为什么 RecyclerView 没有onItemClickListener
这RecyclerView是一个工具箱，与旧的相比，ListView它具有更少的内置功能和更大的灵活性。这onItemClickListener不是从 ListView 中删除的唯一功能。但是它有很多听众和方法可以根据你的喜好扩展它，它在右手中要强大得多；）。
在我看来，删除的最复杂的功能RecyclerView是Fast Scroll。大多数其他功能都可以轻松地重新实现。
如果您想知道RecyclerView添加了哪些其他很酷的功能，请阅读另一个问题的答案。
内存高效 - onItemClickListener 的插入式解决方案
这个解决方案是由Android GDE的Hugo Visser在发布后提出的。他为您提供了一个免许可证课程，您只需放入您的代码并使用它。RecyclerView
它展示了RecyclerView通过使用RecyclerView.OnChildAttachStateChangeListener.
编辑 2019：我的 kotlin 版本，java 版本，来自 Hugo Visser，保留在下面
科特林/Java
创建一个文件values/ids.xml并将其放入其中：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="item_click_support" type="id" />
</resources>
然后将下面的代码添加到您的源
科特林
用法：
recyclerView.onItemClick { recyclerView, position, v ->
// do it
}
（它还支持长项目点击，我添加的另一个功能见下文）。
实现（我对 Hugo Visser Java 代码的改编）：
typealias OnRecyclerViewItemClickListener = (recyclerView: RecyclerView, position: Int, v: View) -> Unit
typealias OnRecyclerViewItemLongClickListener = (recyclerView: RecyclerView, position: Int, v: View) -> Boolean
class ItemClickSupport private constructor(private val recyclerView: RecyclerView) {
private var onItemClickListener: OnRecyclerViewItemClickListener? = null
private var onItemLongClickListener: OnRecyclerViewItemLongClickListener? = null
private val attachListener: RecyclerView.OnChildAttachStateChangeListener = object : RecyclerView.OnChildAttachStateChangeListener {
override fun onChildViewAttachedToWindow(view: View) {
// every time a new child view is attached add click listeners to it
val holder = this@ItemClickSupport.recyclerView.getChildViewHolder(view)
.takeIf { it is ItemClickSupportViewHolder } as? ItemClickSupportViewHolder
if (onItemClickListener != null && holder?.isClickable != false) {
view.setOnClickListener(onClickListener)
}
if (onItemLongClickListener != null && holder?.isLongClickable != false) {
view.setOnLongClickListener(onLongClickListener)
}
}
override fun onChildViewDetachedFromWindow(view: View) {
}
}
init {
// the ID must be declared in XML, used to avoid
// replacing the ItemClickSupport without removing
// the old one from the RecyclerView
this.recyclerView.setTag(R.id.item_click_support, this)
this.recyclerView.addOnChildAttachStateChangeListener(attachListener)
}
companion object {
fun addTo(view: RecyclerView): ItemClickSupport {
// if there's already an ItemClickSupport attached
// to this RecyclerView do not replace it, use it
var support: ItemClickSupport? = view.getTag(R.id.item_click_support) as? ItemClickSupport
if (support == null) {
support = ItemClickSupport(view)
}
return support
}
fun removeFrom(view: RecyclerView): ItemClickSupport? {
val support = view.getTag(R.id.item_click_support) as? ItemClickSupport
support?.detach(view)
return support
}
}
private val onClickListener = View.OnClickListener { v ->
val listener = onItemClickListener ?: return@OnClickListener
// ask the RecyclerView for the viewHolder of this view.
