Ad Size and Ad unit id must be set before loadAd is called

Question

I have this in my main xml file:

Answer 1

For anyone interested here is a Kotlin version.

And inside the code behind

//create a new AdView    
val adView = AdView(this)
adView.adSize = AdSize.SMART_BANNER
adView.adUnitId = "your adUnitID goes here or you can use a function"
adView.visibility = View.GONE

//add it to the layout
val layout = adContainer
layout.addView(adView)

//profit
MobileAds.initialize(this) {}
val adRequest = AdRequest.Builder().build()
adView.loadAd(adRequest)
adView.adListener = object : AdListener(){
    override fun onAdLoaded() {
        adView.visibility = View.VISIBLE
        super.onAdLoaded()
    }
}