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How to display JSON data from Horizontal recycle view kotlin using MVP method

I hope is all well with you.
I have constructed my code and build according the MVP style as well pulling JSON data but when I run the the code the horizontal recycle view and the JSON data is not being displayed. I tried going through every line of code and watching other tutorials but still no results.
Here is below my main activity:
class ProductCategoryActivity : BaseMvpActivity<ProductCategoryActivityView, ProductCategoryActivityPresnter> (),
ProductCategoryActivityView, CategoryAdapter.onItemClickListener{
private lateinit var binding: FragmentProductCategoryBinding
val data :MutableList<CateogryResponse> = ArrayList()
val adapter= CategoryAdapter(data, this)
#Inject
lateinit var presenter: ProductCategoryActivityPresnter
#Inject
lateinit var progressDialog: ProgressDialog
override fun onCreateComponent() {
userComponent.plus(CategoryActivityModule(this)).inject(this)
}
override fun providePresenter(): ProductCategoryActivityPresnter {
return presenter
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = FragmentProductCategoryBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
presenter.fetchcatogries()
showdata(ArrayList())
}
override fun showError(message: String) {
}
override fun showProgress() {
}
override fun hideProgress() {
}
override fun showdata(data: ArrayList<CateogryResponse>) {
val layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
recyclerViewPrimary.layoutManager = layoutManager
recyclerViewPrimary.setHasFixedSize(true)
recyclerViewPrimary.adapter = adapter
for(i in data)
data.add(CateogryResponse("product"))
}
override fun onItemClick(position: Int) {
Toast.makeText(this, "Item $position clicked", Toast.LENGTH_SHORT).show()
val clickedItem = data[position]
adapter.notifyItemChanged(position)
}
}
Here is my presenter:
#ActivityScope
class ProductCategoryActivityPresnter #Inject constructor(
private val stringProvider: StringProvider,
#AndroidScheduler private val observeOnScheduler: Scheduler,
#IOScheduler private val subscribeOnScheduler: Scheduler,
private val getCategoryUseCase: CategoryUseCase
) : BasePresenter<ProductCategoryActivityView>() {
lateinit var catogriesservice: CategoryRepositoryImpl
val catogriesLoadError = MutableLiveData<Boolean>()
val loading = MutableLiveData<Boolean>()
var catogries: ArrayList<CateogryResponse> = arrayListOf()
override fun onCreatePresenter(savedInstanceState: Bundle?) {
}
override fun onSaveInstanceState(outState: Bundle?) {
}
override fun onLoadData(arguments: Bundle?) {
fetchcatogries()
}
fun fetchcatogries() {
getCategoryUseCase.execute()
.observeOn(observeOnScheduler)
.subscribeOn(subscribeOnScheduler)
.subscribe(
SingleRequestSubscriber(
{
it
if (it != null && it.size > 0) {
catogries.removeAll(catogries)
catogries.addAll(it)
}
},
onFailure = { appException ->
view?.showError(
ErrorHandler.getErrorMessage(
appException,
stringProvider
)
)
},
onApiError = { apiException ->
view?.showError(
ErrorHandler.getErrorMessage(
apiException,
stringProvider
)
)
},
onAuthenticationError = { requestxception ->
view?.showError(
ErrorHandler.getErrorMessage(
requestxception,
stringProvider
)
)
},
onShowProgress = {
if (it) {
view?.showProgress()
} else {
view?.hideProgress()
}
},
onSubscribed = {
disposable.add(it)
})
)
}
}
Here is my view:
interface ProductCategoryActivityView {
fun showError(message: String)
fun showProgress()
fun hideProgress()
fun showdata ( data: ArrayList<CateogryResponse>)
}
Here is my adapter:
class CategoryAdapter(
private val data: List<CateogryResponse>,
private val listener: onItemClickListener
) : RecyclerView.Adapter<CategoryAdapter.ViewHolder>() {
private val items: MutableList<CardView>
init {
this.items = ArrayList()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val v = LayoutInflater.from(parent.context)
.inflate(R.layout.fragment_category_adapter, parent, false)
return ViewHolder(v)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.tvTitle.text = data[position].product
items.add(holder.card)
}
override fun getItemCount(): Int {
return data.size
}
inner class ViewHolder(itemView: View
) : RecyclerView.ViewHolder(itemView),
View.OnClickListener {
val tvTitle: TextView = itemView.featured_title
val card: CardView = itemView.CardView
init {
itemView.setOnClickListener(this)
}
override fun onClick(v: View?) {
val position: Int = adapterPosition
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position)
}
}
}
interface onItemClickListener {
fun onItemClick(position: Int)
}
}
Image:
Fragment Category Adapter:
android:id="#+id/CardView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
app:cardCornerRadius="2dp"
app:cardElevation="8dp">
<!-- We Will Add here the card & ImageViews -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="15dp">
<ImageView
android:id="#+id/featured_image"
android:layout_width="match_parent"
android:layout_height="140dp"
android:scaleType="centerCrop" />
<TextView
android:id="#+id/featured_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:lineHeight="23dp"
android:text="Chairs"
android:textColor="#color/colorAccent"
android:textSize="20sp" />
<TextView
android:id="#+id/featured_desc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="asbkd asudhlasn saudnas jasdjasl hisajdl asjdlnas" />
</LinearLayout>
</androidx.cardview.widget.CardView>
Fragment Product Category:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="#fafcfe"
tools:context="ui.category.ProductCategoryActivity">
<ImageView
android:id="#+id/imageView3"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/constraintLayout"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginTop="48dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="#+id/imageView"
app:layout_constraintTop_toTopOf="parent">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerViewPrimary"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:layout_marginTop="20dp"
android:text="#string/topselling"
android:textSize="18sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/constraintLayout" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/constraintLayout2"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:layout_marginTop="16dp"
app:layout_constraintBottom_toTopOf="#+id/imageView3"
app:layout_constraintEnd_toEndOf="#+id/constraintLayout"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerViewSecondary"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<ImageView
android:id="#+id/imageView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="32dp"
app:layout_constraintBottom_toBottomOf="#+id/imageView3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
/>
<TextView
android:id="#+id/textViewCategories"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="48dp"
android:layout_marginTop="20dp"
android:layout_marginBottom="15dp"
android:text="#string/catogries"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="#+id/constraintLayout"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteX="39dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
Not sure what went wrong.
If someone can point it out or show me what needs to be done to be able to display the data in horzintal recycle view, I would be really thanlful

