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Data not displayed on recycler view

I have a recycler view issue where the data is not being displayed. onCreateViewHolder and onBindViewHolder are not being called. When I call notifyDataSetChanged(), notifyChanged() is called but mObservers is empty, so it won't update my list.
public void notifyChanged() {
for (int i = mObservers.size() - 1; i >= 0; i--) {
mObservers.get(i).onChanged();
}
}
here's my adapter code:
class ReleasesAdapter : RecyclerView.Adapter<ReleasesAdapter.ReleasesViewHolder>() {
private val data = mutableListOf<Album>(Album())
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ReleasesViewHolder {
return ReleasesViewHolder(
LayoutInflater.from(parent.context)
.inflate(R.layout.song_item, parent, false)
)
}
override fun onBindViewHolder(holder: ReleasesViewHolder, position: Int) {
holder.bindView(data[position])
}
override fun getItemCount(): Int {
return data.size
}
fun setItems(items: List<Album>) {
data.addAll(items)
notifyDataSetChanged()
}
inner class ReleasesViewHolder(
override val containerView: View
) : RecyclerView.ViewHolder(containerView), LayoutContainer {
fun bindView(item: Album) {
containerView.nameTv.text = item.name
}
}
}
And here's my activity code:
#AndroidEntryPoint
class MainActivity : AppCompatActivity(), Contract.View {
#Inject
lateinit var presenter: Contract.Presenter
private val releasesAdapter = ReleasesAdapter()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
resultsRv.run {
adapter = releasesAdapter
layoutManager = LinearLayoutManager(this#MainActivity)
}
presenter.loadNewReleases()
}
override fun showReleases(data: List<Album>) {
releasesAdapter.setItems(data)
}
override fun showErrorMessage(message: String) {
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat 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:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".presentation.MainActivity">
<com.google.android.material.appbar.MaterialToolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/resultsRv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:listitem="#layout/song_item" />
</androidx.appcompat.widget.LinearLayoutCompat>
song_item.xml
<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.textview.MaterialTextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/nameTv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/song_item_margin"
android:textColor="#color/black" />
Please send help :(
Edit: Added Xml code

I believe you are using the scope functions wrong especially run in this case. Use run() function if you need to compute some value or want to limit the scope of multiple local variables.
So while your other code seems okay, I believe your Adapter and LayoutManager is not being assigned. I would suggest you replace the run with apply and try again.
resultsRv.apply {
adapter = releasesAdapter
layoutManager = LinearLayoutManager(this#MainActivity)
}

All child recyclerView's items changed when one child recyclerview's item is changed while click the item

