Umg on Georgy's Tech Blog

Improve multi-line editable text box keyboard and gamepad navigations

Tue, 24 Dec 2024 00:00:00 +0000

Introduction

Still, as of UE 5.5, multi-line editable text boxes lack proper keyboard and gamepad navigation support. Let’s fix this without modifying the engine’s source code. I’ll experiment with a simple 2x2 grid of text boxes to demonstrate how we can implement smooth, unified navigation across both keyboard and gamepad input devices, which you can also recreate for testing purposes.

Current Limitations

Keyboard

Arrow keys only allow navigation within the content of a single text box, and there’s no way to navigate between text boxes themselves.

How to focus a Common UI button (UCommonButtonBase) in Unreal Engine

Tue, 27 Aug 2024 00:00:00 +0000

As of UE 5.4, the Common UI button (UCommonButtonBase) still doesn’t support direct focus settings. This is because UCommonButtonBase is derived from UUserWidget, which supports focusing, but doesn’t direct the focus to the underlying button itself automatically. However, you can still set the focus on the button by performing a “deep” focus on the Slate button. Here’s how you can achieve this:

/**
 * Sets the focus on the button
 * This function performs the "deep" focus on the Common UI button, which means that it will set the focus on the button itself
 * This is useful since UCommonButtonBase is derived from UUserWidget, which doesn't support focus when setting it directly
 */
UFUNCTION(BlueprintCallable, Category = "mod.io|UI|Button", DisplayName = "Set Button Focus (Common UI)")
void SetCommonUIButtonFocus()
{
#if UE_VERSION_OLDER_THAN(5, 3, 0)
	if (bIsFocusable)
#else
	if (IsFocusable())
#endif
	{
		if (TSharedPtr<SButton> SlateButton = GetSlateButton())
		{
			if (SlateButton->SupportsKeyboardFocus())
			{
				FSlateApplication::Get().SetKeyboardFocus(SlateButton, EFocusCause::Mouse);
				UE_LOG(LogTemp, Log, TEXT("Set focus on button '%s' (extended way)"), *GetName());
			}
			else
			{
				UE_LOG(LogTemp, Warning, TEXT("Trying to set focus on button '%s' but the button does not support keyboard focus"), *GetName());
			}
		}
		else
		{
			UE_LOG(LogTemp, Warning, TEXT("Trying to set focus on button '%s' but the slate button could not be found"), *GetName());
		}
	}
	else
	{
		UE_LOG(LogTemp, Warning, TEXT("Trying to set focus on button '%s' but the button is not focusable"), *GetName());
	}
}

/**
 * Gets the Slate button widget
 * The button is highly encapsulated and this function tries to scan the widget tree to find the button
 * @return The Slate button widget if found, nullptr otherwise
 */
TSharedPtr<SButton> GetSlateButton() const
{
	if (WidgetTree && WidgetTree->RootWidget)
	{
		if (UButton* InternalButton = Cast<UButton>(WidgetTree->RootWidget))
		{
			// UCommonButtonInternalBase::RebuildWidget() creates a SBox wrapper for the button
			if (TSharedPtr<SBox> BoxButtonWrapper =	StaticCastSharedPtr<SBox>(TSharedPtr<SWidget>(InternalButton->GetCachedWidget())))
			{
				if (BoxButtonWrapper->GetChildren() && BoxButtonWrapper->GetChildren()->Num() > 0)
				{
					if (TSharedPtr<SButton> InternalButtonSlate = StaticCastSharedPtr<SButton>(TSharedPtr<SWidget>(BoxButtonWrapper->GetChildren()->GetChildAt(0))))
					{
						return InternalButtonSlate;
					}
				}
			}
			// UButton::RebuildWidget() returns the button directly
			else if (TSharedPtr<SButton> InternalButtonSlate = StaticCastSharedPtr<SButton>(InternalButton->GetCachedWidget()))
			{
				return InternalButtonSlate;
			}
			else
			{
				UE_LOG(LogTemp, Error, TEXT("Could not find the Slate button widget for button '%s'"), *GetName());
			}
		}
	}
	return nullptr;
}

How to get the currently focused widget in Unreal Engine

Sat, 23 Mar 2024 00:00:00 +0000

In Unreal Engine, you can determine the currently focused widget in both Slate and UMG UI systems.

Slate

To get the currently focused Slate widget, you can use the following code snippet:

// Instead of 0, you can pass the user index if you have multiple users
TSharedPtr<SWidget> FocusedSlateWidget = FSlateApplication::Get().GetUserFocusedWidget(0);

UMG

Getting the currently focused UMG widget is a bit more involved, since there is no direct function to get it or the place where it is stored. However, you can iterate over all UMG widgets and compare their cached Slate widgets to the focused one. This approach is not recommended for performance-critical code, but it can be useful for debugging or testing purposes. Here is an example function that does this: