RecyclerView itemClickListener in Kotlin
In case anyone is looking for a more no-frills answer, I tried the following - which is very similar to the solution from AfzalivE:
In my Adapter class I passed the clickListener
as a parameter. On onBindViewHolder
, I've used setOnClickListener
to call clickListener
and handle click event.
MyAdapter.kt:
class MyAdapter constructor(objects: ArrayList<MyObject>, val clickListener: (MyObject) -> Unit) : RecyclerView.Adapter<MyAdapter.Holder>() {
private var mObjects : ArrayList<MyObject> = ArrayList<MyObject>()
init {
mObjects = objects
}
override fun onBindViewHolder(holder: Holder?, position: Int) {
var item : MyObject = objects[position]
// Calling the clickListener sent by the constructor
holder?.containerView?.setOnClickListener { clickListener(item) }
}
// More code (ViewHolder definitions and stuff)...
}
Note: I needed a reference from my list item's container (the root view), which in this case is containerView
Then I passed my object as parameter without need for searching it on a list again and handle it directly on my Activity
class, in the moment I set the adapter:
MyActivity.kt:
myRecyclerView?.adapter = MyAdapter(mObjects) {
Log.e("Activity", "Clicked on item ${it.itemName}")
}
Update
If you need to get the position of the clicked item, just define it as parameter on the callback and then send it back later. Notice the val clickListener: (MyObject, Int) -> Unit
below:
MyAdapter.kt
class MyAdapter constructor(objects: ArrayList<MyObject>, val clickListener: (MyObject, Int) -> Unit) : RecyclerView.Adapter<MyAdapter.Holder>() {
// Rest of the code...
Then on onBindViewHolder()
you pass the position when calling the callback method:
override fun onBindViewHolder(holder: Holder?, position: Int) {
var item : MyObject = objects[position]
// Calling the clickListener sent by the constructor
holder?.containerView?.setOnClickListener { clickListener(item, position) }
}
And on MyActivity.kt, you'll have to change the way you set the adapter so you can get the position. Like this:
myRecyclerView?.adapter = MyAdapter(mObjects) { itemDto: MyObject, position: Int ->
Log.e("MyActivity", "Clicked on item ${itemDto.someItemPropertyLikeName} at position $position")
}
I have a little bit different approach. You can create an extension for your ViewHolder
fun <T : RecyclerView.ViewHolder> T.listen(event: (position: Int, type: Int) -> Unit): T {
itemView.setOnClickListener {
event.invoke(getAdapterPosition(), getItemViewType())
}
return this
}
Then use it in adapter like this
class MyAdapter : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
val items: MutableList<String> = arrayListOf()
override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): MyViewHolder? {
val inflater = LayoutInflater.from(parent!!.getContext())
val view = inflater.inflate(R.layout.item_view, parent, false)
return MyViewHolder(view).listen { pos, type ->
val item = items.get(pos)
//TODO do other stuff here
}
}
override fun onBindViewHolder(holder: MyViewHolder?, position: Int) {
}
override fun getItemCount(): Int {
return items.size()
}
class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {
}
}
I am working with my colleagues on library providing such extensions.
Sorry for the delay, Got an awesome answer from this link and it was in Java.. Did some Homework and converted it to Kotlin..
Now it is working Properly.. Here is the Code,
Create a class named RecyclerItemClickListenr,
class RecyclerItemClickListenr(context: Context, recyclerView: RecyclerView, private val mListener: OnItemClickListener?) : RecyclerView.OnItemTouchListener {
private val mGestureDetector: GestureDetector
interface OnItemClickListener {
fun onItemClick(view: View, position: Int)
fun onItemLongClick(view: View?, position: Int)
}
init {
mGestureDetector = GestureDetector(context, object : GestureDetector.SimpleOnGestureListener() {
override fun onSingleTapUp(e: MotionEvent): Boolean {
return true
}
override fun onLongPress(e: MotionEvent) {
val childView = recyclerView.findChildViewUnder(e.x, e.y)
if (childView != null && mListener != null) {
mListener.onItemLongClick(childView, recyclerView.getChildAdapterPosition(childView))
}
}
})
}
override fun onInterceptTouchEvent(view: RecyclerView, e: MotionEvent): Boolean {
val childView = view.findChildViewUnder(e.x, e.y)
if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {
mListener.onItemClick(childView, view.getChildAdapterPosition(childView))
}
return false
}
override fun onTouchEvent(view: RecyclerView, motionEvent: MotionEvent) {}
override fun onRequestDisallowInterceptTouchEvent(disallowIntercept: Boolean) {}}
and access it from Activity/Fragment as
recyclerView.addOnItemTouchListener(RecyclerItemClickListenr(this, recyclerView, object : RecyclerItemClickListenr.OnItemClickListener {
override fun onItemClick(view: View, position: Int) {
//do your work here..
}
override fun onItemLongClick(view: View?, position: Int) {
TODO("do nothing")
}
}))
My solution is like a combination of the previous ones with a super clean call from the activity.
ContactAdapter:
class ContactAdapter @Inject constructor() : RecyclerView.Adapter<ContactAdapter.ViewHolder>() {
var onItemClick: ((Contact) -> Unit)? = null
var contacts: List<Contact> = emptyList()
...
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val contact = contacts[position]
holder.email.text = contact.email
}
inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val email: TextView = itemView.email
init {
itemView.setOnClickListener {
onItemClick?.invoke(contacts[adapterPosition])
}
}
}
}
ContactActivity:
override fun setupRecyclerAdapter() {
recyclerView.adapter = contactAdapter
recyclerView.layoutManager = LinearLayoutManager(this)
contactAdapter.onItemClick = { contact ->
// do something with your item
Log.d("TAG", contact.email)
}
}