MyObject.h

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

#pragma once

#include "CoreMinimal.h"
#include "UObject/NoExportTypes.h"
#include "MyObject.generated.h"

/**
 * 
 */
UCLASS(Blueprintable) //可生成蓝图的
class FIRSTDEMO_API UMyObject : public UObject
{
	GENERATED_BODY()

public:

	//构造函数
	UMyObject();

	//成员变量
	UPROPERTY(BlueprintReadWrite,Category="My Viriables")
	float test;
	//成员函数
	UFUNCTION(BlueprintCallable,Category="My Functions")
	void Myfunction();

};

MyObject.cpp

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


#include "MyObject.h"
#include "Logging/LogMacros.h"
#include "Engine/Engine.h"


UMyObject::UMyObject() //构造函数实现，在构造函数中初始化成员变量的值
{
	test = 0.0f;
}

void UMyObject::Myfunction()
{
	//日志打印信息
	//Log 不能大写，大写的话是另一个枚举参数
	UE_LOG(LogTemp, Log, TEXT("Hello World !"));
	UE_LOG(LogTemp, Warning, TEXT("Hello World !"));
	UE_LOG(LogTemp, Error, TEXT("Hello World !"));
	//在屏幕上打印输出信息
	GEngine->AddOnScreenDebugMessage(-1, 10.f, FColor::Black, TEXT("Hello World !"));
}