Develop Reference

How to show particular number of item at a time in smarteist image slider github

I created the image slider using smarteist image slider github library and it's working fine. I wanted to show 3 items at a time but Item occupies whole space and visible only 1 item. I also tried recyclerview to achieve this thing but can't get same feel as image slider. So guide me how to achieve it.
Expected
To show 3 items at a time before slide.
what I had done
val partner_recyclerView: SliderView = findViewById(R.id.partnership_slider)
var partnerAdapter: PartnerAdapter = PartnerAdapter(partnerList)
partner_recyclerView.autoCycleDirection = SliderView.LAYOUT_DIRECTION_LTR
partner_recyclerView.setSliderAdapter(partnerAdapter)
partner_recyclerView.scrollTimeInSec = 3
partner_recyclerView.isAutoCycle = true
partner_recyclerView.startAutoCycle()
Item_layout
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="150dp"
android:layout_height="80dp"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="5dp"
android:layout_marginTop="8dp"
app:cardElevation="8dp"
android:layout_marginEnd="5dp"
android:layout_marginBottom="8dp"
app:cardCornerRadius="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="#+id/myPartnerLogo"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"
android:layout_gravity="center"
android:contentDescription="#string/app_name"
android:scaleType="fitXY"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</LinearLayout>
</androidx.cardview.widget.CardView></androidx.constraintlayout.widget.ConstraintLayout>
Main_Layout
<com.smarteist.autoimageslider.SliderView
android:id="#+id/partnership_slider"
android:layout_width="wrap_content"
android:layout_height="100dp"
android:layout_centerInParent="true"
app:sliderAnimationDuration="600"
app:sliderAutoCycleDirection="back_and_forth"
app:sliderScrollTimeInSec="1"
android:padding="10dp"
app:layout_constraintBottom_toTopOf="#+id/constraintLayout3"
app:layout_constraintEnd_toEndOf="#+id/constraintLayout3"
app:layout_constraintStart_toStartOf="#+id/constraintLayout3"
app:layout_constraintTop_toTopOf="#+id/constraintLayout3"/>
Adapter_class
class PartnerAdapter (val mList: ArrayList<PartnershipData>) :
SliderViewAdapter<PartnerAdapter.SliderViewHolder>() {
override fun getCount(): Int {
return mList.size
}
override fun onCreateViewHolder(parent: ViewGroup?): PartnerAdapter.SliderViewHolder {
val inflate: View = LayoutInflater.from(parent!!.context).inflate(R.layout.partner_item, null)
return PartnerAdapter.SliderViewHolder(inflate)
}
override fun onBindViewHolder(viewHolder: PartnerAdapter.SliderViewHolder?, position: Int) {
if (viewHolder != null) {
// if view holder is not null we are simply
// loading the image inside our image view using glide library
Glide.with(viewHolder.itemView).load(mList.get(position).pwa_iconpng).fitCenter()
.into(viewHolder.myPartnerLogo)
}
}
class SliderViewHolder (itemView: View?) : SliderViewAdapter.ViewHolder(itemView) {
val myPartnerLogo: ImageView = itemView!!.findViewById(R.id.myPartnerLogo)
}}
For better understanding
Expected
Problem

How to cover up the loading time lag in android Studio?

