I have a RecyclerView with a checkbox for every item. When checkbox pressed it is moved to the bottom of the list. When i check any item besides the first one everything is OK but if i check the first one, it auto-scroll to the new item location.
I redesigned the adapter using a recent codelab but still the same issue
class ItemsAdapter(val clickListener: ItemAdapterListener):
ListAdapter<UiQueryItem<Item>, ItemsAdapter.ViewHolder>(asyncDifferConfig) {
companion object {
private val diffCallback = object : UiQueryItemDiffCallback<Item>() {}
private val executors = AppExecutors()
private val asyncDifferConfig =
AsyncDifferConfig.Builder<UiQueryItem<Item>>(diffCallback)
.setBackgroundThreadExecutor(executors.cpuExecutorService)
.build()
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val item = getItem(position)
holder.bind(item,clickListener)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder.from(parent)
}
class ViewHolder private constructor(val binding: ListItemBinding): RecyclerView.ViewHolder(binding.root){
fun bind(item: UiQueryItem<Item>, clickListener: ItemAdapterListener) {
binding.item = item.item
binding.clickListener = clickListener
binding.isSelected = item.isFlag1
binding.executePendingBindings()
}
companion object {
fun from(parent: ViewGroup): ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val binding = ListItemBinding.inflate(layoutInflater, parent, false)
return ViewHolder(binding)
}
}
}
}
I think i found a workaround.
I noticed the next github issue solution:
Automatic scrolling when new data set #224
It did not work in my case but after tweaking a bit i found an answer. Please note that it is only a workaround and might make some bugs if you are trying to implement your own auto-scroll solution. The Workaround simply checkes if an item changed position from first place and if so, gets back to first position
Also note that #elihart is suggesting other solutions (check the link)
private val dataObserver = object : RecyclerView.AdapterDataObserver() {
override fun onItemRangeMoved(fromPosition: Int, toPosition: Int, itemCount: Int) {
super.onItemRangeMoved(fromPosition, toPosition, itemCount)
if (fromPosition == 0) {
binding.itemRv.scrollToPosition(0)
}
}
}
override fun onResume() {
super.onResume()
adapter.registerAdapterDataObserver(dataObserver)
}
override fun onPause() {
super.onPause()
adapter.unregisterAdapterDataObserver(dataObserver)
}
Related
I have a RecyclerView list, I want the color of the clicked item to be changed. But whenever I am clicking an item the RecyclerView items change randomly.
I have also taken a boolean in my data class to keep track of item selection.
data class
data class OrderAvailableDaysResponseItem(
val actual_date: String,
val day_name: String,
val date_name: String,
val day_num: Int,
// For item selection
var isDateSelected: Boolean)
Inside my fragment, checking if the clicked item matches the list item and updating the isDateSelected to true, then calling notifydatasetchanged.
private var availableDaysList: OrderAvailableDaysResponse = OrderAvailableDaysResponse()
orderAvailableDaysAdapter.setDateClickListener {
for(resItem in availableDaysList){
resItem.isDateSelected = resItem.date_name == it.date_name
}
orderAvailableDaysAdapter.notifyDataSetChanged()
}
Adapter clicklistener
var onDateClickListener: ((OrderAvailableDaysResponseItem) -> Unit)? = null
fun setDateClickListener(listener: (OrderAvailableDaysResponseItem) -> Unit){
onDateClickListener = listener
}
inner class AvailableDaysViewHolder(binding: ItemAvailableDaysBinding) : RecyclerView.ViewHolder(binding.root) {
fun setBindings(itemRes: OrderAvailableDaysResponseItem){
binding.resItem = itemRes
binding.executePendingBindings()
binding.clRoot.setOnClickListener {
onDateClickListener?.let {
it(itemRes)
}
}
}
}
Please refer to the attachment for a better understanding of the situation
As you can see on clicking on an item the items are changing randomly. Please help me. Am I missing something?
