UE5 C++（十二）— 委托（代理）、多播委托
这里写目录标题
- 介绍
-
- 定义
- 声明委托
- 绑定委托
- 执行委托
- 单播委托
- 多播委托
- 动态多播代理
介绍
这个官网上有很详细介绍，这里介绍几个点
定义
委托 是一种泛型但类型安全的方式，可在C++对象上调用成员函数。可使用委托动态绑定到任意对象的成员函数，之后在该对象上调用函数，即使调用程序不知对象类型也可进行操作。复制委托对象很安全。你也可以利用值传递委托，但这样操作需要在堆上分配内存，因此通常并不推荐。请尽量通过引用传递委托。
声明委托
UDELEGATE(BlueprintAuthorityOnly)
DECLARE_DYNAMIC_MULTICAST_DELEGATE_FourParams(FInstigatedAnyDamageSignature, float, Damage, const UDamageType*, DamageType, AActor*, DamagedActor, AActor*, DamageCauser);
绑定委托
MyDelegate.BindRaw( &MyFunction, true, 20 );
执行委托
WriteToLogDelegate.Execute(TEXT("Delegates are great!"));
单播委托
单播委托 只能绑定一个函数
创建一个C++类 MyDelegateActor
MyDelegateActor.h
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "MyDelegateActor.generated.h"
DECLARE_DELEGATE(NoParamDelegate);//声明一个无参委托
DECLARE_DELEGATE_OneParam(OneParamDelegate, int32);//声明一个有一个int32参数的委托
DECLARE_DELEGATE_TwoParams(TwoParamsDelegate, int32, FString);//声明一个有一个int32参数和一个FString参数的委托
DECLARE_DELEGATE_RetVal(int32, RetValDelegate);//声明一个有返回值的委托
UCLASS()
class DEMO_API AMyDelegateActor : public AActor
{
GENERATED_BODY()
public:
// Sets default values for this actor's properties
AMyDelegateActor();
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
NoParamDelegate NoParamDelegate;//声明一个无参委托
OneParamDelegate OneParamDelegate;//声明一个有一个int32参数的委托
TwoParamsDelegate TwoParamsDelegate;//声明一个有一个int32参数和一个FString参数的委托
RetValDelegate RetValDelegate;//声明一个有返回值的委托
void NoParamDelegateFunc();//无参委托函数
void OneParamDelegateFunc(int32 Param);//有一个int32参数的委托函数
void TwoParamsDelegateFunc(int32 Param1, FString Param2);//有一个int32参数和一个FString参数的委托函数
int32 RetValDelegateFunc();//有返回值的委托函数
};
MyDelegateActor.cpp
#include "MyDelegateActor.h"
// Sets default values
AMyDelegateActor::AMyDelegateActor()
{
// 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;
NoParamDelegate.BindUObject(this, &AMyDelegateActor::NoParamDelegateFunc); // 绑定无参委托函数
OneParamDelegate.BindUObject(this, &AMyDelegateActor::OneParamDelegateFunc); // 绑定有一个int32参数的委托函数
TwoParamsDelegate.BindUObject(this, &AMyDelegateActor::TwoParamsDelegateFunc); // 绑定有一个int32参数和一个FString参数的委托函数
RetValDelegate.BindUObject(this, &AMyDelegateActor::RetValDelegateFunc); // 绑定有返回值的委托函数
}
// Called when the game starts or when spawned
void AMyDelegateActor::BeginPlay()
{
Super::BeginPlay();
NoParamDelegate.Execute(); // 执行无参委托函数
OneParamDelegate.Execute(1); // 执行有一个int32参数的委托函数
TwoParamsDelegate.Execute(1, TEXT("TwoParamsDelegate")); // 执行有一个int32参数和一个FString参数的委托函数
int32 RetVal = RetValDelegate.Execute(); // 执行有返回值的委托函数
UE_LOG(LogTemp, Warning, TEXT("RetVal:%d"), RetVal);
}
// Called every frame
void AMyDelegateActor::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
void AMyDelegateActor::NoParamDelegateFunc()
{
UE_LOG(LogTemp, Warning, TEXT("NoParamDelegateFunc"));
}
void AMyDelegateActor::OneParamDelegateFunc(int32 Param)
{
UE_LOG(LogTemp, Warning, TEXT("OneParamDelegateFunc Param:%d"), Param);
