Animating a Slate widget

Here’s a simple example of how to create an animated Slate widget, which slides in from the left when constructed, and slides out to the right when SetAnimateOut is called.

//.h
DECLARE_MULTICAST_DELEGATE(FUFLoadingScreen_Event);
 
class UNFURNISHED_API SUFLoadingScreen : public SCompoundWidget
{
public:
	SLATE_BEGIN_ARGS(SUFLoadingScreen) {}
	SLATE_END_ARGS()
 
	void Construct(const FArguments& InArgs);
	
	void SetAnimateOut(const bool bOut);
 
 
	FUFLoadingScreen_Event OnAnimationFinished;
protected:
	FCurveSequence Animation;
	FCurveHandle CurveHandle;
 
	float PositionOffset = 0;
	bool bPositionInitialized = false;
	bool bWasAnimating = false;
 
	bool bAnimateOut = false;
 
	virtual void Tick(const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime) override;
};

//.cpp
void SUFLoadingScreen::Construct(const FArguments& InArgs)
{
	FSlateFontInfo Font = FAppStyle::Get().GetFontStyle("Regular");
	Font.Size = 40;
 
	Animation = FCurveSequence(0, 0.5f);
	CurveHandle = Animation.AddCurve(0.f, 0.5f, ECurveEaseFunction::QuadInOut);
	
	ChildSlot
	[
		SNew(SBorder)
		.BorderImage(FAppStyle::GetBrush("WhiteBrush"))
		.BorderBackgroundColor(FLinearColor::Gray)
		.HAlign(HAlign_Center)
		.VAlign(VAlign_Center)
		[
			SNew(STextBlock)
			.ColorAndOpacity(FLinearColor::Black)
			.Font(Font)
			.Text(INVTEXT("Loading"))
		]
		.RenderTransform_Lambda([this]()
		{
			return FSlateRenderTransform(FVector2D(PositionOffset, 0));
		})
		.Visibility_Lambda([this]()
		{
			//This avoids the widget from flashing on screen before the render transform offset is set
			return bPositionInitialized ? EVisibility::Visible : EVisibility::Hidden;
		})
	];
 
	bWasAnimating = true;
	Animation.Play(SharedThis(this), false);
}
 
void SUFLoadingScreen::SetAnimateOut(const bool bOut)
{
	bAnimateOut = bOut;
	bWasAnimating = true;
	Animation.Play(AsShared());
}
 
void SUFLoadingScreen::Tick(const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime)
{
	SCompoundWidget::Tick(AllottedGeometry, InCurrentTime, InDeltaTime);
	if(bAnimateOut)
	{
		PositionOffset = CurveHandle.GetLerp() * AllottedGeometry.Size.X;
	}
	else
	{
		PositionOffset = -1 * ((1 - CurveHandle.GetLerp()) * AllottedGeometry.Size.X);
	}
	
	bPositionInitialized = true;
 
	if(bWasAnimating && !Animation.IsPlaying())
	{
		bWasAnimating = false;
		OnAnimationFinished.Broadcast();
	}
}