Edit 1:
Complete adapter code
class OrderAvailableDaysAdapter(var orderAvailableDaysResponseList: OrderAvailableDaysResponse) : RecyclerView.Adapter<OrderAvailableDaysAdapter.AvailableDaysViewHolder>() {
private lateinit var binding: ItemAvailableDaysBinding
var onDateClickListener: ((OrderAvailableDaysResponseItem) -> Unit)? = null
fun setDateClickListener(listener: (OrderAvailableDaysResponseItem) -> Unit){
onDateClickListener = listener
}
inner class AvailableDaysViewHolder(binding: ItemAvailableDaysBinding) : RecyclerView.ViewHolder(binding.root) {
fun setBindings(itemRes: OrderAvailableDaysResponseItem){
binding.resItem = itemRes
binding.executePendingBindings()
binding.clRoot.setOnClickListener {
onDateClickListener?.let {
it(itemRes)
}
}
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AvailableDaysViewHolder {
binding = ItemAvailableDaysBinding.inflate(LayoutInflater.from(parent.context),parent,false)
return AvailableDaysViewHolder(binding)
}
override fun onBindViewHolder(holder: AvailableDaysViewHolder, position: Int) {
holder.setBindings(orderAvailableDaysResponseList[position])
}
override fun getItemCount(): Int {
return orderAvailableDaysResponseList.size
}}
remove private lateinit var binding: ItemAvailableDaysBinding from adapter, don' keep it "globally", initialisation is made only once, in onCreateViewHolder
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AvailableDaysViewHolder {
ItemAvailableDaysBinding binding = ItemAvailableDaysBinding.inflate(
LayoutInflater.from(parent.context),parent,false)
return AvailableDaysViewHolder(binding)
}
same naming of this "global" object and in AvailableDaysViewHolder inner class may confuse it and setBindings may be called on lastly initialised (global kept) object rather that this passed in constructor
In my app, there is an Activity which has a RecyclerView inside, which loads the list of options needed for that screen.
In the code below, i tried to implement a binder, which is needed because of the recent Android changes.
However, when i open the activity starts, the application crashes, throwing this error, linking the line with binding = ItemSettingsBinding.bind(binding.root):
kotlin.UninitializedPropertyAccessException: lateinit property binding has not been initialized
What am i doing wrong? What's the correct way to implement a binder inside an adapter?
AdapterSettings.kt
class AdapterSettings(
var settingsList: List<DataItemSettings>,
var listener: OnItemClickListener
) : RecyclerView.Adapter<AdapterSettings.SettingsViewHolder>() {
private lateinit var binding: ItemSettingsBinding
inner class SettingsViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener {
init {
itemView.setOnClickListener(this)
}
override fun onClick(p0: View?) {
val position : Int = adapterPosition
if (position != RecyclerView.NO_POSITION) {
listener.OnItemClick(position)
}
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SettingsViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.item_settings, parent, false)
return SettingsViewHolder(view)
}
override fun getItemCount(): Int {
return settingsList.size
}
override fun onBindViewHolder(holder: SettingsViewHolder, position: Int) {
binding = ItemSettingsBinding.bind(binding.root)
holder.itemView.apply {
binding.rvTitle.text = settingsList[position].stringTitle
binding.rvDescription.text = settingsList[position].stringDescription
binding.rvIcon.setImageResource(settingsList[position].itemIcon)
}
}
interface OnItemClickListener {
fun OnItemClick(position: Int)
}
}
I believe you're missing your inflate in onCreateViewHolder:
// Pseudo-Code
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SettingsViewHolder {
val binding = ItemSettingsBinding
.inflate(LayoutInflater.from(parent.context), parent, false)
return SettingsViewHolder(binding)
}
Then you can make use of it.
Create the binding in onCreateViewHolder and pass the binding into the ViewHolder instead of the inflated View. Thus you create a binding for each created view and only need to do the apply stuff in the onBindViewHolder
Example:
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SettingsViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.item_settings, parent, false)
val binding = ItemSettingsBinding.bind(view)
return SettingsViewHolder(binding)
}
override fun onBindViewHolder(holder: SettingsViewHolder, position: Int) {
holder.binding.apply {
rvTitle.text = settingsList[position].stringTitle
rvDescription.text = settingsList[position].stringDescription
rvIcon.setImageResource(settingsList[position].itemIcon)
}
}
Adapt your ViewHolder accordingly
There is indeed another way to ViewBind in an adapter.
First, we need to setup the ViewHolder in a different way:
inner class SettingsViewHolder(private val binding: ItemSettingsBinding):
RecyclerView.ViewHolder(binding.root), View.OnClickListener {
With this, we created a binding value inside the brackets, so we are able to call the items of the actual view or layout trough binding.root
Inside the viewholder, we need to create a function used to bind our items. We can either bind like this:
fun bind(item: Item) {
binding.item = item
binding.executePendingBindings()
}
Or like this:
fun bind(item: DataItemSettings) {
binding.rvTitle.text = settingsList[position].stringTitle
binding.rvDescription.text = settingsList[position].stringDescription
binding.rvIcon.setImageResource(settingsList[position].itemIcon)
}
NOTICE: 'getter for position: Int' is deprecated. Deprecated in Java.