I have made an app in Android Studio which imports data from a website...when I open the app the card views in which the data is to be imported are empty and get loaded after some time. I wanted to know if there is any way in which I can cover it up so that till the time it is being loaded my splash screen stays there. Here is a video showing the lag:
Card View loading time lag
Edit: Here is the movie Adapter:
class MoviesAdapter(
private var movies: MutableList<Movie>,
private val onMovieClick: (movie: Movie) -> Unit,
) : RecyclerView.Adapter<MoviesAdapter.MovieViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MovieViewHolder {
val view = LayoutInflater
.from(parent.context)
.inflate(R.layout.item_movie, parent, false)
return MovieViewHolder(view)
}
override fun getItemCount(): Int = movies.size
override fun onBindViewHolder(holder: MovieViewHolder, position: Int) {
holder.bind(movies[position])
}
fun appendMovies(movies: List<Movie>) {
this.movies.addAll(movies)
notifyItemRangeInserted(
this.movies.size,
movies.size - 1
)
}
inner class MovieViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
private val poster: ImageView = itemView.findViewById(R.id.item_movie_poster)
fun bind(movie: Movie) {
itemView.setOnClickListener { onMovieClick.invoke(movie) }
Glide.with(itemView)
.load("https://image.tmdb.org/t/p/w342${movie.posterPath}")
.transform(CenterCrop())
.into(poster)
}
}
}
My main_activity_xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/bg_gradient"
android:fitsSystemWindows="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginTop="25dp"
android:layout_marginEnd="16dp"
android:text="#string/discover"
android:textColor="#android:color/white"
android:textSize="45sp"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="#string/popular"
android:textColor="#android:color/white"
android:textSize="22sp"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:text="#string/most_popular_movies" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/popular_movies"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:clipToPadding="false"
android:paddingStart="16dp"
android:paddingEnd="16dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="#string/top_rated"
android:textColor="#android:color/white"
android:textSize="22sp"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:text="#string/highest_rated_movies" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/top_rated_movies"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:clipToPadding="false"
android:paddingStart="16dp"
android:paddingEnd="16dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="#string/upcoming"
android:textColor="#android:color/white"
android:textSize="22sp"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:text="#string/stay_updated" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/upcoming_movies"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="16dp"
android:clipToPadding="false"
android:paddingStart="16dp"
android:paddingEnd="16dp" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="#string/now_playing"
android:textColor="#android:color/white"
android:textSize="22sp"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:text="#string/now_in_Cinemas" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/now_playing_movies"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="10dp"
android:clipToPadding="false"
android:paddingStart="16dp"
android:paddingEnd="16dp" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
Api Key:
interface Api {
#GET("movie/popular")
fun getPopularMovies(
#Query("api_key") apiKey: String =
"eff7d87eb14cdf1fb273414692d3e3a8",
#Query("page") page: Int,
): Call<GetMoviesResponse>
}
Api Loader:
api.getPopularMovies(page = page)
.enqueue(object : Callback<GetMoviesResponse> {
override fun onResponse(
call: Call<GetMoviesResponse>,
response: Response<GetMoviesResponse>,
) {
if (response.isSuccessful) {
val responseBody = response.body()
if (responseBody != null) {
onSuccess.invoke(responseBody.movies)
} else {
onError.invoke()
}
} else {
onError.invoke()
}
}
override fun onFailure(call: Call<GetMoviesResponse>, t:
Throwable) {
onError.invoke()
}
})
Is there anything else that I should specify?

without code it's hard to answer the question, but you could always use a ViewSwitcher that displays a "Loading" state before the data for the cardviews are ready, but holds the space, so the UI won't jump, and then have the Card view displayed once the data is loaded.
Could be something like:
sealed class CardData {
object Loading: CardData()
class Info(val items: List<CardInfo>): CardData()
}
fun loadData() {
viewModel.cardData.observe { cardData ->
when(cardData) {
is Loading -> {
binding.switcher.displayedChild = 0
}
is Info -> {
binding.switcher.displayedChild = 1
binding.listOfCards.items = cardData.items
}
}
}
for your specific case:
// display the loading view before making the call
binding.switcher.displayedChild = 0
api.getPopularMovies(page = page)
.enqueue(object : Callback<GetMoviesResponse> {
override fun onResponse(
call: Call<GetMoviesResponse>,
response: Response<GetMoviesResponse>,
) {
if (response.isSuccessful) {
val responseBody = response.body()
if (responseBody != null) {
onSuccess.invoke(responseBody.movies)
} else {
onError.invoke()
}
} else {
onError.invoke()
}
}
override fun onFailure(call: Call<GetMoviesResponse>, t:
Throwable) {
onError.invoke()
}
})
// in your onSuccess()
private void onSuccess(List<Movies> movies) {
binding.switcher.displayedChild = 1
listAdapter.items = movies
listAdapter.notifyDatasetChanged()
}
// in your onError()
private void onError() {
binding.switcher.displayedChild = 2 // you can add a third child for errors
}
then the XML would be something like (missing attributes):
<ViewSwitcher
android:id="#+id/switcher">
<!-- child 0 - loading state -->
<ProgressBar
android:id="#+id/loader"
/>
<!-- child 1 - movies state -->
<RecyclerView
android:id="#+id/movies"
/>
<!-- child 2 - error state -->
<TextView
android:id="#id/error_text"
/>
</ViewSwitcher>

If you want to wait in the splash screen, you will need to make that request in the splash screen.
When you have a successful response, you then navigate and pass the data through args/intent extras, assuming this is a different fragment/activity.
Then, when you are setting creating the list adapter you just need to pass this list through the constructor and set wire everything up, like you probably already have.
Hope it helps, but let me know if this wasn't clear enough!

