Root casue for NoSuchElementException: Collection is empty - kotlin

Question

I am facing Crash in Firebase Crashlytics on bind method but unable to find the root cause. I have added a Null check but still, the issue not fixed.
Firebase Crash Report
Fatal Exception: java.util.NoSuchElementException: Collection is empty.
at kotlin.collections.CollectionsKt___CollectionsKt.first(_Collections.kt:184)
at com.transferhome.contacts.ContactsAdapter.bind(ContactsAdapter.kt:25)
at com.transferhome.contacts.ContactsBaseAdapter.onBindViewHolder(ContactsBaseAdapter.kt:38)
at com.transferhome.contacts.ContactsBaseAdapter.onBindViewHolder(ContactsBaseAdapter.kt:19)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6781)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6823)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5752)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6019)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1557)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3924)
at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java:3336)
at android.view.View.measure(View.java:22216)
at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
at android.view.View.measure(View.java:22216)
at androidx.viewpager.widget.ViewPager.onMeasure(ViewPager.java:1638)
at android.view.View.measure(View.java:22216)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1676)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:733)
at com.google.android.material.appbar.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:95)
at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1556)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:803)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1539)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:823)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:702)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1539)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:823)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:702)
at android.view.View.measure(View.java:22216)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6671)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:831)
at android.view.View.measure(View.java:22216)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2589)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1631)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1885)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1515)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7266)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:981)
at android.view.Choreographer.doCallbacks(Choreographer.java:790)
at android.view.Choreographer.doFrame(Choreographer.java:721)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:967)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7529)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)
ContactsAdapter.kt
class ContactsAdapter ( private val onItemSelect: (contact: Contact) -> Unit )
: ContactsBaseAdapter<ItemContactFavListBinding>() {
var contactFavSignal = MutableLiveData<Contact>().apply { }
override fun bind(contact: Contact, holder: ContactVH<ItemContactFavListBinding>) {
val binding = holder.binding
binding.contactName.text = contact.name
binding.contactNumber.text = contact.numbers.first().phone
binding.imgContactHeart.setOnClickListener(View.OnClickListener {
val backgroundImageName = (binding.imgContactHeart.getTag()).toString()
if(backgroundImageName.equals("2")) {
binding.imgContactHeart.setImageResource(R.drawable.heart_selected_yellow)
EventBus.getDefault().post(CustomEvent(contact,true));
binding.imgContactHeart.setTag("1")
binding.imgContactHeart.setImageResource(R.drawable.heart_selected_yellow)
}else if(backgroundImageName.equals("1")) {
binding.imgContactHeart.setImageResource(R.drawable.heart_selected_yellow)
EventBus.getDefault().post(CustomEvent(contact,false));
binding.imgContactHeart.setTag("2")
binding.imgContactHeart.setImageResource(R.drawable.heart)
}
})
var num = contact.numbers.first().phone
if(num.contains(" "))
num = num.replace(" ","")
if(num.startsWith("0"))
num = num.removePrefix("0")
if(num.startsWith("+"))
num = num.removePrefix("+")
var isFav:Boolean=false
for (x in 0..FavoritesFragment.listFavNumbers.size-1)
{
var num2 = FavoritesFragment.listFavNumbers[x]
if(num2.endsWith(num))
isFav=true
}
if(isFav)
{
binding.imgContactHeart.setTag("1")
binding.imgContactHeart.setImageResource(R.drawable.heart_selected_yellow)
}
else
{
binding.imgContactHeart.setTag("2")
binding.imgContactHeart.setImageResource(R.drawable.heart)
}
showContactProfileImage(contact, binding.contactImage)
holder.binding.root.setOnClickListener {
onItemSelect.invoke(contact)
}
}
override fun provideBinding(inflater: LayoutInflater, parent: ViewGroup): ItemContactFavListBinding {
return ItemContactFavListBinding.inflate(inflater, parent, false)
}
}
ContactBaseAdater.kt
abstract class ContactsBaseAdapter<T : ViewDataBinding> :
PagedListAdapter<Contact, ContactsBaseAdapter.ContactVH<T>>(object : DiffUtil.ItemCallback<Contact>() {
override fun areItemsTheSame(oldItem: Contact, newItem: Contact): Boolean {
return oldItem.name == newItem.name || oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: Contact, newItem: Contact): Boolean {
return oldItem.name == newItem.name
}
} ) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ContactVH<T> {
return ContactVH(provideBinding(LayoutInflater.from(parent.context), parent))
}
override fun onBindViewHolder(holder: ContactVH<T>, position: Int) {
val contact = getItem(position)
if (contact != null) {
bind(contact, holder)
}
}
abstract fun bind(contact: Contact, holder: ContactVH<T>)
abstract fun provideBinding(inflater: LayoutInflater, parent: ViewGroup): T
class ContactVH<T : ViewDataBinding>(val binding: T) : RecyclerView.ViewHolder(binding.root)
fun showContactProfileImage(contact: Contact, imageHolder: ImageView?) {
UiUtils.showContactProfileImage(contact, imageHolder)
}
}
item_contact_fav_list.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<RelativeLayout android:layout_width="match_parent"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_height="wrap_content"
android:orientation="horizontal"
tools:ignore="UseCompoundDrawables">
<ImageView
android:id="#+id/contact_image"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:layout_alignParentLeft="true"
android:contentDescription="#null"/>
<LinearLayout android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="vertical"
android:weightSum="2"
android:layout_toLeftOf="#+id/img_contact_heart"
android:layout_toRightOf="#+id/contact_image"
android:layout_marginLeft="5dp">
<TextView
android:id="#+id/contact_name"
android:textSize="16sp"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_gravity="center"
android:layout_weight="1"
android:singleLine="true"
android:ellipsize="middle"
android:focusable="false"
android:textColor="#color/colorBlack"
android:layout_marginTop="3dp"
tools:text="Contact Name"/>
<TextView
android:id="#+id/contact_number"
android:textSize="15sp"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_gravity="center"
android:layout_weight="1"
android:singleLine="true"
android:textColor="#android:color/darker_gray"
tools:text="Contact Name"
android:layout_marginLeft="5dp"
/>
</LinearLayout>
<ImageView
android:layout_alignParentRight="true"
android:id="#+id/img_contact_heart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/heart"
android:layout_centerVertical="true"
/>
</RelativeLayout>
</layout>

Answer 1

Let's take a look at the stacktrace:
Fatal Exception: java.util.NoSuchElementException: Collection is empty.
at kotlin.collections.CollectionsKt___CollectionsKt.first(_Collections.kt:184)
at com.transferhome.contacts.ContactsAdapter.bind(ContactsAdapter.kt:25)
Most probably, the line referred to is this one:
binding.contactNumber.text = contact.numbers.first().phone
the call to first() in particular. If contact.numbers is empty, first() will throw a NoSuchElementException. Your code does not handle this case.
The easiest solution would be to set the text to null if there are no numbers:
binding.contactNumber.text = contact.numbers.firstOrNull()?.phone
Why would you add a nullcheck if the exception was not a NullPointerException?