You should update your recycler view adapter once your fetch call is executed, not before it ends.
Modify your fetchcatogries declaration so it accepts a callback method, which will be executed after the data are loaded.
This method will accept a list object as a parameter, which you will manage in your ProductCategoryActivity to populate the RecyclerView.
fun fetchcatogries(callback: (MutableList<CateogryResponse>) -> Unit) {
getCategoryUseCase.execute()
.observeOn(observeOnScheduler)
.subscribeOn(subscribeOnScheduler)
.subscribe(
SingleRequestSubscriber(
{ categories ->
callback(categories)
},
...
)
}
You can now edit your onCreate and showdata methods in ProductCategoryActivity like this:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = FragmentProductCategoryBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
presenter.fetchcatogries { categories ->
showdata(categories as ArrayList<CateogryResponse>)
}
}
override fun showdata(data: ArrayList<CateogryResponse>) {
val layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
recyclerViewPrimary.layoutManager = layoutManager
recyclerViewPrimary.setHasFixedSize(true)
recyclerViewPrimary.adapter = CategoryAdapter(data.toList(), this)
}

How can I update the UI without skipping frames

So I am developing and android app in Kotlin with coroutines and no matter what change I make, I still keep getting the message:
I/Choreographer: Skipped 59 frames! The application may be doing too much work on its main thread.
How can I get rid of it. I mean like I am only displaying nine photos... Below is my code
Model:
data class Food (
val id: String,
val name: String,
val price: String,
#Json(name = "img_url") val imgSrcUrl: String,
val type: String,
val description: String,
val average_rating: String,
val number_of_raters: String,
val special_price: String
)
data class FoodCategory(
val id: String,
val title: String,
val foods: List<Food>
)
ViewModel:
enum class NetworkStatus {LOADING, DONE, FAILED}
enum class FontFamily (#FontRes val fontRes: Int) {
POPPINS_BOLD(R.font.poppins_bold),
POPPINS(R.font.poppins)
}
class FoodOverviewViewModel(private val foodRepository: FoodRepository): ViewModel() {
private lateinit var foodProducts: List<Food>
//This is the data that is gonna be exposed to the viewmodel
//It will be submitted to a ListAdapter
private val _foodCategory = MutableLiveData<List<FoodCategory>>()
val foodCategory: LiveData<List<FoodCategory>>
get() = _foodCategory
//Used to display a progress bar for network status
private val _status = MutableLiveData<NetworkStatus>()
val status: LiveData<NetworkStatus>
get() = _status
init {
getOverviewProducts()
}
private fun getOverviewProducts() {
viewModelScope.launch(Dispatchers.Default) {
_status.postValue(NetworkStatus.LOADING)
try {
getUpdatedFood()
Log.i("getOverviewProducts","I am running on tread: $coroutineContext")
_status.postValue(NetworkStatus.DONE)
}catch (e: Exception) {
_status.postValue(NetworkStatus.FAILED)
}
}
}
private suspend fun getUpdatedFood() {
//withContext(Dispatchers.Default) {
val limiter = 6 //Number of items I want to get from the server
val foodCategory = arrayListOf<FoodCategory>()
Log.i("getUpdatedFood","I am running on tread: $coroutineContext")
val getRecommended = foodRepository.getRecommendedFood(limiter.toString())
foodCategory += FoodCategory(id = 0.toString(), title = "Recommended for you", foods = getRecommended)
val getSpecials = foodRepository.getSpecials(limiter.toString())
foodCategory += FoodCategory(id = 1.toString(), title = "Specials", foods = getSpecials)
_foodCategory.postValue(foodCategory)
//}
}
}
Repository:
class FoodRepository {
suspend fun getRecommendedFood(limiter: String) = withContext(Dispatchers.IO) {
Log.i("Resp-getRecommended","I am running on tread: $coroutineContext")
return#withContext ProductApi.retrofitService.getRecommended(limiter)
}
suspend fun getSpecials(limiter: String) = withContext(Dispatchers.IO) {
Log.i("Resp-getSpecials","I am running on tread: $coroutineContext")
return#withContext ProductApi.retrofitService.getSpecials(limiter)
}
}
BindingAdapters:
//Load image using Glide (in Food item recycleview)
#BindingAdapter("imageUrl")
fun bindImage(imgView: ImageView , imgUrl: String?) {
imgUrl?.let {
val imgUri = imgUrl.toUri().buildUpon().scheme("http").build()
Glide.with(imgView.context)
.load(imgUri)
.apply(
RequestOptions()
.placeholder(R.drawable.loading_animation)
.error(R.drawable.ic_broken_image))
.into(imgView)
}
}
//set raters count (in Food item recycleview)
#BindingAdapter("ratersCount")
fun bindText(txtView: TextView, number_of_raters: String?) {
number_of_raters?.let {
val ratersCount = "(${number_of_raters})"
txtView.text = ratersCount
}
}
//update the progressbar visibilty (in outer-parent recycleview)
#BindingAdapter("updateStatus")
fun ProgressBar.updateStatus(status: NetworkStatus?) {
visibility = when (status) {
NetworkStatus.LOADING -> View.VISIBLE
NetworkStatus.DONE -> View.GONE
else -> View.GONE
}
}
//Hide or view an imageview based in the network Status. When network Error, an error image
//will show (in outer-parent recycleview)
#BindingAdapter("setNoInternet")
fun ImageView.setNoInternet(status: NetworkStatus?) {
when(status) {
NetworkStatus.LOADING -> {
visibility = View.GONE
}
NetworkStatus.DONE -> {
visibility = View.GONE
}
NetworkStatus.FAILED -> {
visibility = View.VISIBLE
setImageResource(R.drawable.ic_connection_error)
}
}
}
//Submit the list of FoodCatergory item to the outer-parent recycleview
#BindingAdapter("listData")
fun bindRecyclerView(recyclerView: RecyclerView, data: List<FoodCategory>?) {
(recyclerView.adapter as FoodCategoryAdapter).submitList(data)
}
//Submit list the the Food item recyclew view (child recycleView)
#BindingAdapter("setProducts")
fun RecyclerView.setProducts(foods: List<Food>?) {
if (foods != null) {
val foodAdapter = FoodItemAdapter()
foodAdapter.submitList(foods)
adapter = foodAdapter
}
}
I have a Recycleview of Food Item and a Recycleview Pool of FoodCategory. If I comment out
_foodCategory.postValue(foodCategory)
in ViewModel: getUpdatedFood() than I do not get the message. However, when I submit the list to the outer recycleview (The one the hold the viewpool), than I get this answer. Please help. I been stuck on it for a while tryna get rid of that message.
Thank you..
Updated
Below is the adapeters and its view holders
FoodItem layout
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<import type="android.view.View"/>
<variable
name="foodItem"
type="com.example.e_commerceapp.models.Food"/>
<variable
name="font"
type="com.example.e_commerceapp.products.overview.FontFamily"/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/child_item_main_layout"
android:background="#drawable/search_background"
android:layout_marginTop="10dp"
android:layout_marginStart="10dp"
android:layout_marginBottom="10dp"
android:layout_width="150dp"
android:layout_height="250dp">
<ImageView
android:layout_width="120dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:id="#+id/burger_image"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_height="160dp"
/>
<!-- app:imageUrl="#{foodItem.imgSrcUrl}"-->
<TextView
android:layout_width="match_parent"
android:layout_height="34dp"
android:layout_marginStart="5dp"
android:id="#+id/burger_title"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginEnd="5dp"
android:singleLine="true"
android:textColor="#B4000000"
app:layout_constraintTop_toBottomOf="#id/burger_image"
android:text="#{foodItem.name}"
android:textSize="12sp"
android:fontFamily="#font/poppins"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="35dp"
app:layout_constraintTop_toBottomOf="#id/burger_title"
android:layout_marginEnd="5dp"