You can create a Splash screen view exactly like your splash screen in your main activity and show it first while loading all the data from the network in the background, once the data arrives, hide this splash screen view and show app's main screen.
You can instead use shimmer effect to show data loading in background.

Kotlin Android onClickListener in getView only works on edge

I'm new to Kotlin and Android development in general. I have created a custom adapter that extends BaseAdapter and it works as I want it to, but as soon as I was to add a click listener to the view that gets returned in the getView, it doesn't seem to work as expected.
I have looked everywhere for an answer. I have seen people talking about clickable, duplicateParentState, focusable,... But nothing seems to work
The click listener does react if I click on the left/right border of my layout RelativeLayout, but I want the entire RelativeLayout to react when I click.
Am I missing something in my XML? Or is there some kind of "hack" that works. I'm a little confused as to why my click listener is not working as expected
My TokenAdapter (extends BaseAdapter)
class TokenAdapter(private val ctx: Context) : BaseAdapter() {
private val tokenPersistence: TokenPersistence = TokenPersistence(ctx)
private val clipboardManager: ClipboardManager =
ctx.getSystemService(Context.CLIPBOARD_SERVICE) as ClipboardManager
var seconds: Int
var percentage: Int = 100
var shouldGenerateToken: Boolean = true
init {
seconds = getSecondsUntilRefresh()
}
fun getSecondsUntilRefresh() : Int{
val secondsElapsedInMinute = LocalDateTime.now().second
return if(secondsElapsedInMinute < 30) 30 - secondsElapsedInMinute else 60 - secondsElapsedInMinute
}
override fun getCount(): Int {
return tokenPersistence.length()
}
override fun getItem(position: Int): Token? {
return tokenPersistence.get(position)
}
override fun getItemId(position: Int): Long {
return position.toLong()
}
override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
val v: View = if (convertView == null) {
val inflater: LayoutInflater =
ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
inflater.inflate(R.layout.list_item, parent, false)
} else {
convertView
}
val t: Token = getItem(position)!!
val title: TextView = v.findViewById(R.id.list_item_title)
val code: TextView = v.findViewById(R.id.list_item_subtitle)
title.text = t.getLabel()
if (shouldGenerateToken) {
var generatedCode : String = t.generateCode()
generatedCode = generatedCode.substring(0, 3) + " " + generatedCode.substring(3, generatedCode.length)
code.text = generatedCode
shouldGenerateToken = false
}
val countdown: ProgressBar = v.findViewById(R.id.progress_circular)
val countdownText: TextView = v.findViewById(R.id.progress_circular_text)
countdownText.text = seconds.toString()
countdown.progress = percentage
v.setOnClickListener {
val copyText = code.text.split(' ').joinToString("")
println("===================")
println("Copied: $copyText")
val clip: ClipData = ClipData.newPlainText("2FA Code", copyText)
clipboardManager.setPrimaryClip(clip)
Toast.makeText(ctx, "Copied: $copyText to clipboard", Toast.LENGTH_LONG).show()
}
return v
}
}
The list_item XML layout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/list_item_container"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/list_item_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="#000000"
android:textSize="16sp"
android:textStyle="bold"
android:paddingHorizontal="8dp"
android:paddingTop="16dp"
android:paddingBottom="0dp"
android:clickable="false"
/>
<TextView
android:id="#+id/list_item_subtitle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_below="#id/list_item_title"
android:layout_alignParentStart="true"
android:layout_alignParentLeft="true"
android:layout_toStartOf="#id/progress_circular_container"
android:layout_toLeftOf="#id/progress_circular_container"
android:paddingHorizontal="8dp"
android:paddingTop="0dp"
android:text="123456"
android:textColor="#color/primary"
android:textSize="32sp"
android:textStyle="bold"
android:clickable="false"/>
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/progress_circular_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_below="#id/list_item_title"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:clickable="false">
<ProgressBar
android:id="#+id/progress_circular"
android:layout_width="48sp"
android:layout_height="48sp"
android:indeterminateOnly="false"
android:progressDrawable="#drawable/pb_circular_determinative"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:progress="100"/>
<TextView
android:id="#+id/progress_circular_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#android:color/black"
app:layout_constraintBottom_toBottomOf="#+id/progress_circular"
app:layout_constraintEnd_toEndOf="#+id/progress_circular"
app:layout_constraintStart_toStartOf="#+id/progress_circular"
app:layout_constraintTop_toTopOf="#+id/progress_circular"
tools:text="30" />
</androidx.constraintlayout.widget.ConstraintLayout>
</RelativeLayout>

