Android RecyclerView（二）实现横向滚动和瀑布流布局_android recyclerview 横向 瀑布流 csdn

项目完整代码
https://github.com/Phil-tom/Android-The-First-Line-of-Code/tree/main/Chapter3/RecyclerViewTest

RecyclerView实现横向滚动

ListView做不到横向滚动，RecyclerView可以。
fruit_item.xml需要修改，在之前纵向滚动的时候，该布局里面的元素是水平排列的。如果实现横向滚动的话，该布局里面的元素应该纵向排列。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="100dp"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" /><!--设置在布局中水平居中-->
    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="10dp" /><!--让文字和图片保持一定距离-->
</LinearLayout>
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修改MainActivity.java的代码
添加一行
layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initFruits();//初始化水果数据
    RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
    LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
    recyclerView.setLayoutManager(layoutManager);
    FruitAdapter adapter = new FruitAdapter(fruitList);
    recyclerView.setAdapter(adapter);
}
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瀑布流布局

修改fruit_item.xml
TextView的对齐属性改成了居左对齐，因为之后展示的文字长度偏长

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" /><!--设置在布局中水平居中-->
    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
        android:layout_marginTop="10dp" /><!--让文字和图片保持一定距离-->
</LinearLayout>
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修改MainActivity.java
StaggeredGridLayoutManager的构造方法接受两个参数，第一个参数用于指定布局的列数，传入3表示会把布局分成3列；第二个参数用于指定布局的排列方向

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();//初始化水果数据
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
    
        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.drawable.apple_pic);
            fruitList.add(apple);
            Fruit banana = new Fruit(getRandomLengthName("Banana"), R.drawable.banana_pic);
            fruitList.add(banana);
            Fruit orange = new Fruit(getRandomLengthName("Orange"), R.drawable.orange_pic);
            fruitList.add(orange);
            Fruit watermelon = new Fruit(getRandomLengthName("Watermelon"), R.drawable.watermelon_pic);
            fruitList.add(watermelon);
            Fruit pear = new Fruit(getRandomLengthName("Pear"), R.drawable.pear_pic);
            fruitList.add(pear);
            Fruit pineapple = new Fruit(getRandomLengthName("Pineapple"), R.drawable.pineapple_pic);
            fruitList.add(pineapple);
            Fruit strawberry = new Fruit(getRandomLengthName("Strawberry"), R.drawable.strawberry_pic);
            fruitList.add(strawberry);
            Fruit cherry = new Fruit(getRandomLengthName("cherry"), R.drawable.cherry_pic);
            fruitList.add(cherry);
            Fruit mango = new Fruit(getRandomLengthName("Mango"), R.drawable.mango_pic);
            fruitList.add(mango);
    
        }
    
    }
    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();
    }
}
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