android:gravity="center"
android:id="#+id/burger_price"
android:layout_marginStart="5dp"
app:layout_constraintStart_toEndOf="#id/special_price"
android:textColor="#D0000000"/>
<!-- app:price="#{foodItem.price}"-->
<!-- app:specialPrice="#{foodItem.special_price}"-->
<!-- app:fontRes="#{foodItem.special ? font.POPPINS : font.POPPINS_BOLD}"-->
<TextView
android:layout_width="wrap_content"
android:layout_height="35dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/burger_title"
android:layout_marginEnd="5dp"
android:gravity="center_vertical"
android:layout_marginStart="5dp"
android:id="#+id/special_price"
android:textColor="#D0000000"
android:visibility="gone"
android:textStyle="normal"
android:fontFamily="#font/poppins_bold"/>
<!-- app:setSpecialPrice="#{foodItem.special_price}"-->
<ImageView
android:layout_width="15dp"
android:layout_height="15dp"
app:layout_constraintTop_toBottomOf="#id/burger_price"
android:src="#drawable/ic_baseline_star_24"
android:visibility="#{foodItem.hasRating ? View.GONE : View.VISIBLE}"
android:id="#+id/rating_star"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="5dp"
android:layout_marginBottom="10dp"
app:layout_constraintBottom_toBottomOf="parent"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="15dp"
android:layout_marginStart="5dp"
android:gravity="center"
android:textSize="12sp"
android:visibility="#{foodItem.hasRating ? View.GONE : View.VISIBLE}"
android:id="#+id/rating_count"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="#id/burger_price"
android:text="#{foodItem.average_rating}"
android:layout_marginBottom="10dp"
app:layout_constraintStart_toEndOf="#id/rating_star"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="15dp"
android:id="#+id/number_of_raters"
android:textSize="12sp"
android:visibility="#{foodItem.hasRating ? View.GONE : View.VISIBLE}"
android:layout_marginStart="2dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="#id/rating_count"
app:ratersCount="#{foodItem.number_of_raters}"
android:layout_marginBottom="10dp"
app:layout_constraintTop_toBottomOf="#id/burger_price"/>
<ImageView android:layout_width="20dp"
android:layout_height="20dp"
android:layout_marginEnd="10dp"
android:layout_marginTop="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
FoodItem Adapter
class FoodItemAdapter: ListAdapter<Food ,
FoodItemAdapter.ItemFoodViewHolder>(DiffCallback) {
override fun onCreateViewHolder(parent: ViewGroup , viewType: Int): ItemFoodViewHolder {
return ItemFoodViewHolder(
FoodItemBinding.inflate(LayoutInflater.from(parent.context),
parent, false))
}
override fun onBindViewHolder(holder: ItemFoodViewHolder , position: Int) {
val currentFood = getItem(position)
holder.bind(currentFood)
}
class ItemFoodViewHolder(private var binding: FoodItemBinding): RecyclerView.ViewHolder(binding.root) {
fun bind(food: Food) {
binding.foodItem = food
binding.executePendingBindings()
}
}
object DiffCallback: DiffUtil.ItemCallback<Food>() {
override fun areItemsTheSame(oldItem: Food , newItem: Food): Boolean {
return oldItem === newItem
}
override fun areContentsTheSame(oldItem: Food , newItem: Food): Boolean {
return oldItem.id == newItem.id
}
}
}
FoodCategory layout
<?xml version="1.0" encoding="utf-8"?>
<layout 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">
<data>
<variable
name="foodCategory"
type="com.example.e_commerceapp.models.FoodCategory"/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:background="#fff"
android:layout_marginTop="5dp"
android:layout_marginBottom="5dp"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:id="#+id/category_title"
android:layout_marginTop="16dp"
android:text="#{foodCategory.title}"
android:textColor="#2B2A2A"
android:fontFamily="#font/poppins_bold"
android:textSize="16sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/nestedRecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
app:setProducts="#{foodCategory.foods}"
android:orientation="horizontal"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/category_title"
tools:itemCount="4"
tools:listitem="#layout/food_item"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
FoodCategory Adapter
class FoodCategoryAdapter: ListAdapter<FoodCategory,
FoodCategoryAdapter.CategoryFoodViewHolder>(Companion) {
private val viewPool = RecyclerView.RecycledViewPool()
override fun onCreateViewHolder(parent: ViewGroup , viewType: Int): CategoryFoodViewHolder {
return CategoryFoodViewHolder(FoodCategoryBinding.inflate(LayoutInflater.from(parent.context),
parent, false))
}
override fun onBindViewHolder(holder: CategoryFoodViewHolder , position: Int) {
val currentFoodCategory = getItem(position)
holder.bind(currentFoodCategory)
}
inner class CategoryFoodViewHolder(private var binding: FoodCategoryBinding): RecyclerView.ViewHolder(binding.root) {
fun bind(currentFoodCategory: FoodCategory?) {
binding.foodCategory = currentFoodCategory
binding.nestedRecyclerView.setRecycledViewPool(viewPool)
binding.executePendingBindings()
}
}
companion object: DiffUtil.ItemCallback<FoodCategory>() {
override fun areItemsTheSame(oldItem: FoodCategory , newItem: FoodCategory): Boolean {
return oldItem === newItem
}
override fun areContentsTheSame(oldItem: FoodCategory, newItem: FoodCategory): Boolean {
return oldItem.id == newItem.id
}
}
}
The parent recycleView
<?xml version="1.0" encoding="utf-8"?>
<layout 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"
tools:context=".products.overview.FoodOverviewFragment">
<data>
<variable
name="foodOverview"
type="com.example.e_commerceapp.products.overview.FoodOverviewViewModel"/>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:background="#color/grey"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:id="#+id/relative_layout"
android:layout_height="105dp"
android:elevation="8dp"
android:layout_marginBottom="5dp"
android:background="#fff"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent">
<ImageView
android:layout_width="200dp"
android:layout_marginTop="10dp"
android:layout_height="35dp"
android:id="#+id/logo_and_name"
android:src="#drawable/compony_logo_and_name"
android:layout_alignParentStart="true"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="35dp"
android:layout_marginTop="10dp"
android:id="#+id/notifications"
android:src="#drawable/ic_baseline_notifications_24"
android:layout_alignParentEnd="true"
android:paddingEnd="20dp"
android:paddingStart="20dp"/>
<TextView
android:layout_width="match_parent"
android:id="#+id/search"
android:layout_marginTop="10dp"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:background="#drawable/search_background"
android:layout_below="#id/logo_and_name"
android:gravity="center_vertical"
android:layout_height="match_parent"
android:layout_marginBottom="10dp"
android:paddingEnd="10dp"
android:paddingStart="10dp"
android:text="#string/search_text"
tools:ignore="RtlSymmetry"
app:drawableEndCompat="#drawable/ic_baseline_search_24"/>
</RelativeLayout>
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:updateStatus="#{foodOverview.status}"
app:layout_constraintTop_toBottomOf="#id/relative_layout"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:id="#+id/progressbar"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/relative_layout"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:id="#+id/noInternetImage"/>
<androidx.recyclerview.widget.RecyclerView
android:layout_width="0dp"
android:id="#+id/foodCategory"
android:clipToPadding="false"
tools:itemCount="4"
tools:listitem="#layout/food_category"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
android:layout_height="0dp"
app:listData="#{foodOverview.foodCategory}"
app:layout_constraintTop_toBottomOf="#id/relative_layout"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

