移动技术开发：RecyclerView瀑布流水果列表

1 实验名称

RecyclerView瀑布流水果列表

2 实验目的

掌握RecyclerView控件的实现方法和基本应用

3 实验源代码

布局文件代码：

activity_main：

<?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"><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/recycler_view"android:layout_width="match_parent"android:layout_height="match_parent"/>
</LinearLayout>

fruit_item：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"><ImageViewandroid:id="@+id/fruit_image"android:layout_width="wrap_content"android:layout_height="wrap_content" /><TextViewandroid:id="@+id/fruit_name"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_gravity="center"/>
</LinearLayout>

Java代码：

MainActivity .java：

public class MainActivity extends AppCompatActivity {private List<Fruit> fruitLists = new ArrayList<>();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//初始化水果列表数据initFruits();//创建循环列表对象RecyclerView recycler_view = findViewById(R.id.recycler_view);//创建一个线性布局管理器对象//LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);//设置线性布局管理器的管理方向为水平管理//linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);//设置循环列表的布局管理器//创建一个3列垂直的瀑布流布局管理器对象StaggeredGridLayoutManager staggeredGridLayoutManager =new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);recycler_view.setLayoutManager(staggeredGridLayoutManager);//创建列表数据适配器对象并把数据源关联上FruitAdapter fruitAdapter = new FruitAdapter(fruitLists);//让循环列表使用适配器对象recycler_view.setAdapter(fruitAdapter);}private void initFruits(){for (int i = 0; i < 2; i++) {Fruit apple = new Fruit(getRandomLengthName("Apple"), R.drawable.apple_pic);fruitLists.add(apple);Fruit banana = new Fruit(getRandomLengthName("Banana"), R.drawable.banana_pic);fruitLists.add(banana);Fruit orange = new Fruit(getRandomLengthName("Orange"), R.drawable.orange_pic);fruitLists.add(orange);Fruit watermelon = new Fruit(getRandomLengthName("Watermelon"), R.drawable.watermelon_pic);fruitLists.add(watermelon);Fruit pear = new Fruit(getRandomLengthName("Pear"), R.drawable.pear_pic);fruitLists.add(pear);Fruit grape = new Fruit(getRandomLengthName("Grape"), R.drawable.grape_pic);fruitLists.add(grape);Fruit pineapple = new Fruit(getRandomLengthName("Pineapple"), R.drawable.pineapple_pic);fruitLists.add(pineapple);Fruit strawberry = new Fruit(getRandomLengthName("Strawberry"), R.drawable.strawberry_pic);fruitLists.add(strawberry);Fruit cherry = new Fruit(getRandomLengthName("Cherry"), R.drawable.cherry_pic);fruitLists.add(cherry);Fruit mango = new Fruit(getRandomLengthName("Mango"), R.drawable.mango_pic);fruitLists.add(mango);}}private String getRandomLengthName(String name){Random random = new Random();int length = random.nextInt(20);StringBuilder stringBuilder = new StringBuilder();for(int i=0;i<length;i++){stringBuilder.append(name);}return stringBuilder.toString();}
}

FruitAdapter.java：

public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder> {private List<Fruit> fruitLists = null;//子项水果数据源列表public FruitAdapter(List<Fruit> fruitLists) {this.fruitLists = fruitLists;}@NonNull@Overridepublic ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {//得到子项布局的视图View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item,parent,false);ViewHolder viewHolder = new ViewHolder(itemView);return viewHolder;}@Overridepublic void onBindViewHolder(@NonNull ViewHolder holder, int position) {Fruit fruit = fruitLists.get(position);//根据位置得到一个水果对象//将水果图片放到子项视图持有器的ImageView中holder.fruit_image.setImageResource(fruit.getImageId());//将水果名字放到子项视图持有器的TextView中holder.fruit_name.setText(fruit.getName());}@Overridepublic int getItemCount() {return fruitLists.size();}//列表子项的视图持有器static class ViewHolder extends RecyclerView.ViewHolder{ImageView fruit_image;TextView fruit_name;public ViewHolder(@NonNull View itemView) {super(itemView);fruit_image = itemView.findViewById(R.id.fruit_image);fruit_name = itemView.findViewById(R.id.fruit_name);}}
}

Fruit.java：

//自定义数据源类
public class Fruit {private String name;private int imageId;//水果图片ID号public Fruit(String name, int imageId) {this.name = name;this.imageId = imageId;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getImageId() {return imageId;}public void setImageId(int imageId) {this.imageId = imageId;}
}