And, final step, we need to write this, inside bindViewHolder:
override fun onBindViewHolder(holder: SettingsViewHolder, position: Int) {
holder.bind(settingsList[position])
}
I have a recyclerView populated by the val microphones: MutableList<Microphone>. There's a button in the row layout to remove that item from the list, which I've managed to get functioning, but the animation is going wrong. It looks like when the recyclerView updates, it removes the last item in the list, then the correct item, and then the whole list below the removed item animates to the correct state.
Here's the relevant bits of the recyclerView adapter:
class RecyclerViewAdapter(
val microphones: MutableList<Microphone>
): RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val cellForRow = LayoutInflater.from(parent.context).inflate(R.layout.favorites_row, parent, false)
return ViewHolder(cellForRow)
}
override fun getItemCount(): Int {
return microphones.size
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val microphone = microphones[position]
holder.bind(microphone)
holder.favoritesButton.setOnClickListener {
microphones.remove(microphone)
notifyItemRemoved(position)
}
}
class ViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
val modelText = view.findViewById<TextView>(R.id.model_textView)
val brandText = view.findViewById<TextView>(R.id.brand_textView)
val favoritesButton = view.findViewById<ImageButton>(R.id.btnFavorite)
fun bind(
microphone: Microphone,
) {
modelText.text = microphone.model
brandText.text = microphone.brand
}
}
}
Here's a screen recording of the issue:
https://imgur.com/a/pJt3KwH
Imagine we have a simple list of items. Each item contains only a short title.
To handle the list we are using RecyclerView with ListAdapter and ViewHolders.
Each item/view is not editable unless we click it.
In this scenario I am using one view model for list and one for item under edit.
Unfortunately all my attempts failed.
I have tried to use two different view holders but the list was flickering, after all inflating view (in this case binding) is heavy.
Another shot I was giving to use the same view holder but with two various bind methods - one binding plain item, second binding with viewmodel instead of data object but it failed as well - suddenly a few rows were editable.
Has anyone solved it ?
class MistakesAdapter(private val editViewModel: MistakeEditViewModel) :
ListAdapter<Mistake, RecyclerView.ViewHolder>(MistakesDiffCallback()) {
companion object{
const val ITEM_PLAIN_VIEW_TYPE = 0
const val ITEM_EDITABLE_VIEW_TYPE = 1
}
private var itemPositionUnderEdit = -1
private val listener = object: MistakeItemListener{
override fun onClick(view: View, position: Int) {
Timber.d("OnClick : edit - $itemPositionUnderEdit, clickPos - $position")
editViewModel.onEditMistake(getItem(position))
itemPositionUnderEdit = position
notifyItemChanged(itemPositionUnderEdit)
}
}
override fun getItemViewType(position: Int) =
when (position) {
itemPositionUnderEdit -> ITEM_EDITABLE_VIEW_TYPE
else -> ITEM_PLAIN_VIEW_TYPE
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
when (viewType) {
ITEM_EDITABLE_VIEW_TYPE -> EditableMistakeViewHolder.from(parent)
else -> MistakeViewHolder.from(parent)
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
when (holder) {
is EditableMistakeViewHolder -> holder.bind(editViewModel, listener)
is MistakeViewHolder -> holder.bind(getItem(position), listener)
else -> throw ClassCastException("Unknown view holder type")
}
}
class MistakeViewHolder private constructor(private val binding: ListItemMistakesBinding) :
RecyclerView.ViewHolder(binding.root) {
companion object {
fun from(viewGroup: ViewGroup): MistakeViewHolder {
val inflater = LayoutInflater.from(viewGroup.context)
val binding = ListItemMistakesBinding.inflate(inflater, viewGroup, false)
return MistakeViewHolder(binding)
}
}
fun bind(item: Mistake, listener: MistakeItemListener) {
binding.apply {
mistake = item
inputType = InputType.TYPE_NULL
this.listener = listener
position = adapterPosition
executePendingBindings()
}
}
}
class EditableMistakeViewHolder private constructor(private val binding: ListItemMistakesBinding)
: RecyclerView.ViewHolder(binding.root) {
companion object{
fun from(viewGroup: ViewGroup): EditableMistakeViewHolder {
val inflater = LayoutInflater.from(viewGroup.context)
val binding = ListItemMistakesBinding.inflate(inflater, viewGroup, false)
return EditableMistakeViewHolder(binding)
}
}
fun bind(viewModel: MistakeEditViewModel, listener: MistakeItemListener){
binding.apply {
this.viewModel = viewModel
inputType = InputType.TYPE_CLASS_TEXT
this.listener = listener
position = adapterPosition
root.setBackgroundColor(Color.GRAY)
}
}
}
}
class MistakeEditViewModel(private val repository: MistakesRepository) : ViewModel() {
#VisibleForTesting
var mistakeUnderEdit: Mistake? = null
//two-way binding
val mistakeName = MutableLiveData<String>()
fun onEditMistake(mistake: Mistake) {
mistakeUnderEdit = mistake
mistakeName.value = mistake.name
}
}
By changing my approach to the problem I solved it.