The skipping frames likely has nothing to do with the code you posted: it sounds like a misconfiguration of RecyclerViews / Adapters to me. You'll need to post that code for it be more clear though.
However, even though what you posted likely isn't the culprit you can still optimize the coroutines code you have:
class FoodOverviewViewModel(private val foodRepository: FoodRepository): ViewModel() {
private lateinit var foodProducts: List<Food>
private val _foodCategory = MutableLiveData<List<FoodCategory>>()
val foodCategory: LiveData<List<FoodCategory>>
get() = _foodCategory
private val _status = MutableLiveData<NetworkStatus>()
val status: LiveData<NetworkStatus>
get() = _status
init {
getOverviewProducts()
}
private fun getOverviewProducts() {
viewModelScope.launch { // <------- Don't apply a custom scope here
_status.value = NetworkStatus.LOADING // <--- Don't call "postValue" here
try {
val food = getUpdatedFood() // <------ This is already using a background dispatcher
_foodCategory.value = food // <------- Emit this value here
_status.value = NetworkStatus.DONE
} catch (e: Exception) {
_status.value = NetworkStatus.FAILED
}
}
}
private suspend fun getUpdatedFood(): List<FoodCategory> { // <---- Return a value here
val limiter = 6 //Number of items I want to get from the server
val foodCategory = arrayListOf<FoodCategory>()
Log.i("getUpdatedFood","I am running on tread: $coroutineContext")
val getRecommended = foodRepository.getRecommendedFood(limiter.toString())
foodCategory += FoodCategory(id = 0.toString(), title = "Recommended for you", foods = getRecommended)
val getSpecials = foodRepository.getSpecials(limiter.toString())
foodCategory += FoodCategory(id = 1.toString(), title = "Specials", foods = getSpecials)
return foodCategories
}
}
The key ideas here:
Use viewModelScope.launch { ... } rather than applying a scope. You want everything in there that is not a coroutine to run on the main thread. See, for example, https://developer.android.com/kotlin/coroutines/coroutines-best-practices#main-safe
Return a value from getUpdatedFood so you can just update the _foodCategory value on the main thread in the viewModelScope

