Create widget in pure C++

Development Programming & Scripting UI
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29

After digging into UUserWidget, found that setup the widget layout in NativeOnInitialized instead of NativeConstruct(). I Post the example code here and please noted that I put the code in an folder name UI

Public/UI/SCrosshair.h

#pragma once

#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "SCrosshair.generated.h"

class UImage;
class UCanvasPanel;
/**
 * 
 */
UCLASS()
class ACTIONROGUELIKE_API USCrosshair : public UUserWidget
{
	GENERATED_BODY()

protected:
	virtual void NativeOnInitialized() override;
};

Private/UI/SCrosshair.cpp

#include "UI/SCrosshair.h"
#include "Blueprint/WidgetBlueprintLibrary.h"
#include "Blueprint/WidgetTree.h"
#include "Components/CanvasPanel.h"
#include "Components/CanvasPanelSlot.h"
#include "Components/Image.h"

void USCrosshair::NativeOnInitialized()
{
	Super::NativeOnInitialized();
	
	auto MyCanvas = WidgetTree->ConstructWidget<UCanvasPanel>(UCanvasPanel::StaticClass());
	if(MyCanvas)
	{
		const FString tempIconPath = "Texture2D'/Game/UI/StyleBrush/FirstPersonCrosshair.FirstPersonCrosshair'";
		UTexture2D* tempTexture  =  LoadObject<UTexture2D>(this,*tempIconPath);
		auto CrossImage = WidgetTree->ConstructWidget<UImage>();
		CrossImage->SetBrush(UWidgetBlueprintLibrary::MakeBrushFromTexture(tempTexture));
		//CrossImage->SetBrushSize(FVector2D(16.0f,16.0f));
		MyCanvas->AddChild(CrossImage);
		const auto tempSlot =  Cast<UCanvasPanelSlot>(CrossImage->Slot);
		if(tempSlot)
		{
			tempSlot->SetAutoSize(true);
			tempSlot->SetOffsets(FMargin(0,0));
			tempSlot->SetAnchors(FAnchors(0.5f,0.5f));
		}
		WidgetTree->RootWidget = MyCanvas;
	}
}
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