So I managed to fix my problem.
I did 2 "major" things after which my problem was resolved:
I rewrote my list_item.xml making use of LinearLayout instead of RelativeLayout (although I doubt this did anything)
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="#+id/list_item_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#000000"
android:textSize="16sp"
android:textStyle="bold"
android:paddingHorizontal="8dp"
android:paddingTop="16dp"
android:paddingBottom="0dp"
/>
<TextView
android:id="#+id/list_item_subtitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingHorizontal="8dp"
android:paddingTop="0dp"
android:textColor="#color/primary"
android:textSize="32sp"
android:textStyle="bold"
/>
</LinearLayout>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center">
<ProgressBar
android:id="#+id/progress_circular"
android:layout_width="48sp"
android:layout_height="48sp"
android:indeterminateOnly="false"
android:progressDrawable="#drawable/pb_circular_determinative"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:progress="100"/>
<TextView
android:id="#+id/progress_circular_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#android:color/black"
app:layout_constraintBottom_toBottomOf="#+id/progress_circular"
app:layout_constraintEnd_toEndOf="#+id/progress_circular"
app:layout_constraintStart_toStartOf="#+id/progress_circular"
app:layout_constraintTop_toTopOf="#+id/progress_circular"
tools:text="30" />
</androidx.constraintlayout.widget.ConstraintLayout>
I moved my ClickListener from my Adapter getView() to my MainActivity with an setOnItemClickListener on my ListView
val listview = findViewById<ListView>(R.id.tokenList)
listview.setOnItemClickListener { parent: AdapterView<*>, view: View, position: Int, id ->
val token = tokenAdapter.getItem(position)
if(token != null) {
val code = token.generateCode()
val clip: ClipData = ClipData.newPlainText("2FA Code", code)
clipboardManager.setPrimaryClip(clip)
Toast.makeText(this, "Copied: $code", Toast.LENGTH_LONG).show()
}
}
Using this method on my Listview I also didn't have to use clickable, or any of those kinds of properties on my XML layouts. If someone knows what exactly made it work, please tell me. Personally I think it is the Listener being an 'OnItemClick' and it being moved to the MainActivity, although don't take my word for it as it could just be something else random that I did.