Kotlin Recyclerview row item selection background color change

I am able to change the color of the text and background of row clicked of my recyclerview in my recyclerview.
But my problem is after clicking for example on the 2th item,the 10st item also gets selected.Likewise after clicking my 5th item the 3nd item is selected.
How do i solve this?
in fact my question is that how to change background color of recyclerview item that click on it in Kotlin?
I also followed the instructions in this link. But it did not worked correctly!!
AllChanelAdapter.kt
class AllChanelAdapter(private val datalist:MutableList<AllChanelModel>, var clickListener: OnItemClickListener):RecyclerView.Adapter<AllChanelHolder>() {
private lateinit var context:Context
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AllChanelHolder {
context = parent.context
return AllChanelHolder(LayoutInflater.from(context).inflate(R.layout.allchanel_singleitem,parent,false))
}
override fun getItemCount(): Int = datalist.size
override fun onBindViewHolder(holder: AllChanelHolder, position: Int) {
val data = datalist[position]
val txt_title = holder.itemView.txt_title
val txt_body = holder.itemView.txt_body
val img_chanel = holder.itemView.img_chanel
txt_title.setText(data.title)
txt_body.setText(data.body)
Glide
.with(context)
.load("...")
.centerCrop()
.into(img_chanel);
}
holder.initialize(datalist.get(position),clickListener)
}
interface OnItemClickListener {
fun onItemClick(item: AllChanelModel, position: Int, view: View)
}
AllChanelHolder.kt
class AllChanelHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
fun initialize(item:AllChanelModel,action:OnItemClickListener){
itemView.setOnClickListener {
action.onItemClick(item,adapterPosition,itemView)
}
}
}
MainPageActivity.kt
class MainPageActivity : AppCompatActivity(),OnItemClickListener {
private val datalist:MutableList<AllChanelModel> = mutableListOf()
lateinit var allchaneladapter : AllChanelAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main_page)
send_request()
allchaneladapter = AllChanelAdapter(datalist,this)
all_chanel_recycler.layoutManager = LinearLayoutManager(this)
all_chanel_recycler.adapter = allchaneladapter
}
private fun send_request(){
val url = "http://10.0.2.2:8000/getsamplejson" // localhost api
val que = Volley.newRequestQueue(this#MainPageActivity)
val req = JsonArrayRequest(Request.Method.GET,url,null,
Response.Listener {
response->
for(i in 0..response.length()-1){
var chanel_obj = response.getJSONObject(i)
datalist.add(
AllChanelModel(
chanel_obj.getString("body"),
chanel_obj.getString("title"),
chanel_obj.getString("userId")
)
)
}
allchaneladapter.notifyDataSetChanged()
}, Response.ErrorListener {
error->
Log.e("",error.message)
})
que.add(req)
}
override fun onItemClick(item: AllChanelModel, position: Int, view: View) {
view.setBackgroundColor(Color.YELLOW)
}
}
AllChanelModel.kt
data class AllChanelModel(
#SerializedName("body")
val body: String,
#SerializedName("title")
val title: String,
#SerializedName("userId")
val userId: String
)
activity_main_page.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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"
tools:context=".MainPageActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/all_chanel_recycler"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
allchanel_singleitem.xml
<?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"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout
android:id="#+id/linear_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="3"
android:orientation="vertical"
android:padding="5dp">
<TextView
android:id="#+id/txt_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:text="TextView"
android:textColor="#000000" />
<TextView
android:id="#+id/txt_body"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center|right"
android:text="TextView"
android:textColor="#000000" />
</LinearLayout>
<ImageView
android:id="#+id/img_chanel"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_weight="1"
app:srcCompat="#mipmap/ic_launcher" />
</LinearLayout>
please help me
thank you

