You cannot do that, the error message is pretty explicit, and also, this does not make any sense.
First, you cannot do that, like the error is telling you : Can only inherit from non-UObjects
The APlayerController class inherits from UObject, like you can see here:
Also, why would your PlayerController also be a UserWidget? This does not make any sense, one is used to control the player in game, the other is used to do interface. It would be like an Apple trying to inherit from a Car!
I would recomment you go and see some tutorial on how to implement a UUserWidget. And here, I found a post for you that does just that :
I’m trying to code a simple main menu. I followed the tutorial you gave me, but there was no indication on when to initiate the tutorial. I have a UUserWidget reparented to a simple UMG. However, I couldn’t get the widget to appear on screen. So, I found an example and on his example, he put the drawing on his player controller and reparented his UMG to his player controller to draw his main menu. I am having difficulties reparenting my UMG because unreal needs UUserWidget to be implemented. I’m looking for a work around. I understand what the error is telling me and I can’t do this syntax, but is there another syntax that will do the same thing.
Unfortunately, I cannot help you further. If what you want to do is a simple interface, there is plenty tutorial out there to do just that. Here is the documentation to do that :
I believe that if you take the time to read this, you should be able to start working on a simple interface in UE4.