一、創建接口
二、創建C++類
三、實現接口
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "UObject/Interface.h"
#include "ReactToTriggerInterface.generated.h"
/*
聲明接口類與聲明普通的類相似,但是任有兩個主要區別。
1、接口類使用UINTERFACE()而不是UCLASS()。
2、直接從UInterface而不是UObject繼承。
接口分為四種:
無返回值 無參數 被藍圖當做事件 不能被實現
無返回值 帶參數 被藍圖當做事件 不能被實現
有返回值 無參數 不能被當做事件 可以被實現
有返回值 帶參數 不能備當做事件 可以被實現
説明符:
BlueprintCallable 可以在藍圖中調用
BlueprintImplementableEvent 在C++可以聲明函數(不能定義，藍圖重載),在C++裏調用該函數，藍圖重載實現該函數
BlueprintNativeEvent 在C++可以聲明和定義函數,在C++裏調用該函數,藍圖重載實現該函數(藍圖可以重載或不重載C++父類函數)
*/
// This class does not need to be modified.
UINTERFACE(MinimalAPI)
class UReactToTriggerInterface : public UInterface
{
GENERATED_BODY()
};
/**
*
*/
class INTERFACE_API IReactToTriggerInterface
{
GENERATED_BODY()
// Add interface functions to this class. This is the class that will be inherited to implement this interface.
public:
//不能當做事件接口定義
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
bool ReactToHighNoon();
//不能當做事件接口定義
UFUNCTION(BlueprintCallable, BlueprintImplementableEvent, Category = "LVCate")
bool ReactToMidnight();
//可以當做事件接口實現
UFUNCTION(BlueprintCallable, BlueprintImplementableEvent, Category = "LVCate")
void FuncAsImplementableEvent();
//可以當做事件接口實現
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEvent();
//可以當做事件接口實現
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEventWithParam(int value);
};// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "ReactToTriggerInterface.h"
#include "AReactToTriggerCPPImp.generated.h"
UCLASS()
class INTERFACE_API AAReactToTriggerCPPImp : public AActor, public IReactToTriggerInterface
{
GENERATED_BODY()
public:
// Sets default values for this actor's properties
AAReactToTriggerCPPImp();
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
//實現接口
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
bool ReactToHighNoon();
virtual bool ReactToHighNoon_Implementation() override; //必須定義和實現這個函數
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEvent();
virtual void FuncAsNativeEvent_Implementation() override;
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEventWithParam(int value);
virtual void FuncAsNativeEventWithParam_Implementation(int value) override;
//自己定義的函數
UFUNCTION(BlueprintCallable, BlueprintImplementableEvent, Category = "LVCate")
void FuncAsImplementableEventCPPImp();
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEventCPPImp();
void FuncAsNativeEventCPPImp_Implementation();
UFUNCTION(BlueprintCallable, BlueprintNativeEvent, Category = "LVCate")
void FuncAsNativeEventWithParamCPPImp(int value);
void FuncAsNativeEventWithParamCPPImp_Implementation(int value);
};// Fill out your copyright notice in the Description page of Project Settings.
#include "AReactToTriggerCPPImp.h"
// Sets default values
AAReactToTriggerCPPImp::AAReactToTriggerCPPImp()
{
// 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 AAReactToTriggerCPPImp::BeginPlay()
{
Super::BeginPlay();
}
// Called every frame
void AAReactToTriggerCPPImp::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
bool AAReactToTriggerCPPImp::ReactToHighNoon_Implementation()
{
this->FuncAsNativeEventCPPImp();
return true;
}
void AAReactToTriggerCPPImp::FuncAsNativeEvent_Implementation()
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventWithParam_Implementation(int value)
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventCPPImp_Implementation()
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventWithParamCPPImp_Implementation(int value)
{
}四、在藍圖中調用接口
將新建的C++類拖到場景當中，選中添加藍圖，命名為AReactToTriggerCPPImp1_Blueprint。
打開AReactToTriggerCPPImp1_Blueprint，可以看到無返回值函數作為事件，不能被實現。
可以看到不能被當做事件，但是可以被實現的函數。
添加事件
實現ReactToMidnight、ReactToHighNoon
新建一個新的藍圖命名為NewBlueprint，拖入場景中，並打開藍圖。
新建一個變量React
點擊場景中的NewBlueprint
返回藍圖中
運行可以看到屏幕上的打印
運行結果
在C++類中調用接口
在AAReactToTriggerCPPImp.cpp中添加代碼
// Fill out your copyright notice in the Description page of Project Settings.
#include "AReactToTriggerCPPImp.h"
#include "Misc\AssertionMacros.h"
#include <Engine.h>
DEFINE_LOG_CATEGORY_STATIC(LV, Log, All);
// Sets default values
AAReactToTriggerCPPImp::AAReactToTriggerCPPImp()
{
// 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 AAReactToTriggerCPPImp::BeginPlay()
{
Super::BeginPlay();
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, "BeginPlay");
this->Execute_ReactToHighNoon(this);//運行藍圖中的ReactToHighNoon函數
}
// Called every frame
void AAReactToTriggerCPPImp::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
bool AAReactToTriggerCPPImp::ReactToHighNoon_Implementation()
{
UE_LOG(LV, Warning, TEXT("ReactToHighNoon_Implementation"));
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, "ReactToHighNoon_Implementation");
this->Execute_ReactToMidnight(this);//運行藍圖中的ReactToMidnight函數
//this->FuncAsNativeEventCPPImp();
return true;
}
void AAReactToTriggerCPPImp::FuncAsNativeEvent_Implementation()
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventWithParam_Implementation(int value)
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventCPPImp_Implementation()
{
}
void AAReactToTriggerCPPImp::FuncAsNativeEventWithParamCPPImp_Implementation(int value)
{
}編譯完後運行結果如下
創建C++類，命名MyActor。
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "AReactToTriggerCPPImp.h"
#include "MyActor.generated.h"
UCLASS()
class INTERFACE_API AMyActor : public AActor
{
GENERATED_BODY()
public:
// Sets default values for this actor's properties
AMyActor();
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
void IteratorCall(); //迭代調用
};
// Fill out your copyright notice in the Description page of Project Settings.
#include "MyActor.h"
#include <Engine.h>
#include <EngineUtils.h>
// Sets default values
AMyActor::AMyActor()
{
// 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 AMyActor::BeginPlay()
{
Super::BeginPlay();
IteratorCall();
}
// Called every frame
void AMyActor::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
void AMyActor::IteratorCall()
{
TActorIterator<AAReactToTriggerCPPImp> actorIt = TActorIterator<AAReactToTriggerCPPImp>(GetWorld()); //獲得迭代器
//遍歷迭代器
for (actorIt; actorIt; ++actorIt)
{
if (!actorIt)
{
continue;
}
AAReactToTriggerCPPImp* actor = *actorIt;
bool isImplementation = actor->GetClass()->ImplementsInterface(UReactToTriggerInterface::StaticClass());
if (isImplementation)
{
IReactToTriggerInterface* inter = Cast<IReactToTriggerInterface>(actor);
inter->Execute_ReactToHighNoon(actor);
}
}
}將MyActor拖入場景中並運行，結果如下。
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