with limited understanding of the Kotlin programming language, I tried editing the code that was previously running normally. my goal is to add admob banner between the recycleview data that is already running well. I have tried it for 1 week or more and there have been no significant results, please help so that the Admob banner function can run properly on the recycleview adapter.
This is original CategoryAdapter.kt which is running well
package com.android.app.ui.category
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.RecyclerView
import coil.load
import com.google.android.gms.ads.AdListener
import com.google.android.gms.ads.AdRequest
import com.google.android.gms.ads.AdView
import com.android.app.R
import com.android.app.data.entities.Category
import com.android.app.data.type.CategoryType
import com.android.app.databinding.ItemCategoryBinding
import com.android.app.listener.PositionListener
class CategoryAdapter(private val list: List<Category>, private val listener: PositionListener) :
RecyclerView.Adapter<CategoryAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val binding =
ItemCategoryBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return ViewHolder(binding)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) = holder.bind(list[position])
override fun getItemCount(): Int = list.size
inner class ViewHolder(private val binding: ItemCategoryBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(category: Category) {
with(binding) {
ivCategory.load(
ContextCompat.getDrawable(
binding.root.context, when (category.id - 1) {
CategoryType.ART_CULTURE.ordinal -> R.drawable.ic_art_culture
CategoryType.GEOGRAPHY.ordinal -> R.drawable.ic_geography
CategoryType.MUSIC.ordinal -> R.drawable.ic_music
CategoryType.ECONOMY.ordinal -> R.drawable.ic_economy
CategoryType.HISTORY.ordinal -> R.drawable.ic_history
CategoryType.NATURE.ordinal -> R.drawable.ic_nature
CategoryType.FILM_TV.ordinal -> R.drawable.ic_film_tv
CategoryType.INFORMATICS.ordinal -> R.drawable.ic_informatics
CategoryType.FOOD_AND_DRINK.ordinal -> R.drawable.ic_food_and_drink
CategoryType.LANGUAGE.ordinal -> R.drawable.ic_language
CategoryType.SCIENCE.ordinal -> R.drawable.ic_science
CategoryType.GENERAL.ordinal -> R.drawable.ic_general
CategoryType.LITERATURE.ordinal -> R.drawable.ic_literature
CategoryType.SPORTS.ordinal -> R.drawable.ic_sports
else -> R.drawable.ic_politics
}
)
)
tvCategory.text = category.name
itemView.setOnClickListener {
listener.onItemClicked(category)
}
}
}
}
}
then I add this code to insert admob banner inside recycleview.adapter
var viewHolder: RecyclerView.ViewHolder? = null
val inflater = LayoutInflater.from(parent.context)
when (viewType) {
1 -> {
val v = inflater.inflate(R.layout.item_category, parent, false)
viewHolder = ViewHolder(binding = ItemCategoryBinding.bind(v))
}
2-> {
val v = inflater.inflate(R.layout.item_list_admob, parent, false)
viewHolder = AdmobViewHolder(v)
}
}
return viewHolder as ViewHolder
}
//show Admob Banner in list
class AdmobViewHolder(view: View) : RecyclerView.ViewHolder(view) {
var mAdView: AdView = view.findViewById<View>(R.id.adView) as AdView
init {
mAdView.visibility = View.GONE
mAdView.loadAd(AdRequest.Builder().build())
mAdView.adListener = object : AdListener() {
override fun onAdLoaded() {
super.onAdLoaded()
mAdView.visibility = View.VISIBLE
Log.i("LOG","Banner List Loaded")
}
override fun onAdFailedToLoad(errorCode : Int) {
Log.i("LOG","Banner List Failed to load")
}
}
}
}
This is the final result of the code that I modified to display the AdMob banner in recycleview.adapter
package com.android.app.ui.category
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.RecyclerView
import coil.load
import com.google.android.gms.ads.AdListener
import com.google.android.gms.ads.AdRequest
import com.google.android.gms.ads.AdView
import com.android.app.R
import com.android.app.data.entities.Category
import com.android.app.data.type.CategoryType
import com.android.app.databinding.ItemCategoryBinding
import com.android.app.listener.PositionListener
class CategoryAdapter(private val list: List<Category>, private val listener: PositionListener) :
RecyclerView.Adapter<CategoryAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
var viewHolder: RecyclerView.ViewHolder? = null
val inflater = LayoutInflater.from(parent.context)
when (viewType) {
1 -> {
val v = inflater.inflate(R.layout.item_category, parent, false)
