在UE4 C++工程中,当子类重写父类虚函数时,常常会见到Super类型,如下:
// Called when the game starts or when spawned
void AMyActor::BeginPlay()
{
Super::BeginPlay();
}
// Called every frame
void AMyActor::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
Super是父类的类型别名,其定义是:Typedef 父类名 子类名::Super。在子类中使用Super,是对父类成员函数、成员变量的调用。
下面举例说明:
分别创建父类AMyActor、子类AMyMyActor,在AMyActor中设置虚函数Content()和变量value:
//声明
public:
void virtual Content();
int value;
//定义
AMyActor::AMyActor()
{
PrimaryActorTick.bCanEverTick = true;
value = 1;
}
void AMyActor::Content()
{
GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, TEXT("This is MyActor"));
}
在子类中重写Content()函数:
//声明
public:
void virtual Content() override;
//定义
void AMyMyActor::Content()
{
Super::Content(); //Typedef AMyActor Super::AMyMyActor
GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, TEXT("This is MyMyActor"));
Super::value = 2;
GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, FString::Printf(TEXT("value = %d"), value));
}
结果是: