UE5 C++ 动态多播

一.声明，多播的几个要点

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DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams (FXGDynamicmulticastThree,FString ,InName,int32 ,InHealth,int32 ,InMana);

1.如果想要蓝图绑定，那么委托变量声明需要加 BlueprintAssignable 这个宏

原来变量里面也有BlurprintCallable 属性，但这个无法实现常规的蓝图事件事件绑定，可能要用Call绑定

2.多播绑定的函数必须加入反射系统（有UFUNCTION宏），不然找不到，也就失去了多播的意义。

3.多播的值，不能作为反射系统函数里的传参值。在C++里自由传值。

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	//UFUNCTION(BlueprintCallable)
	void InitMutiEvent(FXGDynamicmulticastThree tmpMutiEvent);

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void AWXDynimicMultiCastActor::InitMutiEvent(FXGDynamicmulticastThree tmpMutiEvent)
{
	MutiEvent = tmpMutiEvent;
}

二.绑定

1.C++ 绑定 AddDynamic

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AddDynamic(this, &AHMSDataCenter::HistoryPathOnClick);

这里在Begin Play里就绑定，参数要相同。在

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void AWXDynimicMultiCastActor::BeginPlay()
{
	Super::BeginPlay();
	MutiEvent.AddDynamic(this,&AWXDynimicMultiCastActor::WorkMutiEvent);
}

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void AWXDynimicMultiCastActor::WorkMutiEvent(FString InName, int32 InHealth, int32 InMana)
{
	UE_LOG(LogTemp,Warning,TEXT("%s, %d, %d"),*InName,InHealth,InMana);
}

解绑使用如下函数

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	MutiEvent.RemoveDynamic(this, &AWXDynimicMultiCastActor::WorkMutiEvent);

2.蓝图绑定

也是在Begin Play里绑定，在EndPlay里解绑

再来个在关卡蓝图里绑定，这里执行玩一次就解绑了

三. 执行

动态多播统一用 Broadcast并且传入和声明时的参数相同即可。

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void AWXDynimicMultiCastActor::CallMutiEvent(FString InName, int32 InHealth, int32 InMana)
{
	MutiEvent.Broadcast(InName,InHealth,InMana);
}

四.

这里绑定了三个响应函数，一个C++，两个蓝图。其中一个在执行一次后就解绑。这就是动态多播魅力。可以想帮多少个，就绑定多少个。还可以不像例子里在自己的类里绑定多个，还可以去其他类里绑定，AddDynamic第一个参数就填入其他类的实例。其实感觉最好用的就是把委托事件在单例里声明，这样任何类都可以拿来声明并绑定。完整代码如下

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

#pragma once

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

//DECLARE_DYNAMIC_MULTICAST_
//DECLARE_DYNAMIC_DELEGATE_TwoParams
//动态多播
DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams (FXGDynamicmulticastThree,FString ,InName,int32 ,InHealth,int32 ,InMana);

UCLASS()
class THIRDLEARN_API AWXDynimicMultiCastActor : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AWXDynimicMultiCastActor();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	//UFUNCTION(BlueprintCallable)
	void InitMutiEvent(FXGDynamicmulticastThree tmpMutiEvent);
	UFUNCTION(BlueprintCallable)
	void CallMutiEvent(FString InName, int32 InHealth, int32 InMana);
	UFUNCTION(BlueprintCallable)
	void WorkMutiEvent(FString InName, int32 InHealth, int32 InMana);
	UFUNCTION(BlueprintCallable)
	void RealseMutiEvent();
public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;
	UPROPERTY(BlueprintAssignable)
	FXGDynamicmulticastThree MutiEvent;

};

cpp 复制代码

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


#include "WXDynimicMultiCastActor.h"

// Sets default values
AWXDynimicMultiCastActor::AWXDynimicMultiCastActor()
{
 	// 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 AWXDynimicMultiCastActor::BeginPlay()
{
	Super::BeginPlay();
	MutiEvent.AddDynamic(this,&AWXDynimicMultiCastActor::WorkMutiEvent);
	//MutiEvent.RemoveDynamic(this, &AWXDynimicMultiCastActor::WorkMutiEvent);
}

void AWXDynimicMultiCastActor::InitMutiEvent(FXGDynamicmulticastThree tmpMutiEvent)
{
	MutiEvent = tmpMutiEvent;
}

void AWXDynimicMultiCastActor::CallMutiEvent(FString InName, int32 InHealth, int32 InMana)
{
	MutiEvent.Broadcast(InName,InHealth,InMana);
}

void AWXDynimicMultiCastActor::WorkMutiEvent(FString InName, int32 InHealth, int32 InMana)
{
	UE_LOG(LogTemp,Warning,TEXT("%s, %d, %d"),*InName,InHealth,InMana);
}


void AWXDynimicMultiCastActor::RealseMutiEvent()
{
	MutiEvent.RemoveDynamic(this, &AWXDynimicMultiCastActor::WorkMutiEvent);
}

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

}