After a thorough search on the Internet, I was finally able to solve this problem.
I put the code step by step and give explanations if needed.
1 - create new android studio project
2 - cods for activity_main.xml as below:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainPageActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:drawable/screen_background_light_transparent"
tools:listitem="#layout/item_list" />
</androidx.constraintlayout.widget.ConstraintLayout>
3 - create a layout for recycler view row(item) with name item_list.xml as bellow
item_list.xml
<?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"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout
android:id="#+id/linear_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="3"
android:background="#FFFFFF"
android:orientation="vertical"
android:padding="5dp">
<TextView
android:id="#+id/tv_label"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:text="TextView"
android:textColor="#000000" />
<TextView
android:id="#+id/tv_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center|right"
android:text="TextView"
android:textColor="#000000" />
</LinearLayout>
<ImageView
android:id="#+id/img_chanel"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_weight="1"
app:srcCompat="#mipmap/ic_launcher" />
</LinearLayout>
4 - create data class(Based on the data you want to bind in RecyclerView) as bellow
My Model(UserModel.kt)
public data class UserModel(var title:String,var name:String,var isSelected:Boolean=false)
5 - create Adapter for your RecyclerView as bellow
CustomAdapter.kt
class CustomAdapter(private val context: Context, private val list: ArrayList<UserModel>,
private val listener: OnItemClickListener
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private inner class ViewHolder internal constructor(itemView: View) : RecyclerView.ViewHolder(itemView),View.OnClickListener {
internal var tvLabel: TextView
internal var tvName: TextView
init {
tvLabel = itemView.findViewById(R.id.tv_label) // Initialize your All views prensent in list items
tvName = itemView.findViewById(R.id.tv_name) // Initialize your All views prensent in list items
itemView.setOnClickListener(this)
}
internal fun bind(position: Int) {
// This method will be called anytime a list item is created or update its data
//Do your stuff here
tvLabel.text = list[position].title
tvName.text = list[position].name
}
override fun onClick(v: View?) {
val position:Int = adapterPosition
if(position != RecyclerView.NO_POSITION) {
listener.onItemClick(position,this#CustomAdapter,itemView)
}
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return ViewHolder(LayoutInflater.from(context).inflate(R.layout.item_list, parent, false))
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
if(list[position].isSelected){
holder.itemView.setBackgroundColor(Color.YELLOW)
holder.itemView.findViewById<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.YELLOW)
} else{
holder.itemView.setBackgroundColor(Color.WHITE)
holder.itemView.findViewById<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.WHITE)
}
(holder as ViewHolder).bind(position)
}
override fun getItemCount(): Int {
return list.size
}
interface OnItemClickListener{
fun onItemClick(position: Int,adapter:CustomAdapter,v:View)
}
}
6 - codes for MainActivity.kt as bellow:
MainActivity.kt
class MainActivity : AppCompatActivity(),CustomAdapter.OnItemClickListener {
private val data = arrayListOf<UserModel>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main_page)
val recyclerview = findViewById<RecyclerView>(R.id.recycler_view)
data.add(UserModel(title = "item 1",name = "name 1"))
data.add(UserModel(title = "item 2",name = "name 2"))
data.add(UserModel(title = "item 3",name = "name 3"))
data.add(UserModel(title = "item 4",name = "name 4"))
data.add(UserModel(title = "item 5",name = "name 5"))
data.add(UserModel(title = "item 6",name = "name 6"))
data.add(UserModel(title = "item 1",name = "name 1"))
data.add(UserModel(title = "item 2",name = "name 2"))
data.add(UserModel(title = "item 3",name = "name 3"))
data.add(UserModel(title = "item 4",name = "name 4"))
data.add(UserModel(title = "item 5",name = "name 5"))
data.add(UserModel(title = "item 6",name = "name 6"))
val adapter = CustomAdapter(this,data,this)
recyclerview.layoutManager = LinearLayoutManager(this)
recyclerview.adapter = adapter
recyclerview.setHasFixedSize(true)
}
override fun onItemClick(position: Int,adapter: CustomAdapter,v:View) {
val clicked_item:UserModel = data[position]
clicked_item.title = "clicked"
clicked_item.isSelected = !clicked_item.isSelected
if(clicked_item.isSelected){
recycler_view.getChildAt(recycler_view.indexOfChild(v)).setBackgroundColor(Color.YELLOW)
recycler_view.getChildAt(recycler_view.indexOfChild(v)).findViewById<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.YELLOW)
}else{
recycler_view.getChildAt(recycler_view.indexOfChild(v)).setBackgroundColor(Color.WHITE)
recycler_view.getChildAt(recycler_view.indexOfChild(v)).findViewById<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.WHITE)
}
}
}
I hope you find it useful

You have to set color for other items when you cal

Trying to display an entire collection from my Firestore database using RecyclerView and Fragments - Kotlin

