Error: Java.lang.illegalargumentexception: Parameter Specified As Non-null Is Null Firebase Transaction Kotlin

I am trying to increment an integer in Firebase database but, the app crashes. abstract class BrowserActivity : ThemableBrowserActivity(),OnClickListener { private var mAu

Solution 1:

With reference to this post, I am passing databaseError as null to onComplete. By default all variables in kotlin are non null. So, if I want to pass a null parameter, I have to add a ? to the parameter, which in my case should be DatabaseError?. So the onComplete function should look like:

override fun onComplete(databaseError: DatabaseError?, b: Boolean, dataSnapshot: DataSnapshot) {}