纯C++事件

一、创建多播委托类型及对象

1、AUECpp_Sender.h

	//声明一个参数多播委托的类型，一定要F开头
	DECLARE_MULTICAST_DELEGATE_OneParam(FUECpp_Broadcast, int);
	//创建对象
	FUECpp_Broadcast UECpp_Broadcast;

2、AUECpp_Sender.cpp

	//发送广播
	UECpp_Broadcast.Broadcast(FMath::RandRange(0, 100));

二、订阅及取消订阅

1、AUECpp_Receiver.h

protected:
	virtual void BeginPlay() override;

public:
	void OnReceived(int Param);	

2、AUECpp_Receiver.cpp

#include "UECpp_Sender.h"
#include "Kismet/GameplayStatics.h"
#include "Engine/Engine.h"
#include "TimerManager.h"

void AUECpp_Receiver::BeginPlay()
{
	Super::BeginPlay();
	//订阅
	AUECpp_Sender* PlayerPawn = Cast<AUECpp_Sender>(UGameplayStatics::GetPlayerPawn(this, 0));
	FDelegateHandle DelegateHandle = PlayerPawn->UECpp_Broadcast.AddUObject(this, &AUECpp_Receiver::OnReceived);

	//计时器
	FTimerHandle TimerHandle;
	auto Lambda = [PlayerPawn, DelegateHandle, this]()
		{
			//取消订阅
			PlayerPawn->UECpp_Broadcast.Remove(DelegateHandle);
			//取消指定类里所有订阅
			PlayerPawn->UECpp_Broadcast.RemoveAll(this->GetPrivateStaticClass());
			//取消所有订阅
			PlayerPawn->UECpp_Broadcast.Clear();
		};
	GetWorld()->GetTimerManager().SetTimer(TimerHandle, FTimerDelegate::CreateLambda(Lambda), 5.0f, false);
}

void AUECpp_Receiver::OnReceived(int Param)
{
	GEngine->AddOnScreenDebugMessage(INDEX_NONE, 10.0f, FColor::Green, FString::Printf(TEXT("%i"), Param));
}