Android Kotlin：null 不能转换为非 null 类型com.android.app.ui.category.CategoryAdapter.ViewHolder 想在 recycleviewholder 中插入 admob
Android Kotlin : null cannot be cast to non-null type com.android.app.ui.category.CategoryAdapter.ViewHolder want to insert admob in recycleviewholder
由于对 Kotlin 编程语言的了解有限，我尝试正常编辑以前 运行ning 的代码。我的目标是在已经 运行 正常的 recycleview 数据之间添加 admob 横幅。我已经尝试了 1 周或更长时间，但没有显着效果，请帮助使 Admob 横幅功能可以 运行 在 recycleview 适配器上正常使用。
这是原创CategoryAdapter.kt这是运行宁井
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)
}
}
}
}
}
然后我添加此代码以在 recycleview.adapter
中插入 admob 横幅
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")
}
}
}
}
这是我在 recycleview.adapter
中修改以显示 AdMob 横幅的代码的最终结果
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)
}
}
}
}
}
但是我得到以下错误
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)
我为我的丑陋问题道歉，希望有人能帮助我。完全陷入僵局超过 1 周，寻找在 recycleview.adapter.
中显示 admob 横幅的正确出路
您在此处尝试将可空变量转换为非空变量，这是不可能的。
return viewHolder as ViewHolder
改为提供默认的 ViewHolder。
return viewHolder?: DefaultViewHolder
请注意，您的 when 语句可能无法分配有效的 viewHolder，onCreateViewHolder 急需一个。
由于对 Kotlin 编程语言的了解有限，我尝试正常编辑以前 运行ning 的代码。我的目标是在已经 运行 正常的 recycleview 数据之间添加 admob 横幅。我已经尝试了 1 周或更长时间，但没有显着效果，请帮助使 Admob 横幅功能可以 运行 在 recycleview 适配器上正常使用。
这是原创CategoryAdapter.kt这是运行宁井
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)
}
}
}
}
}
然后我添加此代码以在 recycleview.adapter
中插入 admob 横幅 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")
}
}
}
}
这是我在 recycleview.adapter
中修改以显示 AdMob 横幅的代码的最终结果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)
}
}
}
}
}
但是我得到以下错误
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)
我为我的丑陋问题道歉，希望有人能帮助我。完全陷入僵局超过 1 周，寻找在 recycleview.adapter.
中显示 admob 横幅的正确出路您在此处尝试将可空变量转换为非空变量，这是不可能的。
return viewHolder as ViewHolder
改为提供默认的 ViewHolder。
return viewHolder?: DefaultViewHolder
请注意，您的 when 语句可能无法分配有效的 viewHolder，onCreateViewHolder 急需一个。