I can not speak english well, sorry.
how can I move GameScreen for Portrait mobile game like uploaded image?
I tried and success that using UGameViewportClient and SplitscreenInfo…
but It is not work on Android!!
so I must find another way now…
epic has fixed this bug but It is not true! It is still exists on 4.19.2!
(you can see the bug report → Unreal Engine Issues and Bug Tracker (UE-35204))