I make all list items editable but at the same time I am following focus.
To cut the long story short, I invoke item view model methods with help of OnFocusChangeListener and TextWatcher on my editTexts.
I'm new to Android development (and Kotlin).
I'm trying to implement a RecyclerView (which works fine) and when I click on a specific row it opens a new activity (Intent).
However, whenever I've press/click on one of the rows, I'm only able to get the value "-1" returned.
I've tried a number of different approaches (you should see the number of tabs in my browser).
This seems like it should be a fairly straightforward occurrence for something as common as a RecyclerView, but for whatever reason I'm unable to get it working.
Here is my RecyclerView Adapter file:
class PNHLePlayerAdapter (val players : ArrayList<PNHLePlayer>, val context: Context) : RecyclerView.Adapter<ViewHolder>() {
var onItemClick: ((Int)->Unit) = {}
// Gets the number of items in the list
override fun getItemCount(): Int {
return players.size
}
// Inflates the item views
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val itemView = LayoutInflater.from(context).inflate(
R.layout.pnhle_list_item,
parent,
false
)
val viewHolder = ViewHolder(itemView)
itemView.setOnClickListener {
onItemClick(viewHolder.adapterPosition)
}
return ViewHolder(itemView)
}
// Binds each item in the ArrayList to a view
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.tvPlayerName?.text = players[position].Name
holder.tvPlayerRank?.text = position.toString()
holder.tvPNHLe?.text = players[position].PNHLe.toString()
holder.tvTeam?.text = players[position].Team
holder.ivLeague?.setImageResource(leagueImageID)
}
}
class ViewHolder (view: View) : RecyclerView.ViewHolder(view) {
val linLayout = view.hor1LinearLayout
val ivTeam = view.teamImageView
val tvPlayerName = view.playerNameTextView
val tvPlayerRank = view.rankNumTextView
val tvPNHLe = view.pnhleTextView
val tvTeam = view.teamTextView
val ivLeague = view.leagueImageView
}
As you can see, there is a class property "onItemClick" which uses a lambda as the click callback.
I setOnClickListener in the onCreateViewHolder method after the view is inflated.
Next, in my Activity I add the list to my Adapter and set the call back.
However, every time I 'Toast' the position it is displayed as '-1'.
val adapter = PNHLePlayerAdapter(list, this)
adapter.onItemClick = { position ->
Toast.makeText(this, position.toString(),Toast.LENGTH_SHORT).show()
var intent = Intent(this, PlayerCardActivity::class.java)
//startActivity(intent)
}
rv_player_list.adapter = adapter
Perhaps I'm not thinking about this properly, but shouldn't the position represent the row number of the item out of the RecyclerView???
Ideally, I need to use the position so that I can obtain the correct item from the 'list' (ArrayList) so that I can pass information to my next Activity using the Intent
I found the issue.
Change this line in onCreateViewHolder:
return ViewHolder(itemView)
to this one:
return viewHolder
I would reorganize the adapter like this:
class PNHLePlayerAdapter : androidx.recyclerview.widget.RecyclerView.Adapter<Adapter.ViewHolder>() {
interface AdapterListener {
fun onItemSelected(position: Int?)
}
var players: List<Player> = listOf()
set(value) {
field = value
this.notifyDataSetChanged()
}
var listener: AdapterListener? = null
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.item_car_selector, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.bind(position)
}
override fun getItemCount(): Int {
return brands.size
}
inner class ViewHolder(view: View): androidx.recyclerview.widget.RecyclerView.ViewHolder(view) {
private var position: Int? = null
private val baseView: LinearLayout? = view.findViewById(R.id.baseView) as LinearLayout?
...
init {
baseView?.setOnClickListener {
listener?.onManufacturerSelected(position)
}
}
fun bind(position: Int) {
this.position = position
...
}
}
}
And from your activity/fragment set the listener as adapter.listener = this, and implement the onItemSelected(position: Int?)
override fun onItemSelected(position: Int?) {
...
}