After refreshing data, the RecyclerView seems to move down on the screen

Using LiveData<PagedList> to display a recycler view that hits a Room database. When I do a search on screen, the number of items returned is less, however, there seems to be a lot of extra white space between the recycler view and the other buttons. The recycler view itself shrinks, and then moves down on the screen.
Here is the way it looks before the data is refreshed (before I do a search):
Here is after:
Here is my adapter for the recyclerView:
class WorkPackagesRecyclerAdapter(
private val onWorkPackageClickListener: OnClickWorkPackage
) : PagedListAdapter<Workpackage,
WorkPackagesRecyclerAdapter.WorkPackagesViewHolder>(
REPO_COMPARATOR
) {
interface OnClickWorkPackage {
fun clickWorkPackage(workPackageId: String)
}
override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): WorkPackagesViewHolder {
val inflater = LayoutInflater.from(viewGroup.context)
val binding = inflate<ItemWorkPackageBinding>(
inflater,
R.layout.item_work_package,
viewGroup,
false
)
return WorkPackagesViewHolder(binding, viewGroup.context)
}
override fun onBindViewHolder(holder: WorkPackagesViewHolder, position: Int)
{
getItem(position)?.let {
holder.bind(it)
}
}
inner class WorkPackagesViewHolder(
internal var binding: ItemWorkPackageBinding,
internal val context: Context
) : RecyclerView.ViewHolder(binding.root), KoinComponent {
fun bind(data: Workpackage) {
val itemWorkPackagesViewModel: ItemWorkPackagesViewModel by inject{ parametersOf(data)}
this.binding.listItem.setOnClickListener {
onWorkPackageClickListener.clickWorkPackage(data.id)
}
this.binding.viewmodel = itemWorkPackagesViewModel
this.binding.executePendingBindings()
}
}
companion object {
private val REPO_COMPARATOR =
object : DiffUtil.ItemCallback<Workpackage>() {
override fun areItemsTheSame(
oldItem: Workpackage,
newItem: Workpackage
): Boolean =
oldItem.id == newItem.id
override fun areContentsTheSame(
oldItem: Workpackage,
newItem: Workpackage
): Boolean =
oldItem == newItem
}
}
Here is how I set up the PagedList:
val searchQuery: MutableLiveData<SearchAndSort> = MutableLiveData(
SearchAndSort("",
WorkpackagesRepository.Companion.SortedBy.WorkPackageNumber,
AscendDescend.ASC))
var workPackagesList = Transformations.switchMap(searchQuery) { searchQuery ->
val factory = workPackageStorageDao.searchWorkpackages(
searchQuery.searchText,
searchQuery.sortBy.type + " " + searchQuery.ascendDescend.text
)
val pagedListBuilder = LivePagedListBuilder<Int, Workpackage>(factory, pagingLimit)
pagedListBuilder.build()
}
Here is where I am observing the adapter:
workPackagesViewModel.workPackagesList.observe(this, Observer { wpList ->
wpList ?: return#Observer
adapter = WorkPackagesRecyclerAdapter(this)
adapter.submitList(wpList)
binding.workPackagesRecyclerView.adapter = adapter
adapter.notifyDataSetChanged()
})
Here is the layout of the recycler view
<?xml version="1.0" encoding="utf-8"?>
<layout
xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="viewModel"
type="com.bechtel.pf.ui.workpackages.WorkPackagesViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="727dp"
tools:layout_editor_absoluteY="1dp">
<EditText
android:id="#+id/search_bar_edit_text"
android:layout_width="match_parent"
android:layout_height="55dp"
android:layout_marginTop="#dimen/work_package_margin"
android:hint="#string/work_packages_search_hint"
app:layout_constraintBottom_toBottomOf="#id/guideline"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<ImageButton
android:id="#+id/search_bar_magnifying_glass"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginTop="#dimen/work_package_margin"
android:background="#drawable/icons_search"
app:layout_constraintBottom_toBottomOf="#id/guideline"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline"
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintGuide_begin="#dimen/work_package_search_guideline_start"
/>
<com.google.android.material.button.MaterialButton
android:id="#+id/btnSortBy"
android:layout_width="0dp"
android:layout_height="45dp"
android:layout_marginTop="5dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:backgroundTint="#color/colorPrimary"
app:layout_constraintEnd_toStartOf="#+id/btnAscendDescend"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/guideline"
app:layout_constraintHorizontal_chainStyle="spread"
android:text="#string/work_packages_sort"
/>
<com.google.android.material.button.MaterialButton
android:id="#+id/btnAscendDescend"
android:layout_width="0dp"
android:layout_height="45dp"
android:layout_marginTop="5dp"
android:layout_marginEnd="10dp"
android:backgroundTint="#color/colorPrimary"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintEnd_toStartOf="#+id/btnFilterBy"
app:layout_constraintStart_toEndOf="#+id/btnSortBy"
app:layout_constraintTop_toBottomOf="#+id/guideline"
app:layout_constraintHorizontal_chainStyle="spread"
android:text="#string/work_packages_ascend"
android:onClick="#{() -> viewModel.ascendingDescending()}"
/>
<com.google.android.material.button.MaterialButton
android:id="#+id/btnFilterBy"
android:layout_width="0dp"
android:layout_height="45dp"
android:layout_marginTop="5dp"
android:layout_marginEnd="10dp"
android:backgroundTint="#color/colorPrimary"
app:layout_constraintHorizontal_weight="1"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/btnAscendDescend"
app:layout_constraintTop_toBottomOf="#+id/guideline"
android:text="#string/work_packages_filter"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/workPackagesRecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"
android:layout_marginTop="75dp"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnFilterBy">
</androidx.recyclerview.widget.RecyclerView>
</androidx.constraintlayout.widget.ConstraintLayout>
Anyone ever seen anything like this before? I've also made sure that I am using layout_height = wrap_content in my recyclerview layout and item.xml files.
Screenshot inspector:

OK, it looks like I had set the recyclerview layout_constraintBottom_toBottomOf was set to 'parent' and since the total height of the recyclerview shrunk when the number of items shrunk, it was moving the view to the bottom of the screen. I also could get rid of the top margin attribute and the recycler view stayed below the buttons. So now I have:
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/workPackagesRecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btnFilterBy"/>
And it all looks good!