I am working with nested recyclerView. According to business logic, first I have to call an API that fetched the list of item that is shown in the Parent recycler view. After that, if a user clicks any of the items of the parent recycler view, another API is called which fetches a list of sub-items, and I have to show the item list in the inner recycler view of that clicked-positioned parent recycler view.
I successfully implemented showing items in the parent recycler view and sub-items in the clicked-position nested recycler view.
But the problem I am facing is when I clicked any specific item of the parent recycler view, all the other nested recycler view's item get changed with the newly populated sub-items value.
How can I solve this issue?. Here is the sample code
main_item.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat 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"
android:orientation="vertical">
<com.google.android.material.card.MaterialCardView
style="#style/CardViewStyle"
android:id="#+id/chapter_layout"
android:layout_width="match_parent">
<com.google.android.material.textview.MaterialTextView
android:id="#+id/chapter_name_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<com.google.android.material.textview.MaterialTextView
android:id="#+id/header_text_view"
android:layout_width="0dp"
android:layout_height="wrap_content"/>
</com.google.android.material.card.MaterialCardView>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/chapter_topic_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
tools:itemCount="3"
tools:listitem="#layout/item_main" />
</androidx.appcompat.widget.LinearLayoutCompat>
MainItemViewHolder.kt
class MainItemViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
fun bind(item: SpecificChapter, onClick: (SpecificChapter, Int) -> Unit) {
with(view) {
chapter_name_text_view.text = "Chapter "+ item.no
header_text_view.text = item.name
chapter_layout.setOnClickListener { onClick(item, bindingAdapterPosition) }
}
}
}
MainItemAdapter.kt
class MainItemAdapter(
val onClick: (SpecificChapter, Int) -> Unit
) : ListAdapter<SpecificChapter, MainItemViewHolder>(DIFF_CALLBACK) {
companion object {
private val DIFF_CALLBACK = object : DiffUtil.ItemCallback<SpecificChapter>() {
override fun areItemsTheSame(old: SpecificChapter, aNew: SpecificChapter) = (old.id == aNew.id)
override fun areContentsTheSame(old: SpecificChapter, aNew: SpecificChapter) = (old == aNew)
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MainItemViewHolder {
return MainItemViewHolder(parent.inflate(R.layout.main_item))
}
override fun onBindViewHolder(holder: MainItemViewHolder, position: Int) {
holder.bind(getItem(position)!!, onClick)
}
}
sub_item.xml
<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView
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">
<com.google.android.material.textview.MaterialTextView
android:id="#+id/chapter_topic_text_view"
android:layout_width="0dp"
android:layout_height="wrap_content" />
</com.google.android.material.card.MaterialCardView>
SubItemViewHolder.kt
class SubItemViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
fun bind(item: SpecificTopic, onClick: (SpecificTopic) -> Unit) {
with(view) {
chapter_topic_text_view.text = item.name
chapter_topic_layout.setOnClickListener { onClick(item) }
}
}
}
SubItemAdapter.kt
class SubItemAdapter(
val onClick: (SpecificTopic) -> Unit
) : ListAdapter<SpecificTopic, SubItemViewHolder>(DIFF_CALLBACK) {
companion object {
private val DIFF_CALLBACK = object : DiffUtil.ItemCallback<SpecificTopic>() {
override fun areItemsTheSame(old: SpecificTopic, aNew: SpecificTopic) = (old.id == aNew.id)
override fun areContentsTheSame(old: SpecificTopic, aNew: SpecificTopic) = (old == aNew)
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SubItemViewHolder {
return SubItemViewHolder(parent.inflate(R.layout.sub_item))
}
override fun onBindViewHolder(holder: SpecificTopicViewHolder, position: Int) {
holder.bind(getItem(position)!!, onClick)
}
}
activity_chapter.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.LinearLayoutCompat
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/chapter_recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
tools:listitem="#layout/main_item"/>
</androidx.appcompat.widget.LinearLayoutCompat>
ChapterActivity.kt
class ChapterActivity : BaseActivity<ChapterViewModel>() {
var chapterPosition = 0
private val mainItemAdapter: MainItemAdapter by lazy {
MainItemAdapter { specificChapter, position ->
// sub item Api call when clicked specific item. response is viewmodel.allTopics
chapterPosition = position
specificChapter.id?.let { viewModel.getChapterWiseTopics(it) }
}
}
private val subItemAdapter: SubItemAdapter by lazy {
SubItemAdapter {
}
}
override fun onResume() {
super.onResume()
// Main item Api call. response is viewmodel.allChapters
viewModel.getChapters("subject_code")
}
override fun observeLiveData() {
// showing Main item in parent recyclerView
observe(viewModel.allChapters) {
val chapterList = ArrayList<SpecificChapter>()
chapterList.add(SpecificChapter(...))
chapter_recycler_view.adapter = mainItemAdapter
mainItemAdapter.submitList(chapterList)
chapter_recycler_view.setItemViewCacheSize(chapterList.size)
}
// showing sub item in nested recyclerView
observe(viewModel.allTopics) {
val topicList = ArrayList<SpecificTopic>()
topicList.add(SpecificTopic(...))
with((chapter_recycler_view.findViewHolderForAdapterPosition(chapterPosition) as MainItemViewHolder).itemView) {
this.chapter_topic_recycler_view.adapter = subItemAdapter
subItemAdapter.submitList(topicList)
}
}
}
}