I have tried many different tutorials and haven't been able to relate any to my application. My application in a gist displays a user's medication that they are taking. Here is my data class...
import java.util.HashMap
class LocalMedication {
var m_medicationName: String? = null
var m_medicationQty: String? = null
var m_medicationType: String? = null
var m_medicationExpDate: String? = null
var m_medicationStatus: Boolean = false
constructor() {}
constructor(medicationName: String, medicationQty: String, medicationType: String, medicationExpDat : String, medicationStatus : Boolean) {
this.m_medicationName = medicationName
this.m_medicationType = medicationType
this.m_medicationQty = medicationQty
this.m_medicationExpDate = medicationExpDat
this.m_medicationStatus = medicationStatus
}
fun toMap(): Map<String, Any> {
val result = HashMap<String, Any>()
result.put("medicationName", m_medicationName!!)
result.put("medicationType", m_medicationType!!)
result.put("medicationQty", m_medicationQty!!)
result.put("medicationExpDate", m_medicationExpDate!!)
result.put("medicationStatus", m_medicationStatus!!)
return result
}
}
Here is my view holder class
package com.example.home_med.viewHolder
import android.view.View
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.example.home_med.R
class medicationViewHolder(view: View) : RecyclerView.ViewHolder(view) {
var medicationName: TextView
var medicationType: TextView
var medicationQty: TextView
init {
medicationName = view.findViewById(R.id.rv_medicationName)
medicationType = view.findViewById(R.id.rv_medicationType)
medicationQty = view.findViewById(R.id.rv_medicationQty)
}
}
Here is my fragment
class LocalMedication : Fragment() {
private var adapter: FirestoreRecyclerAdapter<LocalMedication, medicationViewHolder>? = null
private var firestoreDB: FirebaseFirestore? = null
private var firestoreListener: ListenerRegistration? = null
private var medList = mutableListOf<LocalMedication>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
//setContentView(R.layout.activity_main)
firestoreDB = FirebaseFirestore.getInstance()
val recyclerView = recyclerview as? RecyclerView
val mLayoutManager = LinearLayoutManager(context)
recyclerView?.layoutManager = mLayoutManager
recyclerView?.itemAnimator = DefaultItemAnimator()
loadMedication()
firestoreListener = firestoreDB!!.collection("notes")
.addSnapshotListener(EventListener { documentSnapshots, e ->
if (e != null) {
Log.e(TAG, "Listen failed!", e)
return#EventListener
}
medList = mutableListOf()
if (documentSnapshots != null) {
for (doc in documentSnapshots) {
val note = doc.toObject(LocalMedication::class.java)
note.m_medicationName = doc.id
medList.add(note)
}
}
adapter!!.notifyDataSetChanged()
recyclerView?.adapter = adapter
})
}
override fun onDestroy() {
super.onDestroy()
firestoreListener!!.remove()
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val binding: FragmentLocalMedicationBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_local_medication, container, false)
binding.viewMedicationButton.setOnClickListener { v: View ->
v.findNavController().navigate(LocalMedicationDirections.actionLocalMedicationToViewMedication())
}
binding.addMedicationButton.setOnClickListener { v: View ->
v.findNavController().navigate(LocalMedicationDirections.actionLocalMedicationToAddMedication())
}
binding.homeButton.setOnClickListener { v: View ->
v.findNavController().navigate(LocalMedicationDirections.actionLocalMedicationToHome2())
}
setHasOptionsMenu(true)
return binding.root
}
private fun loadMedication() {
val query = firestoreDB!!.collection("notes")
val response = FirestoreRecyclerOptions.Builder<LocalMedication>()
.setQuery(query, LocalMedication::class.java)
.build()
adapter = object : FirestoreRecyclerAdapter<LocalMedication, medicationViewHolder>(response) {
override fun onBindViewHolder(holder: medicationViewHolder, position: Int, model: LocalMedication) {
val note = medList[position]
holder.medicationName.text = note.m_medicationName
holder.medicationType.text = note.m_medicationType
holder.medicationQty.text = note.m_medicationQty
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): medicationViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.recyclerview_item, parent, false)
return medicationViewHolder(view)
}
override fun onError(e: FirebaseFirestoreException) {
Log.e("error", e!!.message)
}
}
adapter!!.notifyDataSetChanged()
recyclerview?.adapter = adapter
}
public override fun onStart() {
super.onStart()
adapter!!.startListening()
}
public override fun onStop() {
super.onStop()
adapter!!.stopListening()
}
}
Here is my recyclerViewItem XML file
<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:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/rv_medicationName"
style="#style/word_title"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:background="#android:color/holo_orange_light"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/rv_medicationQty"
style="#style/word_title"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:background="#android:color/holo_orange_light"
app:layout_constraintStart_toEndOf="#+id/rv_medicationName"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/rv_medicationType"
style="#style/word_title"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:background="#android:color/holo_orange_light"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/rv_medicationQty"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
Here is my localMedications XML file
<layout 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"
tools:context=".LocalMedication">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="32dp"
android:layout_marginBottom="32dp"
android:text="LOCAL MEDICATION"
android:textSize="36sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.478"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="543dp"
android:layout_height="0dp"
android:layout_marginTop="16dp"
android:layout_marginBottom="16dp"
android:background="#android:color/darker_gray"
app:layout_constraintBottom_toTopOf="#+id/homeButton"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView"
tools:listitem="#layout/recyclerview_item" />
<Button
android:id="#+id/viewMedicationButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="100dp"
android:layout_marginBottom="100dp"
android:text="View Med"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<Button
android:id="#+id/addMedicationButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="100dp"
android:layout_marginBottom="100dp"
android:text="Add Medication"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/homeButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="30dp"
android:layout_marginTop="59dp"
android:layout_marginEnd="30dp"
android:layout_marginBottom="103dp"
android:text="Home"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#+id/viewMedicationButton"
app:layout_constraintStart_toEndOf="#+id/addMedicationButton"
app:layout_constraintTop_toBottomOf="#+id/addMedicationButton"
app:layout_constraintVertical_bias="0.972" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
Here is what my database looks like...
Datatbase
Any help or guidance would be great. It runs the application, but in the Logs, it says "RecyclerView: No adapter attached; skipping layout"

The problem in your code lies in the fact that the names of the fields in your LocalMedication class are different than the name of the properties in your database. You have in your LocalMedication class a field named m_medicationName while in your database I see it as medicationName and this is not correct. The names must match. Behind the scene, Kotlin is creating a Java class with a getter named getM_medicationName() so Firebase is looking in the database for a field named m_medicationName and not medicationName.
There are two ways in which you can solve this problem. The first one would be to remove the data in your database and add it again using field names (m_medicationName, m_medicationQty etc) that exist in your LocalMedication class.
If you are not allowed to use the first solution, then the second approach will be to use annotations in front of your public fields. So you should use the PropertyName annotation in front of every field. So in your LocalMedication class, a field should look like this:
#get:PropertyName("medicationName")
#set:PropertyName("medicationName")
public var m_medicationName: String? = null
As explained in my answer from the following post:
I am trying to get the correct reference to my Firebase Database child and set the values in my RecyclerView but I am having some issues
It's for Firebase realtime database but the same rules apply to Cloud Firestore.

