android:background="#6750A4"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="实例"
            android:textColor="#FFFFFF"
            android:textSize="16sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="409dp"
        android:layout_height="688dp"
        android:layout_marginTop="1dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/constraintLayout">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycleview"
            android:layout_width="409dp"
            android:layout_height="688dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

News.java代码：

import java.util.List;

public class News {

    @com.google.gson.annotations.SerializedName("news")
    public List<NewsDTO> news;


    public static class NewsDTO {
        @com.google.gson.annotations.SerializedName("title")
        public String title;
        @com.google.gson.annotations.SerializedName("content")
        public String content;
    }
}

 news_item_layout.xml代码:

<?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="200dp"
    android:layout_height="150dp">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:text="title"
        android:textColor="#000000"
        android:textSize="18sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        app:srcCompat="@drawable/ic_launcher_background" />

</androidx.constraintlayout.widget.ConstraintLayout>

运行效果:8b60299e829041809e1bf9f33486a435.gif

如有不清楚，或者本文章中有错误的地方，本人虚心接受指正。

下一期:Android Studio动画效果的使用详解。

猜你喜欢

转载自blog.csdn.net/qq_73830179/article/details/140857960
今日推荐
周排行
JAVA集合框架（一）-综述
sql两列相除，保留n位小数
Linux下常用压缩 解压命令与压缩比率对比
编程思想_操作符
shardingjdbc分库分表节点扩容
初识python： 反射
poi_04_整合项目
HashMap源码解析（JDK1.8）
JAVA学习笔记（1）——面向对象程序设计基础
顾客银行办理业务时，首先在取号机上取号，然后坐在椅子上等候业务员叫号时前往窗口办理业务，假设银行现在有3个窗口可办理业务，请采用信号量和PV操作描述顾取号等候叫号和银行业务员叫号办理业务的同步操作。
每日归档
更多
2025-02-25(0)
2025-02-24(0)
2025-02-23(0)
2025-02-22(0)
2025-02-21(0)
2025-02-20(0)
2025-02-19(0)
2025-02-18(0)
2025-02-17(0)
2025-02-16(0)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022