Android学习--RecyclerView的使用

RecyclerView可以说是一个增强版的ListView

使用他之前我们需要在项目的build.gradle中添加相应的依赖库才可以

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:recyclerview-v7:24.2.1'
}

然后我们也需要准备一个实体类，和一个行布局，这里以一个水果类举例

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 void setName(String name) {
        this.name = name;
    }

    public int getImageId() {
        return imageId;
    }

    public void setImageId(int imageId) {
        this.imageId = imageId;
    }
}

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

    <ImageView
        android:id="@+id/fruit_image"
        android:src="@mipmap/ic_launcher"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
       />
    <TextView
        android:id="@+id/fruit_name"
        android:text="苹果"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        android:layout_marginLeft="15dp"/>

</LinearLayout>

然后我们需要准备一个适配器

public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder> {
    private List<Fruit> mFruitList;

    public FruitAdapter(List<Fruit> FruitList){
        mFruitList=FruitList;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item,parent,false);
        final ViewHolder holder=new ViewHolder(view);
        holder.fruitView.setOnClickListener(new View.OnClickListener() {//点击事件
            @Override
            public void onClick(View v) {
                int position=holder.getAdapterPosition();//获取用户点击的position
                Fruit fruit=mFruitList.get(position);
                Toast.makeText(v.getContext(),fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        holder.fruitImage.setOnClickListener(new View.OnClickListener() {//点击事件

            @Override
            public void onClick(View v) {
                int position=holder.getAdapterPosition();//获取用户点击的position
                Fruit fruit=mFruitList.get(position);
                Toast.makeText(v.getContext(),fruit.getImageId(),Toast.LENGTH_SHORT).show();
            }
        });

        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();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        View fruitView;//fruitView变量来保存子项最外层布局的实例
        ImageView fruitImage;
        TextView fruitName;
        public ViewHolder(View itemView) {
            super(itemView);
            fruitView=itemView;
            fruitImage= (ImageView) itemView.findViewById(R.id.fruit_image);
            fruitName= (TextView) itemView.findViewById(R.id.fruit_name);
        }
    }
}

然后在mainActivity中运用

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);
       //LinearLayoutManager layoutmanager=new LinearLayoutManager(this);//指定RecyclerView的布局方式
//       layoutmanager.setOrientation(LinearLayoutManager.HORIZONTAL);//设置布局的排列方向
        /*
        第一个参数：指定布局的列数，传入3，则表示会把布局分为3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("苹果",R.drawable.xiaoniao);
            fruitList.add(apple);
            Fruit banana=new Fruit("香蕉",R.drawable.xiaoniao);
            fruitList.add(banana);
            Fruit orange=new Fruit("橘子",R.drawable.xiaoniao);
            fruitList.add(orange);
            Fruit watermelon=new Fruit("西瓜",R.drawable.xiaoniao);
            fruitList.add(watermelon);
            Fruit pear=new Fruit("梨",R.drawable.xiaoniao);
            fruitList.add(pear);
            Fruit strawberry=new Fruit("草莓",R.drawable.xiaoniao);
            fruitList.add(strawberry);
        }
    }

}