Can I declare a variable to hold a Widget BP Reference?

Development Programming & Scripting C++
1

What I want to do is to have a variable to a reference of a Widget BP I have in my content browser. Let’s say I went in my browser and made a widget named “MyItemWidget”.
Is it possible to declare a “AMyItemWidget *ItemWidgetRef;” inside my character? Or would it just be easier to just create a widget subclass I can use to access its members directly?

2

There is a generic UWidgetBlueprint class, but I’m not sure how useful that would be at run-time (if you can access it at runtime), it looks like the blueprint gets compiled down to a UUserWidget. Generally, widgets simply read or write data to some other object (i.e. your player), so I’m not sure how you would access any widget specific members you create via blueprint.

3

Yeah, I guess it just isn’t possible. I found a way around by setting up a TSubClassOf<UUserWidget> and a UUserWidget pointer and then in the blueprint defining which widget to use for the TSubClassOf.

4

I’m not sure to what extent you’re looking for. But I created a HUD inside UMG, but I load it through C++.

Controller Class Header



UPROPERTY() //The class
	TSubclassOf<UUserWidget> CharacterSelectWidgetClass;
	UPROPERTY() //The instance
	class UUserWidget* CharacterSelectWidget;

Controller Class .cpp



ABLTPlayerController::ABLTPlayerController(const FObjectInitializer& ObjectInitializer)
:Super(ObjectInitializer)
{
	static ConstructorHelpers::FClassFinder<UUserWidget> BlueprintClass(TEXT("/Game/UI/Menus/BP_UI_Menus_CharacterSelect"));
	
	if (BlueprintClass.Class)
		CharacterSelectWidgetClass = BlueprintClass.Class;


}

void ABLTPlayerController::OpenCharacterMenu()
{
	if (!CharacterSelectWidgetClass) //Missing widget class, can't continue
		return;

	if (!CharacterSelectWidget) //No widget, let's create it
		CharacterSelectWidget = CreateWidget<UUserWidget>(this, CharacterSelectWidgetClass);

	if (!CharacterSelectWidget) //Failed to create widget
		return;

	CharacterSelectWidget->AddToViewport();
	bShowMouseCursor = true;
	
}
5

Thanks for the example, but the problem here is that that way I cannot access the local variables created within that blueprint. Like, if that “BP_UI_Menus_CharacterSelect” has a int variable, you can’t access it from C++ because it’s not a subclass declared within code, thus, you can’t access its members.

1 Like
6

You could define a new base class for your widgets by extending UUserWidget in C++ and reparent your Widget Blueprint. Your base class could have all those members you want to access from C++. Though I don’t recommend that design, where possible a good UI design should poll or listen for changes from the game. It’s generally a bad idea to be directly pushing changes to the UI from game code.

7

Well, that sorta what I’m doing. I’m using an extended Widget class for my HUD with some variables in it that I update from the code (What I’m updating are values from my character which are declared in code, so I don’t think that’s a problem) and then I use those values on the widget I want them to do something.

8

I could still be off basis here on what you’re trying to achieve. But it sounds like you might have your logic a little more complex than it needs to be. If you’re pulling information from your character, then trying to update a custom widget variable, then trying to pull that information into Blueprint to use with your HUD, then it seems like you’re adding a lot more overhead than needed.

Again, could be off basis. But I have my HUD that I made through UMG. I don’t have any custom widgets. I simply use the method above, and then inside the Blueprint graph of the UMG I’m extensively using the “Get Player Character” node, and I call custom C++ declared functions that are exposed to blueprint likes GetPlayerHealth() and GetWeapon()->GetAmmo() etc, etc to update the blueprint.

So at this point, the Blueprint is always simply listening for updates, rather than having its own version of all the variables I need to check.