UEC++委托

//添加HealthComponent组件，Character相当于一个容器
UPROPERTY(VisibleAnywhere,BlueprintReadOnly,Category="Health")
USHeathComponent* HealthComponent; //观察者引用发送者

​
//要绑定的函数参数要和声明委托的参数一致
//委托函数使用`UDELEGATE` 宏，支持与 `UFUNCTION` 相同的说明符。
//委托参数的变量类型后面要加 `,` 与变量命分隔开。和常规函数不同
UFUNCTION()
void OnHealthChange(USHeathComponent* HealthComponent, float Health, float HealthDelta, const class UDamageType* DamageType, class AController* InstigatedBy, AActor* DamageCauser);

//在创建HealthComponent对象后，绑定函数OnHealthChange函数到其委托OnHealthChange上（名字可以不相同），OnHealthChange函数执行具体的内容
HealthComponent->OnHealthChange.AddDynamic(this, &ASCharacter::OnHealthChange);

//无参无返回值
DECLARE_MULTICAST_DELEGATE(DelegateName);

//有参无返回值
DECLARE_MULTICAST_DELEGATE_ONEPARAM(DelegateName, Param1Type); //一个参数
DECLARE_MULTICAST_DELEGATE_<Num>PARAMS(DelegateName, Param1Type,...); //多参

//无参无返回值
DECLARE_EVENT(OwningType, EventName);

//有参无返回值
DECLARE_EVENT_ONEPARAM(OwningType, DelegateName, Param1Type); //一个参数
DECLARE_EVENT_<Num>PARAMS(OwningType, DelegateName, Param1Type,...); //多参

//动态单播（可以有返回值）
//无参，无返回值
DECLARE_DYNAMIC_DELEGATE(DelegateName) 
//有参，无返回值
DECLARE_DYNAMIC_DELEGATE_<Num>Params(DelegateName, Param1Type, ...)//多参
//无参，有返回值
DECLARE_DYNAMIC_DELEGATE_RetVal(RetValType, DelegateName)
//有参有返回值
DECLARE_DYNAMIC_DELEGATE_RetVal_<Num>Params(RetValType, DelegateName, Param1Type, Param2Type, ...)

//动态多播（无返回值）
//无参无返回值
DECLARE_DYNAMIC_MULTICAST_DELEGATE(DelegateName);
//有参，无返回值
DECLARE_DYNAMIC_MULTICAST_DELEGATE_<Num>Params(DelegateName, Param1Type, ...)//多参

#define BindDynamic( UserObject, FuncName ) __Internal_BindDynamic( UserObject, FuncName, STATIC_FUNCTION_FNAME( TEXT( #FuncName ) ) )
 
#define AddDynamic( UserObject, FuncName ) __Internal_AddDynamic( UserObject, FuncName, STATIC_FUNCTION_FNAME( TEXT( #FuncName ) ) )

// 定义委托样式
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FActorTrigger, const FString&, TriggerName);

//绑定事件函数
UFUNCTION(BlueprintCallable, Category = "Event")
void GlobalBindEvent(UserClass* Object, FString TriggerName, typename FActorTrigger::FDelegate::TMethodPtrResolver<UserClass>::FMethodPtr FuncPtr, FName FuncName);

//派发事件
UFUNCTION(BlueprintCallable, Category = "Event")
void GlobalDispatchEvent(FString TriggerName);

//清除所有事件
UFUNCTION(BlueprintCallable, Category = "Event")
void ClearAllEvents();

// 全局绑定事件
template< class UserClass >
void MyGameState::GlobalBindTriggerEvent(UserClass* Object, FString TriggerName, typename FActorTrigger::FDelegate::TMethodPtrResolver<UserClass>::FMethodPtr FuncPtr, FName FuncName) 
{
    FActorTrigger& Trigger = TriggerDelagates.FindOrAdd(TriggerName);
    Trigger.__Internal_AddDynamic(Object, FuncPtr, FuncName);
}