viewHolder = ViewHolder(binding = ItemCategoryBinding.bind(v))
}
2-> {
val v = inflater.inflate(R.layout.item_list_admob, parent, false)
viewHolder = AdmobViewHolder(v)
}
}
return viewHolder as ViewHolder
// val binding =
// ItemCategoryBinding.inflate(LayoutInflater.from(parent.context), parent, false)
// return ViewHolder(binding)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) = holder.bind(list[position])
override fun getItemCount(): Int = list.size
//show Admob Banner in list
class AdmobViewHolder(view: View) : RecyclerView.ViewHolder(view) {
var mAdView: AdView = view.findViewById<View>(R.id.adView) as AdView
init {
mAdView.visibility = View.GONE
mAdView.loadAd(AdRequest.Builder().build())
mAdView.adListener = object : AdListener() {
override fun onAdLoaded() {
super.onAdLoaded()
mAdView.visibility = View.VISIBLE
Log.i("LOG","Banner List Loaded")
}
override fun onAdFailedToLoad(errorCode : Int) {
Log.i("LOG","Banner List Failed to load")
}
}
}
}
inner class ViewHolder(private val binding: ItemCategoryBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(category: Category) {
with(binding) {
ivCategory.load(
ContextCompat.getDrawable(
binding.root.context, when (category.id - 1) {
CategoryType.ART_CULTURE.ordinal -> R.drawable.ic_art_culture
CategoryType.GEOGRAPHY.ordinal -> R.drawable.ic_geography
CategoryType.MUSIC.ordinal -> R.drawable.ic_music
CategoryType.ECONOMY.ordinal -> R.drawable.ic_economy
CategoryType.HISTORY.ordinal -> R.drawable.ic_history
CategoryType.NATURE.ordinal -> R.drawable.ic_nature
CategoryType.FILM_TV.ordinal -> R.drawable.ic_film_tv
CategoryType.INFORMATICS.ordinal -> R.drawable.ic_informatics
CategoryType.FOOD_AND_DRINK.ordinal -> R.drawable.ic_food_and_drink
CategoryType.LANGUAGE.ordinal -> R.drawable.ic_language
CategoryType.SCIENCE.ordinal -> R.drawable.ic_science
CategoryType.GENERAL.ordinal -> R.drawable.ic_general
CategoryType.LITERATURE.ordinal -> R.drawable.ic_literature
CategoryType.SPORTS.ordinal -> R.drawable.ic_sports
else -> R.drawable.ic_politics
}
)
)
tvCategory.text = category.name
itemView.setOnClickListener {
listener.onItemClicked(category)
}
}
}
}
}
but I get the following error
2021-04-03 06:25:47.712 21532-21532/com.android.app E/RecyclerView: No adapter attached; skipping layout
2021-04-03 06:25:47.873 21532-21532/com.android.app E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.android.app, PID: 21532
java.lang.NullPointerException: null cannot be cast to non-null type com.android.app.ui.category.CategoryAdapter.ViewHolder
at com.android.app.ui.category.CategoryAdapter.onCreateViewHolder(CategoryAdapter.kt:35)
at com.android.app.ui.category.CategoryAdapter.onCreateViewHolder(CategoryAdapter.kt:19)
at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:7078)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6235)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:561)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1818)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1584)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at androidx.appcompat.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:530)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:810)
at android.view.View.layout(View.java:22160)
at android.view.ViewGroup.layout(ViewGroup.java:6402)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3330)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2826)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1901)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8066)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1041)
at android.view.Choreographer.doCallbacks(Choreographer.java:860)
at android.view.Choreographer.doFrame(Choreographer.java:785)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1026)
at android.os.Handler.handleCallback(Handler.java:914)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:225)
at android.app.ActivityThread.main(ActivityThread.java:7563)
I apologize for my ugly question, hope someone can help me. totally deadlocked for more than 1 week looking for the right way out to display the admob banner in recycleview.adapter.
Here you are trying to cast a nullable var to a non null which is not possible.
return viewHolder as ViewHolder
Provide a default ViewHolder instead.
return viewHolder?: DefaultViewHolder
Notice that your when statement may not assign a valid viewHolder and onCreateViewHolder badly needs one.