Recyclerview missing item when element's width and height is enlarged

I've been scratching my head about this problem. I have a recyclerview inside a recyclerview that shows a grid layout where you can scroll both vertically and horizontally.
I decided to enlarge the width and height of each item. Previously, width and height were: 80 x 100
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/book_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/inner_dropshadow"
android:layout_width="80dp"
android:layout_height="100dp"
android:scaleType="fitXY"
app:layout_constraintBottom_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/bookdropshadow" />
</android.support.constraint.ConstraintLayout>
And then I enlarged it to 150x 180. And then Level 4-6 row completely disappeared no matter how much I scroll up. I only expected the recyclerview to display larger images. Why does this happen?
[EDIT] I ran a debug and it seems only 3 positions are bound in the outer adapter when the app is run on a phone but there are 4 positions when run on a tablet.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/book_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/inner_dropshadow"
android:layout_width="150dp"
android:layout_height="180dp"
android:scaleType="fitXY"
app:layout_constraintBottom_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/bookdropshadow" />
</android.support.constraint.ConstraintLayout>
Please note that this also happens when I run the app on a device. In a tablet, it shows all the Levels, while on a phone, it only shows Levels 1-3.
Outer recyclerview layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/mainlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/color_white">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.SwipeRefreshLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:id="#+id/swiperefresh"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#+id/toolbar">
<ScrollView
android:id="#+id/scrollView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="always">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="#layout/browsebooksheader_layout"
android:id="#+id/bb_header"
app:layout_constraintBottom_toTopOf="#+id/guidelinetop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="parent"/>
<android.support.constraint.Guideline
android:id="#+id/guidelinetop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.30"/>
<Button
android:id="#+id/btn_search"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:background="#drawable/search_btn_border"
android:padding="8dp"
android:text="Search"
android:textSize="#dimen/browse_search_textsize"
android:textColor="#android:color/darker_gray"
app:layout_constraintBottom_toTopOf="#+id/recyclerview_main"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/bb_header" />
<ProgressBar
android:id="#+id/main_progressbar"
style="?android:attr/progressBarStyleSmall"
android:layout_marginTop="16dp"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_gravity="center"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:indeterminateTint="#color/color_grey"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btn_search"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerview_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:nestedScrollingEnabled="false"
android:background="#color/color_white"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/btn_search"
app:layout_constraintBottom_toBottomOf="parent"/>
</android.support.constraint.ConstraintLayout>
</ScrollView>
</android.support.v4.widget.SwipeRefreshLayout>
<android.support.constraint.ConstraintLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:id="#+id/toolbar"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/swiperefresh"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent">
<include layout="#layout/toolbar_layout_wo_learn"/>
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
Inner recyclerview layout
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/book_category"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Category Title"
android:textColor="#color/defaultdark_color"
android:textSize="#dimen/browse_category_textsize"
android:fontFamily="#font/vagroundedstd_bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:layout_width="#dimen/browse_seeall_imagesize"
android:layout_height="#dimen/browse_seeall_imagesize"
android:layout_marginBottom="2dp"
android:layout_marginTop="2dp"
android:layout_marginEnd="8dp"
android:id="#+id/see_all_btn"
android:src="#drawable/seeall"
app:layout_constraintBottom_toTopOf="#+id/inner_recyclerview"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.v7.widget.RecyclerView
android:id="#+id/inner_recyclerview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:nestedScrollingEnabled="false"
android:background="#color/color_white"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/book_category"/>
<TextView
android:id="#+id/h_line"