}
void AMyDelegateActor::TwoParamsDelegateFunc(int32 Param1, FString Param2)
{
UE_LOG(LogTemp, Warning, TEXT("TwoParamsDelegateFunc Param1:%d Param2:%s"), Param1, *Param2);
}
int32 AMyDelegateActor::RetValDelegateFunc()
{
UE_LOG(LogTemp, Warning, TEXT("RetValDelegateFunc"));
return 1;
}
然后把C++类 MyDelegateActor 拖到场景中，运行
多播委托
多播委托（代理） 可以绑定绑定多个函数
创建一个C++类 MyDelegateActor
MyDelegateActor.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "MyDelegateActor.generated.h"
// 多播委托代理
DECLARE_MULTICAST_DELEGATE(NoParamMulticastDelegate); // 声明一个无参多播委托
DECLARE_MULTICAST_DELEGATE_OneParam(OneParamMulticastDelegate, int32); // 声明一个有一个int32参数的多播委托
DECLARE_MULTICAST_DELEGATE_TwoParams(TwoParamsMulticastDelegate, int32, FString); // 声明一个有一个int32参数和一个FString参数的多播委托
UCLASS()
class DEMO_API AMyDelegateActor : public AActor
{
GENERATED_BODY()
public:
// Sets default values for this actor's properties
AMyDelegateActor();
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
/***** 多播委托代理 ******/
NoParamMulticastDelegate NoParamMulticastDelegate; // 声明一个无参多播委托
OneParamMulticastDelegate OneParamMulticastDelegate; // 声明一个有一个int32参数的多播委托
TwoParamsMulticastDelegate TwoParamsMulticastDelegate; // 声明一个有一个int32参数和一个FString参数的多播委托
void NoParamMulticastDelegateFunc(); // 无参多播委托函数
void NoParamMulticastDelegateFunc2();
void OneParamMulticastDelegateFunc(int32 Param); // 有一个int32参数的多播委托函数
void OneParamMulticastDelegateFunc2(int32 Param);
void TwoParamsMulticastDelegateFunc(int32 Param1, FString Param2); // 有一个int32参数和一个FString参数的多播委托函数
void TwoParamsMulticastDelegateFunc2(int32 Param1, FString Param2);
};
MyDelegateActor.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "MyDelegateActor.h"
// Sets default values
AMyDelegateActor::AMyDelegateActor()
{
// 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;
/***** 多播委托代理 ******/
NoParamMulticastDelegate.AddUObject(this, &AMyDelegateActor::NoParamMulticastDelegateFunc); // 绑定无参多播委托函数
NoParamMulticastDelegate.AddUObject(this, &AMyDelegateActor::NoParamMulticastDelegateFunc2);
OneParamMulticastDelegate.AddUObject(this, &AMyDelegateActor::OneParamMulticastDelegateFunc); // 绑定有一个int32参数的多播委托函数
OneParamMulticastDelegate.AddUObject(this, &AMyDelegateActor::OneParamMulticastDelegateFunc2);
TwoParamsMulticastDelegate.AddUObject(this, &AMyDelegateActor::TwoParamsMulticastDelegateFunc); // 绑定有一个int32参数和一个FString参数的多播委托函数
TwoParamsMulticastDelegate.AddUObject(this, &AMyDelegateActor::TwoParamsMulticastDelegateFunc2);
}
// Called when the game starts or when spawned
void AMyDelegateActor::BeginPlay()
{
Super::BeginPlay();
/***** 多播委托代理 ******/
NoParamMulticastDelegate.Broadcast(); // 执行无参多播委托函数
OneParamMulticastDelegate.Broadcast(1); // 执行有一个int32参数的多播委托函数
TwoParamsMulticastDelegate.Broadcast(1, TEXT("TwoParamsDelegate")); // 执行有一个int32参数和一个FString参数的多播委托函数
}
// Called every frame
void AMyDelegateActor::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