On Click implementation not working in Kotlin

I am implementing on Click listener in Kotlin and it is not working. When i click on button nothing happens. Below is the code:
class MainActivity : AppCompatActivity(), View.OnClickListener{
var area: MaterialButton? = null; var length: MaterialButton? = null
var time: MaterialButton? = null;
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
area = findViewById(R.id.button_area)
length = findViewById(R.id.button_length)
time = findViewById(R.id.button_time)
setClickListeners()
}
private fun setClickListeners() {
area?.setOnClickListener(this)
length?.setOnClickListener(this)
time?.setOnClickListener(this)
}
fun toggleDrawer(view: View) {
showToast("Drawer")
}
fun openSettings(view: View) {}
override fun onClick(v: View) {
when (v.id) {
R.id.button_area, R.id.button_length,
R.id.button_time -> showToast("Click")
else ->{
showToast("Drawer")
}
}
}
private fun showToast(str: String){
Toast.makeText(this,str,Toast.LENGTH_LONG).show()
}
}
XML onClick attribute is not working.
<include
layout="#layout/toolbar_content"/>
I have included layout with include property, in main activity(xml). Included view onClick methods are:
fun toggleDrawer(view: View) {
showToast("Drawer")
}
fun openSettings(view: View) {}
They are not working. Infact i am getting error. Could not find a method toggleDrawer(View) in the activity class android.view.ContextThemeWrapper for onClick handler on view class com.google.android.material.button.MaterialButton with id 'drawer_icon'. I have declared these methods in MaterialButton tag. The layout of this button is toolbar_content.
How to resolve all these issues.

If You want to set onClick to specific View in the included layout use this in onCreate:
// Apply click listener to one view in the included layout
val includedLayoutButton: View = findViewById<View>(R.id.includedLayout).findViewById(R.id.butInIncludedLayout)
includedLayoutButton.setOnClickListener {
Log.d("in", "on click")
}
main.xml
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="#+id/includedLayout"
layout="#layout/layout_test" />
</androidx.constraintlayout.widget.ConstraintLayout>
layout_test.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/root"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<Button
android:id="#+id/butInIncludedLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
</FrameLayout>

setting focus on parent of listview layout

I stocked in a problem. I have a listView and this listView is just for showing data row by row and items are all disabled using override function isEnabled to false.
so this is my code:
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/baseLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?selectableItemBackground"
android:clickable="true"
android:focusable="true"
android:paddingTop="10dp"
android:paddingBottom="10dp">
<ListView
android:id="#+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clickable="false"
android:divider="#null"
android:dividerHeight="0dp"
android:focusable="false"
android:focusableInTouchMode="false"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
I need to set click listener on baseLayout but every thing I've done not made the focus on baseLayout and listview calls absListView touch listener. any idea?
...

You have to set listener on list cell, such as.
It is example for recyler view, but it is same case on listview.
class SearchListAdapter(private val context: Context) :
RecyclerView.Adapter() {
private var products: List<Repo> = arrayListOf()
var listener: AdapterListener? = null
override fun onCreateViewHolder(parent: ViewGroup, i: Int): ViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.item_repo, parent, false)
return ViewHolder(view)
}
override fun getItemCount(): Int {
return products.size
}
override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
viewHolder.bind(position, products[position])
}
fun setList(contacts: List<Repo>) {
this.products = contacts
notifyDataSetChanged()
}
inner class ViewHolder(itemView: View) : BindingViewHolder<ItemRepoBinding>(itemView) {
fun bind(pos: Int, contact: Repo) {
if (binding == null) {
return
}
binding.tvTitle.text = contact.name
binding.setVariable(
BR.tintlist,
context.resources.getColorStateList(R.color.xml_color_btn_title)
)
binding.root.setOnClickListener(View.OnClickListener {
if (listener != null) {
listener?.onClick(pos, contact)
}
})
}
}
interface AdapterListener {
fun onClick(position: Int, info: Repo)
}
}

