Recycler实现瀑布流

（开发环境Android studio）

首先，在开发环境中添加引用（在外层的build.gradle文件下的dependencies里面添加如下引用）

implementation 'com.android.support:recyclerview-v7:28.0.0'

implementation 'com.android.support:cardview-v7:28.0.0'

创造我们需要的Java Bean对象类 myDogs.java

对应代码如下：

public class myDogs {

    private String dogName;

    private int imgId;

    public String getDogName() {

        return dogName;

    }

    public void setDogName(String dogName) {

        this.dogName = dogName;

    }

    public int getImgId() {

        return imgId;

    }

    public void setImgId(int imgId) {

        this.imgId = imgId;

    }

}

对于我们的RecyclelerView子项，我们创建子项布局文件

my_dog_item.xml(对于子项，我们使用cardview布局，这也就是第刚开始的时候第二行引用的作用)

<?xml version="1.0" encoding="utf-8"?>

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    android:layout_margin="5dp"

    android:padding="4dp"

    app:cardBackgroundColor="#ffffffff"

    app:cardCornerRadius="15dp">

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:gravity="center_horizontal"

        android:orientation="vertical">

        <ImageView

            android:id="@+id/myDog_image"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:scaleType="centerCrop" />

        <TextView

            android:id="@+id/myDog_name"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content" />

    </LinearLayout>

</android.support.v7.widget.CardView>

其中:

cardCornerRadius="15dp"

保证每一个子项拥有15dp的圆角

然后创建适配器myDogAdapter.java从RecyclerView.Adapter<>继承

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.ImageView;

import android.widget.TextView;

import java.util.List;

public class myDogAdapter extends RecyclerView.Adapter<myDogAdapter.myDogViewHolder> {

    private Context mcontext;

    private List<myDog> myDogs;

    public myDogAdapter(List<myDog> myDogs , Context context){

        this.myDogs = myDogs;

        this.mcontext = context;

    }

    @NonNull

    @Override

    public myDogAdapter.myDogViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {

        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.my_dog_item,viewGroup,false);

        return new myDogViewHolder(view);

    }

    @Override

    public void onBindViewHolder(@NonNull myDogAdapter.myDogViewHolder holder, int position) {

        myDog myDogDemo = myDogs.get(position);

        holder.myDogImage.setImageResource(myDogDemo.getImgId());

        holder.myDogName.setText(myDogDemo.getDogName());

    }

    @Override

    public int getItemCount() {

        return myDogs.size();

    }

    class myDogViewHolder extends RecyclerView.ViewHolder{

        ImageView myDogImage;

        TextView myDogName;

        public myDogViewHolder(@NonNull View itemView) {

            super(itemView);

            myDogImage = itemView.findViewById(R.id.myDog_image);

            myDogName = itemView.findViewById(R.id.myDog_name);

        }

    }

}

然后，编写MainActivity里面的内容：

<?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"

    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView

        android:id="@+id/recycler_view"

        android:layout_width="match_parent"

        android:layout_height="match_parent" />

</LinearLayout>

这里面只放置了一个RecyclerView并让它填充布局

然后我们开始编写MainActivity.java里面的内容

package edu.henu.www.recyclelerview;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.StaggeredGridLayoutManager;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;

import java.util.List;

import java.util.ListIterator;

public class MainActivity extends AppCompatActivity {

    //创建与布局中相对应的对象；

    private RecyclerView recyclerView;

    //创建用于显示的对象集；

    private List<myDog> myDogs = new ArrayList<>();

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //将布局中相应的对象传入

        recyclerView = this.findViewById(R.id.recycler_view);

        //设置瀑布流核心代码，设置瀑布流列数，并设置瀑布流方向；

        StaggeredGridLayoutManager recyclerViewLayoutManager = new StaggeredGridLayoutManager(2 , StaggeredGridLayoutManager.VERTICAL);

        //设置布局管理器

        recyclerView.setLayoutManager(recyclerViewLayoutManager);

        //初始化对象；

        initDogs();

        //创建Adapter对象；

        myDogAdapter adapter = new myDogAdapter(this.myDogs , this);

        //设置适配器

        recyclerView.setAdapter(adapter);

    }

    private void initDogs(){

        myDog dog;

        for (int i = 0; i < 10; i++) {

            dog = new myDog("小狗狗" + i,R.drawable.d1);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i ,R.drawable.d2);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d3);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d4);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d5);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d6);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d6);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d7);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d8);

            myDogs.add(dog);

            dog = new myDog("小狗狗" + i,R.drawable.d9);

            myDogs.add(dog);

        }

    }

}

图片资源需要自己填充到Android项目目录下

实现效果如图

参考文章：https://www.jianshu.com/p/02be426fda0a