android:layout_width="match_parent"
android:layout_height="0.8dp"
android:background="#color/color_grey"
android:gravity="center"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:alpha="0.5"
app:layout_constraintTop_toBottomOf="#id/inner_recyclerview"/>
</android.support.constraint.ConstraintLayout>
Outer Adapter
class BrowseBooksAdapter : RecyclerView.Adapter<BrowseBooksAdapter.SimpleViewHolder>() {
private var sortedList : SortedMap<String, List<ResourcesList>> = emptyMap<String, List<ResourcesList>>().toSortedMap()
fun setData(sortedList : SortedMap<String, List<ResourcesList>>) {
if (this.sortedList != sortedList) {
this.sortedList = sortedList
notifyDataSetChanged()
}
}
override fun getItemCount(): Int {
return sortedList.count()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SimpleViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.browsebooks_layout, parent, false)
return SimpleViewHolder(view)
}
override fun onBindViewHolder(holder: SimpleViewHolder, position: Int) {
val dataList = ArrayList(sortedList.values)[position]
holder.category_text.text = ArrayList(sortedList.keys)[position]
holder.booksByCategory = dataList
holder.horizontalAdapter.setData(dataList)
}
class SimpleViewHolder(v: View, var booksByCategory : List<ResourcesList>? = null) : RecyclerView.ViewHolder(v) {
var recyclerView : RecyclerView = v.findViewById(R.id.inner_recyclerview)
var category_text : TextView = v.findViewById(R.id.book_category)
var fragmentCallback: FragmentCallback? = null
val horizontalAdapter: BooksByCategoryAdapter
init {
recyclerView.layoutManager = object : LinearLayoutManager(v.context, LinearLayoutManager.HORIZONTAL, false) {
override fun canScrollHorizontally(): Boolean {
return true
}
override fun canScrollVertically(): Boolean {
return false
}
}
horizontalAdapter = BooksByCategoryAdapter()
recyclerView.adapter = horizontalAdapter
fragmentCallback = v.context as FragmentCallback
var mLastClickTime : Long = 0
v.see_all_btn.setOnClickListener {
val category = v.book_category.text.toString()
// double-clicking prevention, using threshold of 1000 ms
if (!(SystemClock.elapsedRealtime() - mLastClickTime < 1000)){
mLastClickTime = SystemClock.elapsedRealtime()
if(fragmentCallback != null){
fragmentCallback!!.callBackSeeAllFragment(booksByCategory!!, category)
}
}
}
}
}
}
Inner Adapter
class BooksByCategoryAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private var booksByCategory: List<ResourcesList> = emptyList()
fun setData(data: List<ResourcesList>) {
if (this.booksByCategory != data) {
this.booksByCategory = data
notifyDataSetChanged()
}
}
override fun getItemCount(): Int {
return booksByCategory.size
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
val layoutInflater = LayoutInflater.from(parent.context)
val cellForRow = layoutInflater.inflate(R.layout.bookcontainer_layout, parent, false)
return CustomVH(cellForRow)
}
override fun onBindViewHolder(rawHolder: RecyclerView.ViewHolder, position: Int) {
val holder = rawHolder as CustomVH
val booksProcessModel = BooksProcessModel()
booksProcessModel.setItem(booksByCategory[position])
holder.booksByCategory = booksByCategory[position]
Picasso.get().load(booksByCategory[position].coverURI).into(holder.inner_bookcover)
}
private inner class CustomVH(v: View, var booksByCategory : ResourcesList? = null): RecyclerView.ViewHolder(v) {
var inner_bookcover : ImageView = v.findViewById(R.id.inner_bookcover)
var fragmentCallback: FragmentCallback? = null
var ctx : Context = v.context
var mLastClickTime : Long = 0
init {
fragmentCallback = ctx as FragmentCallback
v.setOnClickListener {
// double-clicking prevention, using threshold of 1000 ms
if (!(SystemClock.elapsedRealtime() - mLastClickTime < 1000)){
mLastClickTime = SystemClock.elapsedRealtime()
if(fragmentCallback != null){
fragmentCallback!!.callBackDownloadBookFragment(booksByCategory!!)
}
}
}
}
}
class BooksProcessModel {
private var processBooks : ResourcesList? = null
fun setItem(books: ResourcesList) {
this.processBooks = books
}
fun setVisibility(ctx: Context) : Int {
val sp = PreferenceManager.getDefaultSharedPreferences(ctx)
val page = sp.getString(processBooks!!.id.toString(), "")
if (page != "") {
return View.VISIBLE
}
return View.INVISIBLE
}
}
}

You need to change the layout_height of the outer recycler view to wrap_content.

Nevermind, figured it out. I should be using a NestedScrollView instead of a ScrollView. The missing items were still there. It's just that I couldn't scroll the nested recyclerview.

In my case it was because I had the RecyclerView directly and even though it scrolled (horizontally), the same thing happened to me if for example the keyboard appeared.
Solution: Put the RecyclerView inside a NestedScrollView and delegate the scroll to it, like this:
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:listitem="#layout/item"/>
</androidx.core.widget.NestedScrollView>