How to change my existing code by integrating data binding android

I have an exisitng code which I integrate with Live data by using retrofit.
Now if I want to integrate databinding, where are all changes to be done to make the code looks perfect?
Here is my code.
activity_main.xml:
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:background="#000000"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Android Versions"
android:textColor="#ffffff"
android:textSize="20sp" />
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
items.xml:
<?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:background="#445566"
android:layout_margin="5dp"
android:layout_height="wrap_content">
<TextView
android:id="#+id/tvFname"
android:padding="5dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top|start"
android:layout_marginTop="8dp"
android:textColor="#ffffff"
android:layout_weight="1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="#+id/tvLname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center|start"
android:padding="5dp"
android:layout_marginTop="10dp"
android:layout_weight="1"
android:ellipsize="end"
android:textColor="#ffffff"
android:maxLines="5"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvFname"/>
</android.support.constraint.ConstraintLayout>
Here is view model class which I integrated
class AndroidViewModel:ViewModel() {
private val mService = RetrofitService()
fun getAndroidData():MutableLiveData<List<AndroidData>>?{
return mService.loadAndroidData()
}
}
Pojo class generated is just a simple one:
data class AndroidData (val name:String, val apiLevel:String)
Service integration:
class RetrofitService {
val liveUserResponse:MutableLiveData<List<AndroidData>> = MutableLiveData()
companion object Factory {
var gson = GsonBuilder().setLenient().create()
fun create(): ApiInterface {
Log.e("retrofit","create")
val retrofit = Retrofit.Builder()
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create(gson))
.baseUrl("https://learn2crack-json.herokuapp.com/api/")
.build()
return retrofit.create(ApiInterface::class.java)
}
}
fun loadAndroidData(): MutableLiveData<List<AndroidData>>? {
Log.e("loadAndroidData","yes")
val retrofitCall = create().getAndroid()
retrofitCall.enqueue(object : Callback<List<AndroidData>> {
override fun onFailure(call: Call<List<AndroidData>>, t: Throwable?) {
Log.e("on Failure :", "retrofit error")
}
override fun onResponse(call: Call<List<AndroidData>>, response: retrofit2.Response<List<AndroidData>>) {
val list = response.body()
for (i in list.orEmpty()){
Log.e("on response 1:", i.name)
}
liveUserResponse.value = list
Log.e("hasActiveObservers 1", liveUserResponse.hasActiveObservers().toString()+" check")
Log.e("on response 2 :", liveUserResponse.toString()+" check")
}
})
return liveUserResponse
}
Main Activity:
class MainActivity : AppCompatActivity(){
private lateinit var linearLayoutManager: LinearLayoutManager
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
linearLayoutManager = LinearLayoutManager(this)
recyclerView.setHasFixedSize(true)
getAndroidVersion()
}
private fun getAndroidVersion() {
Log.e("getAndroidVersion", "yes")
val mAndroidViewModel = ViewModelProviders.of(this#MainActivity).get(AndroidViewModel::class.java)
mAndroidViewModel.getAndroidData()?.observe(this, Observer<List<AndroidData>> { androidList ->
Log.e("list", androidList?.size.toString())
recyclerView.adapter = EmpAdapter(this#MainActivity, androidList as ArrayList<AndroidData>, object :
ItemClickListener {
override fun onItemClick(pos: Int, name:String) {
Toast.makeText(applicationContext, "item "+pos+ "clicked"+ name, Toast.LENGTH_LONG).show()
}
})
})
}
}
Adapter class:
class EmpAdapter(
var context: MainActivity,
var mEmpList: ArrayList<AndroidData>,
private val itemClick:ItemClickListener
) :
RecyclerView.Adapter<EmpAdapter.EmpHolder>() {
override fun getItemCount(): Int {
return mEmpList.size
}
companion object {
var mItemClickListener : ItemClickListener? = null
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): EmpHolder {
val view = LayoutInflater.from(context).inflate(R.layout.items, parent, false)
return EmpHolder(view)
}
override fun onBindViewHolder(holder: EmpHolder, position: Int) {
mItemClickListener = itemClick
holder.tvFname?.text = mEmpList[position].name
holder.tvLname?.text = mEmpList[position].apiLevel
RxView.clicks(holder.mView).subscribe {
mItemClickListener!!.onItemClick(position,mEmpList[position].name)
}
}
class EmpHolder(view: View) : RecyclerView.ViewHolder(view) {
val tvFname = view.tvFname
val tvLname = view.tvLname
val mView = view
}
}
interfaces for retrofit:
interface ApiInterface {
#GET("android")
fun getAndroid(): Call<List<AndroidData>>
}
Now my question is, if I integrate tag and in xml, which variable i need to specify for textview to integrate to connect for textview in adapter? Kindly guide me where are all I need to change to apply, if I use live data

First of all, i strongly recommend to use a Retrofit Adapter that converts the response into LiveData automatically for you. See this example
https://github.com/yasiralijaved/android-architecture-components/blob/master/component_http/src/main/java/com/yasiralijaved/android/arc/component/http/BackendService.java
Secondly there are detailed tutorials out there which can surely help you how to implement Data Bindings in RecyclerView Adapter. A few tutorials are:
https://medium.com/androiddevelopers/android-data-binding-recyclerview-db7c40d9f0e4
https://android.jlelse.eu/how-to-bind-a-list-of-items-to-a-recyclerview-with-android-data-binding-1bd08b4796b4
Do let me know if it is still not clear and i will share some more details.
Happy coding!!