// then use it to get the position for the adapter
val holder = this.recyclerView.getChildViewHolder(v)
listener.invoke(this.recyclerView, holder.adapterPosition, v)
}
private val onLongClickListener = View.OnLongClickListener { v ->
val listener = onItemLongClickListener ?: return@OnLongClickListener false
val holder = this.recyclerView.getChildViewHolder(v)
return@OnLongClickListener listener.invoke(this.recyclerView, holder.adapterPosition, v)
}
private fun detach(view: RecyclerView) {
view.removeOnChildAttachStateChangeListener(attachListener)
view.setTag(R.id.item_click_support, null)
}
fun onItemClick(listener: OnRecyclerViewItemClickListener?): ItemClickSupport {
onItemClickListener = listener
return this
}
fun onItemLongClick(listener: OnRecyclerViewItemLongClickListener?): ItemClickSupport {
onItemLongClickListener = listener
return this
}
}
/** Give click-ability and long-click-ability control to the ViewHolder */
interface ItemClickSupportViewHolder {
val isClickable: Boolean get() = true
val isLongClickable: Boolean get() = true
}
// Extension function
fun RecyclerView.addItemClickSupport(configuration: ItemClickSupport.() -> Unit = {}) = ItemClickSupport.addTo(this).apply(configuration)
fun RecyclerView.removeItemClickSupport() = ItemClickSupport.removeFrom(this)
fun RecyclerView.onItemClick(onClick: OnRecyclerViewItemClickListener) {
addItemClickSupport { onItemClick(onClick) }
}
fun RecyclerView.onItemLongClick(onLongClick: OnRecyclerViewItemLongClickListener) {
addItemClickSupport { onItemLongClick(onLongClick) }
}
（请记住，您还需要添加一个 XML 文件，请参阅本节上方）
Kotlin 版本的额外功能
有时您不希望 RecyclerView 的所有项目都是可点击的。
为了解决这个问题，我介绍了ItemClickSupportViewHolder您可以ViewHolder用来控制可点击项目的界面。
例子：
class MyViewHolder(view): RecyclerView.ViewHolder(view), ItemClickSupportViewHolder {
override val isClickable: Boolean get() = false
override val isLongClickable: Boolean get() = false
}
爪哇
用法：
ItemClickSupport.addTo(mRecyclerView)
.setOnItemClickListener(new ItemClickSupport.OnItemClickListener() {
@Override
public void onItemClicked(RecyclerView recyclerView, int position, View v) {
// do it
}
});
（它也支持长项目点击）
实施（我添加的评论）：
public class ItemClickSupport {
private final RecyclerView mRecyclerView;
private OnItemClickListener mOnItemClickListener;
private OnItemLongClickListener mOnItemLongClickListener;
private View.OnClickListener mOnClickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
// ask the RecyclerView for the viewHolder of this view.
// then use it to get the position for the adapter
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
mOnItemClickListener.onItemClicked(mRecyclerView, holder.getAdapterPosition(), v);
}
}
};
private View.OnLongClickListener mOnLongClickListener = new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnItemLongClickListener != null) {
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
return mOnItemLongClickListener.onItemLongClicked(mRecyclerView, holder.getAdapterPosition(), v);
}
return false;
}
};
private RecyclerView.OnChildAttachStateChangeListener mAttachListener
= new RecyclerView.OnChildAttachStateChangeListener() {
@Override
public void onChildViewAttachedToWindow(View view) {
// every time a new child view is attached add click listeners to it
if (mOnItemClickListener != null) {
view.setOnClickListener(mOnClickListener);
}
if (mOnItemLongClickListener != null) {
view.setOnLongClickListener(mOnLongClickListener);
}
}
@Override
public void onChildViewDetachedFromWindow(View view) {
}
};
private ItemClickSupport(RecyclerView recyclerView) {
mRecyclerView = recyclerView;
// the ID must be declared in XML, used to avoid
// replacing the ItemClickSupport without removing
// the old one from the RecyclerView
mRecyclerView.setTag(R.id.item_click_support, this);
mRecyclerView.addOnChildAttachStateChangeListener(mAttachListener);
}
public static ItemClickSupport addTo(RecyclerView view) {
// if there's already an ItemClickSupport attached
// to this RecyclerView do not replace it, use it
ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
if (support == null) {
support = new ItemClickSupport(view);
}
return support;
}
public static ItemClickSupport removeFrom(RecyclerView view) {
ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
if (support != null) {
support.detach(view);
}
return support;
}
public ItemClickSupport setOnItemClickListener(OnItemClickListener listener) {
mOnItemClickListener = listener;
return this;
}
public ItemClickSupport setOnItemLongClickListener(OnItemLongClickListener listener) {
mOnItemLongClickListener = listener;
return this;
}
private void detach(RecyclerView view) {
view.removeOnChildAttachStateChangeListener(mAttachListener);
view.setTag(R.id.item_click_support, null);
}
public interface OnItemClickListener {
void onItemClicked(RecyclerView recyclerView, int position, View v);
}
public interface OnItemLongClickListener {
boolean onItemLongClicked(RecyclerView recyclerView, int position, View v);
}
}
它是如何工作的（为什么它是有效的）
此类通过将 a 附加RecyclerView.OnChildAttachStateChangeListener到RecyclerView. 每次有孩子从RecyclerView. 代码使用它来将点击/长按侦听器附加到视图。该听众询问RecyclerView包含RecyclerView.ViewHolder该位置的 。
RecyclerView这比其他解决方案更有效，因为它避免为每个视图创建多个侦听器，并在滚动时不断销毁和创建它们。
如果您需要更多，您还可以调整代码以将持有人返还给您。
最后的评论
请记住，通过在列表的每个视图上设置一个单击侦听器来在适配器中处理它是完全可以的，就像其他建议的答案一样。
这不是最有效的做法（每次重用视图时都会创建一个新的侦听器），但它可以工作，并且在大多数情况下这不是问题。
这也有点反对关注点分离，因为委托点击事件并不是适配器的真正工作。