为什么RecyclerView没有 onItemClickListener
该RecyclerView是一个工具箱，在旧的对比ListView它在功能和更大的灵活性，更低的构建。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将它扩展到您喜欢的程度，在正确的地方它的功能要强大得多；）。
在我看来，最复杂的功能RecyclerView是快速滚动。其他大多数功能都可以轻松实现。
如果您想了解其他很酷的功能，RecyclerView增加阅读这个回答另一个问题。
高效内存-onItemClickListener的嵌入式解决方案
该解决方案已经提出由乌戈·维瑟，一个Android GDE，之后RecyclerView被释放。他为您提供了一个无许可证的类，供您放入代码并使用它。
它展示了RecyclerView通过使用引入的一些多功能性RecyclerView.OnChildAttachStateChangeListener。
编辑2019：我的Java Kotlin版本，来自Hugo Visser的Java之一，保留在下面
Kotlin / 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>
然后将以下代码添加到您的源代码中
科特林
用法：
recyclerView.onItemClick { recyclerView, position, v ->
// do it
}
（它还支持长按一下项目，并在下面查看我添加的另一项功能）。
实现（我对Hugo Visser Java代码的适应）：
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) }
}
（参见下文，您还需要添加一个XML文件）
Kotlin版本的奖励功能
有时您不希望RecyclerView的所有项目都可单击。
为了解决这个问题，我介绍了ItemClickSupportViewHolder可用于ViewHolder控制可单击项的界面。
例：
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
}
});
（它还支持长按项目）
实施（我补充的评论）：
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);
}
}
工作原理（为什么效率很高）
这个类的工作通过附加RecyclerView.OnChildAttachStateChangeListener的RecyclerView。每当有孩子与之分离或分离时，都会通知此侦听器RecyclerView。代码使用此代码将点击/长按侦听器附加到视图。这听众问RecyclerView了RecyclerView.ViewHolder其中包含的位置。
这比其他解决方案更有效，因为它避免了为每个视图创建多个侦听器，并RecyclerView在滚动视图时不断销毁并创建它们。
如果需要更多代码，您还可以修改代码以将持有人本身还给您。
最后的话
请记住，通过在列表的每个视图上设置单击侦听器（如建议的其他答案），完全可以在适配器中进行处理。
这不是最有效的方法（每次重用视图时都创建一个新的侦听器），但是它可以工作，并且在大多数情况下这不是问题。
这也不利于关注点分离，因为委托单击事件并不是真正的适配器工作。