// 全局派发事件
void AMyGameState::GlobalDispatchEvent(FString TriggerName)
{
    if (TriggerName.Len() > 0)
    {
        FPlaceableActorTrigger* Trigger = TriggerDelagates.Find(TriggerName);
        if (Trigger)
        {
            Trigger->Broadcast(TriggerName);
        }
    }
}

// 清除事件
void AMyGameState::ClearAllEvents()
{
    for (auto DeleagtePair : TriggerDelagates)
    {
        DeleagtePair.Value.Clear();
    }
    TriggerDelagates.Empty();


}

/////////////////// 绑定事件 /////////////////////
#include "UserClass.h"
TriggerEventName = "MyTriggerEvent";

// 获取GameState
AMyGameState* myInstance = Cast<AMyGameState>(GetWorld()->GetGameState());
myInstance->GlobalBindTriggerEvent<UUserClass>(this, TriggerEventName, &UUserClass::OnMyTestFunction, FName(TEXT("OnMyTestFunction")));

/////////////////// 派发事件 /////////////////////
AMyGameState* myGameState = Cast<AMyGameState>(GetWorld()->GetGameState());
myGameState ->GlobalDispatchEvent(TriggerEventName);

template <typename... Args>
struct FMultiType {
    std::tuple<Args...> values;


    template<typename T>
    FMultiType(T value): values(value) {}


    template<typename T, typename... Rest>
    FMultiType(T arg, Rest... rest): values(arg, rest...) {}
};

////////////////序列化参数//////////////////
// 创建一个新的 JSON 对象
TSharedPtr<FJsonObject> MyJsonObject = MakeShareable(new FJsonObject);

// 向 JSON 对象中添加字段
MyJsonObject->SetStringField(TEXT("Name"), TEXT("John"));
MyJsonObject->SetNumberField(TEXT("Age"), 25);
MyJsonObject->SetBoolField(TEXT("IsStudent"), true);

// 将 JSON 对象转换为字符串
FString JsonString;
TSharedRef<TJsonWriter<>> Writer = TJsonWriterFactory<>::Create(&JsonString);
FJsonSerializer::Serialize(MyJsonObject.ToSharedRef(), Writer);

///////////////重新定义委托参数///////////////
// 定义委托样式
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FActorTrigger, const FString&, TriggerName, FString&, Prams);

////////////////反序列化参数//////////////////
// 传入参数为JsonString
TSharedPtr<FJsonObject> MyJsonObject;
TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(JsonString);
if (FJsonSerializer::Deserialize(Reader, MyJsonObject) && MyJsonObject.IsValid())
{
    // 反序列化成功
   
    // 获取字符串字段
    FString Name;
    MyJsonObject->TryGetStringField(TEXT("Name"), Name);

    // 获取数值字段
    float Age;
    MyJsonObject->TryGetNumberField(TEXT("Age"), Age);

    // 获取布尔字段
    bool IsStudent;
    MyJsonObject->TryGetBoolField(TEXT("IsStudent"), IsStudent);
}
else
{
    UE_LOG(LogTemp, Log, TEXT("Fail Deserialize JsonObject"));
}

// 存储整数类型的变量
FVariant Var = 123;

// 存储浮点数类型的变量
float FloatValue = 3.14f;
Var = FloatValue;

// 存储字符串类型的变量
FString StringValue = TEXT("Hello World");
Var = StringValue;

// 存储对象指针类型的变量
AActor* ActorPtr = GetWorld()->GetFirstPlayerController()->GetCharacter();
Var = FObjectPtr(ActorPtr);

// 存储枚举类型的变量
EMyEnum MyEnumValue = EMyEnum::Value1;
Var = MyEnumValue;

// 存储结构体类型的变量
FVector Location(1.0f, 2.0f, 3.0f);
Var = Location;

// 存储对象类型的变量
UClass* MyClass = UMyClass::StaticClass();
UMyClass* MyObj = NewObject<UMyClass>();
Var = FSoftObjectPath(MyClass->GetPathName() + TEXT(".") + MyObj->GetName());