How can I get access to outside views from an Adapter

I have a recyclerview in my app showing a list of content. If a user is subscribed, they can proceed to read the full content and if not the recyclerview is hidden and a subscribe layout is shown.
Layout file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/light_grey"
android:orientation="vertical"
android:weightSum="10"
tools:layout_editor_absoluteY="25dp">
<!--RECYCLER VIEW-->
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginEnd="10dp"
android:layout_marginStart="10dp"
android:layout_marginTop="5dp"
android:layout_weight="8.3"
android:padding="2dp"
android:visibility="gone" />
<!--SUBSCRIBE TO VIEW CONTENT LAYOUT-->
<RelativeLayout
android:id="#+id/rlSubscribeToView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:gravity="center"
android:visibility="gone"
android:layout_margin="10dp"
android:elevation="48dp"
android:layout_gravity="center"
android:layout_weight="8.3">
<TextView
android:id="#+id/tvSubscribe"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_centerInParent="true"
android:textColor="#color/maroon"
android:text="#string/subscribe_to_view"/>
<Button
android:id="#+id/btnSubscribe"
android:layout_width="match_parent"
android:layout_height="45dp"
android:layout_marginTop="15dp"
android:layout_marginStart="20dp"
android:layout_below="#id/tvSubscribe"
android:layout_marginEnd="20dp"
android:text="#string/subscribe"
android:textColor="#color/white" />
</RelativeLayout>
and the
RecyclerView Adapter
public void onBindViewHolder(#NonNull final ReadViewholder, final int position) {
holder.readMoreButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (userIsSubscribed) {
//Launch the next Activity
} else {
//Show the subscribe layout
holder.rlSubscribeToView .setVisibility(View.VISIBLE);
//Then hide the entire recyvlerView
}
}
});
}
class ReadViewholder extends RecyclerView.ViewHolder {
RelativeLayout rlSubscribeToView;
Button readMoreButton;
ReadViewholder(#NonNull View itemView) {
super(itemView);
//Not able to find (rlSubscribeToView ) since its not inside the recyclerview
rlSubscribeToView = itemView.findViewById(R.id.rlSubscribeToView);
readMoreButton= itemView.findViewById(R.id.readMoreButton);
}
}
How can I get access to the subscribe layout (rlSubscribeToView), which is on the same layout file as the recycler view and also hide the entire recycler view in the Adapter?

From a little bit of research, the are 2 callbacks that get can get you a reference to the actual RecyclerView, the onAttachedToRecyclerView and the onDetachedFromRecycler methods. My guess is that you are calling the Adapter constructor and passing in a context. If so use the below code, it will produce your desired result.
RelativeLayout rlSubscribeToView;
RecyclerView recyclerView;
public RecyclerAdapter(Context context) {
this.context = context;
this.videoItems = videoItems;
rlSubscribeToView = ((Activity) context).findViewById(R.id.rlSubscribeToView);
}
#Override
public void onAttachedToRecyclerView(#NonNull RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
this.recyclerView = recyclerView;
}
and in your onBindViewHolder you can now get access the subscribe layout
public void onBindViewHolder(#NonNull final ReadViewholder, final int position) {
...
rlSubscribeToView.setVisibility();
}

What you need is an interface passed in as a parameter when you create your Adapter.
Example:
class Adapter(private val actions: Actions) : RecyclerView.Adapter<ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
// Create ViewHolder
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
// Setup Binder
holder.readMoreButton.setOnClickListener(View.OnClickListener {
if (userIsSubscribed) {
actions.launchActivity() //Launch the next Activity
} else {
//Show the subscribe layout
holder.rlSubscribeToView.setVisibility(View.VISIBLE)
actions.hideRecylerView() //Then hide the entire recyclerView
}
})
}
}
internal interface Actions {
fun launchActivity()
fun hideRecylerView()
}