[Android]RecyclerView基本使用+adapter回调接口实现点击事件
16lz
2021-01-23
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"?> 3.新建Adapter适配器：FruitRecyclerAdapter.java
public class FruitRecyclerAdapter extends RecyclerView.Adapter { //数据源 private List mFruitList; public FruitRecyclerAdapter(List 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。
<?xml version="1.0" encoding="utf-8"?> 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 { //数据源 private List mFruitList; //接口 private ClickInterface clickInterface; public FruitRecyclerAdapter(List 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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