/***** 多播委托代理 ******/
void AMyDelegateActor::NoParamMulticastDelegateFunc()
{
UE_LOG(LogTemp, Warning, TEXT("NoParamMulticastDelegateFunc"));
}
void AMyDelegateActor::NoParamMulticastDelegateFunc2()
{
UE_LOG(LogTemp, Warning, TEXT("NoParamMulticastDelegateFunc2"));
}
void AMyDelegateActor::OneParamMulticastDelegateFunc(int32 Param)
{
UE_LOG(LogTemp, Warning, TEXT("OneParamMulticastDelegateFunc Param:%d"), Param);
}
void AMyDelegateActor::OneParamMulticastDelegateFunc2(int32 Param)
{
UE_LOG(LogTemp, Warning, TEXT("OneParamMulticastDelegateFunc2 Param:%d"), Param);
}
void AMyDelegateActor::TwoParamsMulticastDelegateFunc(int32 Param1, FString Param2)
{
UE_LOG(LogTemp, Warning, TEXT("TwoParamsMulticastDelegateFunc Param1:%d Param2:%s"), Param1, *Param2);
}
void AMyDelegateActor::TwoParamsMulticastDelegateFunc2(int32 Param1, FString Param2)
{
UE_LOG(LogTemp, Warning, TEXT("TwoParamsMulticastDelegateFunc2 Param1:%d Param2:%s"), Param1, *Param2);
}
打印日志
动态多播代理
动态多播委托代理 区别在于可以暴露给蓝图，在蓝图中进行事件绑定, 一定要是F开头
还有就是参数和参数名一定要配合使用
创建一个C++类 MyDelegateActor
MyDelegateActor.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "MyDelegateActor.generated.h"
// 动态多播委托代理 区别在于可以暴露给蓝图，在蓝图中进行事件绑定, 一定要是F开头
DECLARE_DYNAMIC_MULTICAST_DELEGATE(FNoParamDynamicMulticastDelegate); // 声明一个无参多播委托
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOneParamDynamicMulticastDelegate, FString, ParamStr); // 声明一个有一个int32参数的多播委托
DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FTwoParamsDynamicMulticastDelegate, int32, ParamInt, FString, ParamStr); // 声明一个有一个int32参数和一个FString参数的多播委托
UCLASS()
class DEMO_API AMyDelegateActor : public AActor
{
GENERATED_BODY()
public:
// Sets default values for this actor's properties
AMyDelegateActor();
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
/***** 动态多播委托代理 ******/
UPROPERTY(BlueprintAssignable, Category = "MyDelegate")
FNoParamDynamicMulticastDelegate NoParamDynamicMulticastDelegate; // 声明一个无参多播委托
UPROPERTY(BlueprintAssignable, Category = "MyDelegate")
FOneParamDynamicMulticastDelegate OneParamDynamicMulticastDelegate; // 声明一个有一个int32参数的多播委托
UPROPERTY(BlueprintAssignable, Category = "MyDelegate")
FTwoParamsDynamicMulticastDelegate TwoParamsDynamicMulticastDelegate; // 声明一个有一个int32参数和一个FString参数的多播委托
};
MyDelegateActor.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "MyDelegateActor.h"
// Sets default values
AMyDelegateActor::AMyDelegateActor()
{
// 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 AMyDelegateActor::BeginPlay()
{
Super::BeginPlay();
/***** 执行动态多播委托代理 ******/
NoParamDynamicMulticastDelegate.Broadcast();
OneParamDynamicMulticastDelegate.Broadcast(TEXT("OneParamsDelegate"));
TwoParamsDynamicMulticastDelegate.Broadcast(1, TEXT("TwoParamsDelegate"));
}
// Called every frame
void AMyDelegateActor::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
编译之后，创建蓝图类BP_MyDelegateActor
在蓝图中实现
打印日志
