recyclerview实践demo，支持item点击事件

背景

项目中之前使用recyclerview较多，简单总结一下，持续优化。

基本使用

话不多说，直接上代码。

1、xml布局文件中个使用recyclerview。

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activity.RecyclerViewActivity">
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

2、activity中使用代码

public class RecyclerViewActivity extends AppCompatActivity {
    RecyclerView recyclerView;
    List<Sample> sampleList = new ArrayList<>();
    int listSize = 100;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recycler_view);

        recyclerView = findViewById(R.id.recyclerView);
        initSampleList();

        ListAdapter listAdapter = new ListAdapter(sampleList, this);
        // 垂直线性布局
//        LinearLayoutManager layoutManager = new LinearLayoutManager(null);
        // 瀑布流布局
        StaggeredGridLayoutManager staggeredGridManager = new StaggeredGridLayoutManager(2, 1);
        // 1、设置adapter
        recyclerView.setAdapter(listAdapter);
        // 2、设置布局
        recyclerView.setLayoutManager(staggeredGridManager);
    }

    private void initSampleList() {
        for (int i = 0; i < listSize; i++) {
            Sample sample = new Sample();
            sample.setIcon(R.drawable.ball);
            sample.setTvName("ball: " + i);
            sample.setTvContent("ball price: " + i * 100);
            sampleList.add(sample);
            Sample sample1 = new Sample();
            sample1.setIcon(R.drawable.tao);
            sample1.setTvName("tao: " + i);
            sample1.setTvContent("tao price: " + i * 100);
            sampleList.add(sample1);
            Sample sample2 = new Sample();
            sample2.setIcon(R.drawable.apple);
            sample2.setTvName("apple: " + i);
            sample2.setTvContent("apple price: " + i * 100);
            sampleList.add(sample2);
        }
    }
}

可以看到，recyclerview使用的关键是设置好对应的adapter。

3、自定义adapter，item监听可以放在ViewHolder中实现

public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ListHolder> {
    List<Sample> sampleList;
    Context context;

    /**
     * 1、定义Adapter首先需要一个ViewHolder
     * 2、实现item监听可以放在ViewHolder中实现
     */
    static class ListHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView tvName;
        TextView tvContent;
        ImageView ivIcon;
        Context context;

        public ListHolder(@NonNull View itemView, Context context) {
            super(itemView);
            tvName = itemView.findViewById(R.id.list_name);
            tvContent = itemView.findViewById(R.id.list_content);
            ivIcon = itemView.findViewById(R.id.list_icon);
            itemView.setOnClickListener(this);
            this.context = context;
        }

        @Override
        public void onClick(View v) {
            Toast.makeText(context, getAdapterPosition() + "", Toast.LENGTH_SHORT).show();
        }

        /**
         * 给每个控件设置对应的数据
         */
        public void setData(Sample sample) {
            tvContent.setText(sample.getTvContent());
            tvName.setText(sample.getTvName());
            ivIcon.setImageResource(sample.getIcon());
        }
    }

    /**
     * 构造函数
     */
    public ListAdapter(List<Sample> sampleList, Context context) {
        this.sampleList = sampleList;
        this.context = context;
    }

    /**
     * ViewHolder 首先用inflate方法解析布局，把整个布局传入，再通过ViewHolder把这个布局里的每个控件设置进来
     */
    @NonNull
    @Override
    public ListHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View sampler = View.inflate(parent.getContext(), R.layout.layout_list,null);
        return new ListHolder(sampler, context);
    }

    @Override
    public void onBindViewHolder(@NonNull ListHolder holder, int position) {
        holder.setData(sampleList.get(position));
    }

    @Override
    public int getItemCount() {
        if (sampleList != null) {
            return sampleList.size();
        }
        return 0;
    }
}

adapter中实现item的点击事件，是通过自定义ViewHolder实现的监听事件接口，对比看的话这是一种比较优雅的实现方案。 实现效果如下：