Android---RecyclerView之简单瀑布流实现

1、自定义RecyclerView的xml控件 fruit_item.xml

<?xml version="1.0" encoding="utf-8"?><!--瀑布流--><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_margin="5dp">    <ImageView        android:id="@+id/fruit_image"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"/>    <TextView        android:id="@+id/fruit_name"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="left"        android:layout_marginLeft="10dp" /></LinearLayout>

2、新建fruit类，管理控件显示的数据

package com.mycompany.waterfallviewtest;/** * Created by sstek_mars on 2017/8/29. */public class Fruit {    private String name;    private int imageId;    public Fruit(String name, int imageId) {        this.name = name;        this.imageId = imageId;    }    public String getName() {        return name;    }    public int getImageId() {        return imageId;    }}

3、新建适配器

package com.mycompany.waterfallviewtest;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;/** * Created by sstek_mars on 2017/8/29. */public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder> {    private List<Fruit> mFruitList;    /**     * recyclerView适配器理解     * 1、定义一个内部类ViewHolder，ViewHolder要继承自RecyclerView.ViewHolder。然后ViewHolder的构造函数中要传入一个View参数，这个参数通常就是RecyclerView子项的最外层布局     * 2、通过findViewById()方法来获取到布局中的ImageView和TextView的实例     */    static class ViewHolder extends RecyclerView.ViewHolder {        ImageView fruitImage;        TextView fruitName;        public ViewHolder(View view) {            super(view);            fruitImage = (ImageView) view.findViewById(R.id.fruit_image);            fruitName = (TextView) view.findViewById(R.id.fruit_name);        }    }    /**     * 这个构造函数方法，用于把要展示的数据源传进来，并赋值给一个全局变量mFruitList。后续的操作都将在这个数据源的基础上进行。     */    public FruitAdapter(List<Fruit> fruitList) {        mFruitList = fruitList;    }    /**     * 由于FruitAdapter是继承于RecyclerView.Adapter的，那么就必须重写onCreateViewHolder()/onBindViewHolder()/getItemCount()     *     * onCreateViewHolder():用于创建ViewHolder实例，我们在这个方法化悲愤fruit_item布局加载进行，然后创建一个ViewHolder实例，并把加载出来的布局传入到构造函数中，最后将ViewHolder的实例返回。     * onBindViewHolder():用于对RecyclerView子项的数据进行赋值的，会在每个子项被滚动到屏幕内的时候执行，position指的是当前Fruit实例的位置，然后再将数据设置到ViewHolder的imageview和textView当中即可。     * getItemCount():返回数据源长度，用于告诉RecyclerView一共有多少个子项。     *     */    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item, parent, false);        ViewHolder holder = new ViewHolder(view);        return holder;    }    @Override    public void onBindViewHolder(ViewHolder holder, int position) {        Fruit fruit = mFruitList.get(position);        holder.fruitImage.setImageResource(fruit.getImageId());        holder.fruitName.setText(fruit.getName());    }    @Override    public int getItemCount() {        return mFruitList.size();    }}

4、MainActivity显示瀑布流页的代码

package com.mycompany.waterfallviewtest;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.List;import java.util.Random;public class MainActivity extends AppCompatActivity {    private List<Fruit> fruitList = new ArrayList<>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initFruits();        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycle_view);        /**         * StaggeredGridLayoutManager;         * 概述：实现瀑布流的函数         * 第一个参数：用于指定布局的列数，传入几就代表会把布局分为几列         * 第二个参数：用于指定布局的排列方向         */        StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);        recyclerView.setLayoutManager(layoutManager);        FruitAdapter adapter = new FruitAdapter(fruitList);        recyclerView.setAdapter(adapter);    }    private void initFruits() {        for (int i = 0;i < 2; i++) {            Fruit apple = new Fruit(getRandomLengthName("Apple"), R.mipmap.ic_launcher);            fruitList.add(apple);            Fruit b = new Fruit(getRandomLengthName("bbbb"), R.mipmap.ic_launcher);            fruitList.add(b);            Fruit c = new Fruit(getRandomLengthName("cccc"), R.mipmap.ic_launcher);            fruitList.add(c);            Fruit d = new Fruit(getRandomLengthName("dddd"), R.mipmap.ic_launcher);            fruitList.add(d);            Fruit e = new Fruit(getRandomLengthName("eeee"), R.mipmap.ic_launcher);            fruitList.add(e);            Fruit f = new Fruit(getRandomLengthName("fffff"), R.mipmap.ic_launcher);            fruitList.add(f);            Fruit g = new Fruit(getRandomLengthName("gggg"), R.mipmap.ic_launcher);            fruitList.add(g);            Fruit h = new Fruit(getRandomLengthName("hhhh"), R.mipmap.ic_launcher);            fruitList.add(h);            Fruit l = new Fruit(getRandomLengthName("llll"), R.mipmap.ic_launcher);            fruitList.add(b);        }    }    private String getRandomLengthName(String name) {        Random random = new Random();        int length = random.nextInt(20)+1;        StringBuilder builder = new StringBuilder();        for (int i = 0 ;i < length; i++) {            builder.append(name);        }        return builder.toString();    }}

5、activity_main.xml中代码

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView        android:id="@+id/recycle_view"        android:layout_width="match_parent"        android:layout_height="match_parent" /></LinearLayout>