B4A Library FirebaseAdMob2 - Google Mobile Ads SDK v20+

CreateResourceFromFile(Macro, FirebaseAnalytics.GooglePlayBase)
CreateResourceFromFile (Macro, FirebaseAdMob.FirebaseAds)
AddReplacement($ADMOB_APP_ID$, ca-app-pub-12673333333~67613333333)

Dim m As MobileAds
Wait For (m.Initialize) MobileAds_Ready
m.SetConfiguration(m.CreateRequestConfigurationBuilder(Array("77A04EE40B2AFED2AFC67701365187EC"))) 'optional. Array with test device ids. See unfiltered logs to find id.

Sub Activity_Create(FirstTime As Boolean)
   Dim AdaptiveSize As Map = GetAdaptiveAdSize
   'Add Private BannerAd As AdView in Globals sub
   BannerAd.Initialize2("BannerAd", "ca-app-pub-3940256099942544/6300978111",AdaptiveSize.Get("native"))
   Activity.AddView(BannerAd, 0, 0,  AdaptiveSize.Get("width"), AdaptiveSize.Get("height"))
   BannerAd.LoadAd
End Sub

Sub GetAdaptiveAdSize As Map
    Dim ctxt As JavaObject
    ctxt.InitializeContext
    Dim AdSize As JavaObject
    Dim width As Int = 100%x / GetDeviceLayoutValues.Scale
    Dim Native As JavaObject = AdSize.InitializeStatic("com.google.android.gms.ads.AdSize").RunMethod("getCurrentOrientationAnchoredAdaptiveBannerAdSize", Array(ctxt, width))
    Return CreateMap("native": Native, "width": Native.RunMethod("getWidthInPixels", Array(ctxt)), _
        "height": Native.RunMethod("getHeightInPixels", Array(ctxt)))
End Sub

Sub Ad_ReceiveAd
    Log("Adview received")
End Sub

Sub Ad_FailedToReceiveAd (ErrorCode As String)
    Log("Failed: " & ErrorCode)
End Sub

Sub Ad_AdClosed
    Log("Closed")
End Sub

Sub Ad_AdOpened
    Log("Opened")
End Sub

'Add Private iAd As InterstitialAd in Globals sub
iad.Initialize("iad", "ca-app-pub-3940256099942544/1033173712")
iad.LoadAd


Sub iAd_ReceiveAd
    Log("IAd received. Now wait for the right moment to show the ad.")
    If ad.Ready Then
       ad.Show 'bad example. You should instead wait for the correct time and show it when it makes sense.
    End If
End Sub

Sub iAd_FailedToReceiveAd (ErrorCode As String)
    Log("Failed: " & ErrorCode)
End Sub

Sub iAd_AdClosed
    Log("Closed")
End Sub

Sub iAd_AdOpened
    Log("Opened")
End Sub