为什么在 RecyclerView.Adapter 的 onBindViewHolder 中添加 OnClickListener 被认为是不好的做法? [英] Why is adding an OnClickListener inside onBindViewHolder of a RecyclerView.Adapter considered bad practice?

问题描述

我有以下用于 RecyclerView.Adapter 类的代码，它工作正常:

I have the following code for a RecyclerView.Adapter class and it works fine:

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.Viewholder> {

    private List<Information> items;
    private int itemLayout;

    public MyAdapter(List<Information> items, int itemLayout){
        this.items = items;
        this.itemLayout = itemLayout;
    }

    @Override
    public Viewholder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(itemLayout, parent, false);
        return new Viewholder(v);
    }

    @Override
    public void onBindViewHolder(Viewholder holder, final int position) {
        Information item = items.get(position);
        holder.textView1.setText(item.Title);
        holder.textView2.setText(item.Date);

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(view.getContext(), "Recycle Click" + position, Toast.LENGTH_SHORT).show();
            }
        });

       holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
       @Override
       public boolean onLongClick(View v) {
          Toast.makeText(v.getContext(), "Recycle Click" + position, Toast.LENGTH_SHORT).show();
           return true;
       }
});
    }

    @Override
    public int getItemCount() {
        return items.size();
    }

    public class Viewholder extends RecyclerView.ViewHolder {
        public  TextView textView1;
        public TextView textView2;

        public Viewholder(View itemView) {
            super(itemView);
            textView1=(TextView) itemView.findViewById(R.id.text1);
            textView2 = (TextView) itemView.findViewById(R.id.date_row);

        }
    }
}

但是，我认为在 onBindViewHolder 方法中实现 OnClickListener 是不好的做法.为什么这是不好的做法，还有什么更好的选择?

However, I believe it is bad practice to implement the OnClickListener in the onBindViewHolder method. Why is this bad practice, and what is a better alternative?

推荐答案

最好在 ViewHolder 内处理点击逻辑的原因是它允许更明确的点击侦听器.正如 Commonsware 书中所述:

The reason it is better to handle your click logic inside the ViewHolder is because it allows for more explicit click listeners. As expressed in the Commonsware book:

ListView 行中的可点击小部件，如 RatingBar，长期以来一直与行本身的点击事件发生冲突.获取可以点击的行，以及也可以点击的行内容，有时会变得有点棘手.使用 RecyclerView，您可以更明确地控制此类事情的处理方式……因为您是设置所有点击处理逻辑的人.

Clickable widgets, like a RatingBar, in a ListView row had long been in conflict with click events on rows themselves. Getting rows that can be clicked, with row contents that can also be clicked, gets a bit tricky at times. With RecyclerView, you are in more explicit control over how this sort of thing gets handled… because you are the one setting up all of the on-click handling logic.

通过使用 ViewHolder 模型，您可以在 RecyclerView 中获得比以前在 ListView 中处理点击更多的好处.我在一篇比较差异的博客文章中写到了这一点 - https://androidessence.com/recyclerview-vs-listview

By using the ViewHolder model you can gain a lot of benefits for click handling in a RecyclerView than previously in the ListView. I wrote about this in a blog post comparing the differences - https://androidessence.com/recyclerview-vs-listview

至于为什么在 ViewHolder 中而不是在 onBindViewHolder() 中更好，那是因为 onBindViewHolder() 为每个项目调用并设置点击当您可以在 ViewHolder 构造函数中调用一次 listener 时，listener 是不必要的重复选项.然后，如果您的点击响应取决于所点击项目的位置，您可以简单地从 ViewHolder 中调用 getAdapterPosition().这里是我给出的另一个答案，演示了如何使用OnClickListener 来自您的 ViewHolder 类.

As for why it is better in the ViewHolder instead of in onBindViewHolder(), that is because onBindViewHolder() is called for each and every item and setting the click listener is an unnecessary option to repeat when you can call it once in your ViewHolder constructor. Then, if your click responds depends on the position of the item clicked, you can simply call getAdapterPosition() from within the ViewHolder. Here is another answer I've given that demonstrates how you can use the OnClickListener from within your ViewHolder class.

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