7. How to add the Click to RecyclerView and LongClick events

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Detailed RecyclerView Series Article Directory

Overview

If you do Android development, then you must have heard that RecyclerView does not provide a default implementation of Click and LongClick events.I don't know what the official intention is, so this course will implement this function. The completed rendering is shown in the following figure:

Here we don't talk about excessive encapsulation, and now we just write it casually, the purpose is to make it easier to understand.A later course on encapsulation will cover further encapsulation.

Add OnItemClickListener

public interface OnItemClickListener {void onItemClick(ViewHolder holder,int position);}

Add an interface to call back to the location you need after the click event in the adapter.

implement the click event in the adapter

public void onBindViewHolder(final CardViewActivity.MyAdapter.MyViewHolder holder,final int position) {String d = CardViewActivity.this.data.get(position);holder.bindData(d, position);if (onItemClickListener != null) {holder.itemView.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {onItemClickListener.onItemClick(holder, position);}});}}

Here we first judge whether the onItemClickListener is empty, and then set the click leave, which saves more resources than setting the click listener as soon as it comes up, and then judging whether the listener is empty in the click event.

handle click event

Then you can handle the click event in the callback method.

String s = data.get(position);Intent intent = new Intent(this, NewsDetailActivity.class);intent.putExtra(NewsDetailActivity.URL, s);startActivity(intent, options.toBundle());

The long press event is also very simple. You can directly change the above listener, add a method, or create an interface. Let's create another interface here.

create OnItemLongClickListener

public interface OnItemLongClickListener {boolean onItemLongClick(ViewHolder holder,int position);}

It is important to note that we passed the ViewHolder in the callback. The advantage of this is that we can get the corresponding view in the click event, and we can directly perform some animations without getting the View again in findViewById.

handle long press event

There is no need to say more about this, everyone basically knows it, but it should be noted that onItemLongClick has a return value, and he judges whether OnItemClick is being called according to the return, so this place must return different values ​​according to the actual situation.

@Overridepublic boolean onItemLongClick(ViewHolder holder, int position) {Toast.makeText(this, "Long Click", Toast.LENGTH_SHORT).show();return true;}