This solution I have tested. and Its working. only trick is, you have to set
callout.style=Callout.Style(context,resourceId)
, whenever your are calling
callout.show()
val calloutContent = layoutInflater.inflate(R.layout.callout_map, root, false)
val mCallout = mapView.callout
mCallout.style = Callout.Style(this, R.xml.callout_style)
mCallout.location = point
mCallout.content = calloutContent
mCallout.show()