[Android]RecyclerView基本使用+adapter回调接口实现点击事件

阅读原文时间：2021年04月20日阅读：1

一、概述

RrcyclerView是ListView的加强版，不仅可以轻松实现和ListView同样的效果，还优化了ListView中存在的各种不同之处。

Android官方推荐我们使用RecyclerView。

二、基本用法

1.首先需要在项目的build.gradle中添加相应的依赖库：

implementation 'com.android.support:recyclerview-v7:27.1.1'

2.在layout布局中添加RecyclerView空间：activity_list_view.xml

<?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">

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

</LinearLayout>

3.新建Adapter适配器：FruitRecyclerAdapter.java

public class FruitRecyclerAdapter extends RecyclerView.Adapter<FruitRecyclerAdapter.ViewHolder> {

    //数据源
    private List<Fruit> mFruitList;

    public FruitRecyclerAdapter(List<Fruit> mFruitList) {
        this.mFruitList = mFruitList;
    }

    //自定义内部类 ViewHolder
    public static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView fruitImage;
        TextView fruitName;
        Button button;
        LinearLayout itemDetail;

        public ViewHolder(View itemView) {
            super(itemView);
            fruitImage = (ImageView) itemView.findViewById(R.id.fruit_image);
            fruitName = (TextView) itemView.findViewById(R.id.fruit_name);
            button = (Button) itemView.findViewById(R.id.fruit_button);
            itemDetail = (LinearLayout) itemView.findViewById(R.id.item_detail);
        }
    }

    //用于创建ViewHolder实例，并加载布局
    @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;
    }

    //对RecyclerView子项数据进行赋值
    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        Fruit fruit = mFruitList.get(position);
        holder.fruitImage.setImageResource(fruit.getImageId());
        holder.fruitName.setText(fruit.getName());
    }

    //RecyclerView子项的个数
    @Override
    public int getItemCount() {
        return mFruitList.size();
    }
}

4. 新建item子布局layout：fruit_item.xml

新建适配器类要继承RecyclerView.Adapter<…>，继承的泛型ViewHolder需要我们自己新建内部类ViewHolder。
内部类ViewHolder,继承RecyclerView.ViewHolder。
新建构造函数，初始化数据源list。

因为继承了RecyclerView.Adapter,所以要重写onCreateViewHolder()、onBindViewHolder()、getItemCount()三个方法。

<ImageView
    android:id="@+id/fruit_image"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

<Button
    android:id="@+id/fruit_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="点击" />

<TextView
    android:id="@+id/fruit_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:layout_marginStart="10dp" />

5.activity对RecyclerView的处理：

    recyclerView = (RecyclerView) findViewById(R.id.recycle_view);
    LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
    recyclerView.setLayoutManager(layoutManager);
    adapter = new FruitRecyclerAdapter(fruitList);
    recyclerView.setAdapter(adapter);

layoutmanager用于指定RecyclerView的布局方式：

LinearLayoutManager.VERTICAL ：线性垂直
LinearLayoutManager.HORIZONTAL：线性水平
GridLayoutManager.VERTICAL ：网格垂直
GridLayoutManager.HORIZONTAL：网格水平
StaggeredGridLayoutManager.VERTICAL：瀑布流

获取adapter实例，并传入数据源list。最后调用RecyclerView的setAdapter()方法。

到此RecyclerView和数据之间的关联就建立好了。

三、添加点击事件

大多数情况下，我们需要实现每个item本身或者item中的button等控件的点击事件。就需要在adapter中用到接口回调，

添加了接口回调的adapter代码如下：

public class FruitRecyclerAdapter extends RecyclerView.Adapter<FruitRecyclerAdapter.ViewHolder> {

    //数据源
    private List<Fruit> mFruitList;
    //接口
    private ClickInterface clickInterface;

    public FruitRecyclerAdapter(List<Fruit> mFruitList) {
        this.mFruitList = mFruitList;
    }

    //--------------------点击事件-------------------------------------------//
    public void setOnclick(ClickInterface clickInterface) {
        this.clickInterface = clickInterface;
    }

    //回调接口
    public interface ClickInterface {
        void onButtonClick(View view, int position);

        void onItemClick(View view, int position);
    }
    //--------------------点击事件-------------------------------------------//

    //自定义内部类 ViewHolder
    public static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView fruitImage;
        TextView fruitName;
        Button button;
        LinearLayout itemDetail;

        public ViewHolder(View itemView) {
            super(itemView);
            fruitImage = (ImageView) itemView.findViewById(R.id.fruit_image);
            fruitName = (TextView) itemView.findViewById(R.id.fruit_name);
            button = (Button) itemView.findViewById(R.id.fruit_button);
            itemDetail = (LinearLayout) itemView.findViewById(R.id.item_detail);
        }
    }

    //用于创建ViewHolder实例，并加载布局
    @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;
    }

    //对RecyclerView子项数据进行赋值
    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        Fruit fruit = mFruitList.get(position);
        holder.fruitImage.setImageResource(fruit.getImageId());
        holder.fruitName.setText(fruit.getName());

        //--------------------点击事件-------------------------------------------//
        //Button点击事件
        holder.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (clickInterface != null) {
                    clickInterface.onButtonClick(v, position);
                }
            }
        });
        //item点击事件
        holder.itemDetail.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (clickInterface != null) {
                    clickInterface.onItemClick(v, position);
                }
            }
        });
        //--------------------点击事件-------------------------------------------//
    }

    //RecyclerView子项的个数
    @Override
    public int getItemCount() {
        return mFruitList.size();
    }
}

Activity代码中的点击事件处理：

        recyclerView = (RecyclerView) findViewById(R.id.recycle_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(layoutManager);
        adapter = new FruitRecyclerAdapter(fruitList);
        recyclerView.setAdapter(adapter);

        //添加点击事件
        recyclerView.post(new Runnable() {
            @Override
            public void run() {
                adapter.setOnclick(new FruitRecyclerAdapter.ClickInterface() {
                    @Override
                    public void onButtonClick(View view, int position) {
                        Toast.makeText(view.getContext(), "Click Button - position: " + position + "   name: " + fruitList.get(position).getName(), Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onItemClick(View view, int position) {
                        Toast.makeText(view.getContext(), "Click Item Detail - position: " + position + "   name: " + fruitList.get(position).getName(), Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });

这里实现了item和button的两个点击事件。

END.

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