咱们在玩游戏的时候，通常会和界面进行各种各样的互动，而且会动都是在不同的界面上，所以需要在不同的界面上进行切换或者多个HUD重叠显示在一起。
首先创建两个HUD

2.重新定义一个PlayerController类

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/PlayerController.h"
#include "ChangeHUD/IChangeHUD.h"
#include "CameraPlayerController.generated.h"

/**
 *
 */
UCLASS()
class TRUEFPSPROJECT_API ACameraPlayerController 
	: public APlayerController
	, public IChangeHUD {
	GENERATED_BODY()

public:
	ACameraPlayerController();

	//编辑器内UMG资产的引用
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "AAA")
	TSubclassOf<class UUserWidget> mainHUDAsset;

	//创建后用于空间变量
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "AAA")
	UUserWidget* mainHUDMenu;
	
	//编辑器内UMG资产的引用
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "AAA")
	TSubclassOf<class UUserWidget> subHUDAsset;

	//创建后用于空间变量
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "AAA")
	UUserWidget* subHUDMenu;

	virtual void BeginPlay();

	virtual void changeHUD()override;
private:
	int32 HUDChoose = 0;//切换不同的HUD界面
	UUserWidget* _currentHUD = nullptr;
};

// Fill out your copyright notice in the Description page of Project Settings.


#include "CameraPlayerController.h"
#include "Blueprint/UserWidget.h"
#include "ChangeHUD/ChangeHUDManager.h"

ACameraPlayerController::ACameraPlayerController() {
	ChangeHUDMgr()->changeHUDInterface = this;
}

void ACameraPlayerController::BeginPlay() {
	Super::BeginPlay();
	if (mainHUDAsset) {
		mainHUDMenu = CreateWidget<UUserWidget>(this, mainHUDAsset);
	}

	if (subHUDAsset) {
		subHUDMenu = CreateWidget<UUserWidget>(this, subHUDAsset);
	}
}

void ACameraPlayerController::changeHUD() {
	if (_currentHUD) {
		_currentHUD->RemoveFromViewport();
	}
	HUDChoose += 1;
	if (HUDChoose%3 == 0){
		_currentHUD = mainHUDMenu;
		_currentHUD->AddToViewport();

	} else if(HUDChoose % 3 == 1) {
		_currentHUD = subHUDMenu;
		_currentHUD->AddToViewport();

	}else{
		mainHUDMenu->AddToViewport();
		subHUDMenu->AddToViewport();
	}

}

定义一个接口类和接口管理类

#pragma once
class IChangeHUD {

public:
	virtual void changeHUD() = 0;
};

#pragma once

#define ChangeHUDMgr() (ChangeHUDManager::getInstance())

class ChangeHUDManager {
private:
	ChangeHUDManager();
	static ChangeHUDManager* _instance;
public:
	static ChangeHUDManager* getInstance();

	class IChangeHUD* changeHUDInterface;
};

#include "ChangeHUDManager.h"
#include "IChangeHUD.h"

ChangeHUDManager* ChangeHUDManager::_instance = new ChangeHUDManager;

ChangeHUDManager::ChangeHUDManager() {

}

ChangeHUDManager* ChangeHUDManager::getInstance() {
	return _instance;
}

在角色类中通过按键H来调用：

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "SpawnActor.generated.h"

UCLASS()
class TRUEFPSPROJECT_API ASpawnActor : public AActor {
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	ASpawnActor();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:
	// Called every frame
	virtual void Tick(float DeltaTime) override;

public:
	UPROPERTY(EditAnywhere, Category = "AAA")
	TSubclassOf<class AFloatingActor> subFloatingActor;

	float baseTime = 0.0;
};

// Fill out your copyright notice in the Description page of Project Settings.


#include "SpawnActor.h"
#include "FloatingActor.h"

// Sets default values
ASpawnActor::ASpawnActor() {
	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void ASpawnActor::BeginPlay() {
	Super::BeginPlay();

}

// Called every frame
void ASpawnActor::Tick(float DeltaTime) {
	Super::Tick(DeltaTime);

	if ((baseTime += DeltaTime) <= 3.0){
		return;
	}

	baseTime = 0.0;

	UWorld* world = GetWorld();
	if (world){
		FVector spawnLocation = GetActorLocation();
		FRotator spwanRotation = GetActorRotation();

		FActorSpawnParameters spawnParam;
		spawnParam.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AdjustIfPossibleButDontSpawnIfColliding;

		world->SpawnActor<AFloatingActor>(subFloatingActor, spawnLocation, spwanRotation, spawnParam);
	}
}

点击【运行】

aaa