將實現了介面類的ACTOR類進行型別轉換，將其轉換為介面類。

沿用之前的（十三、十四）工程。

在GAMEBASE的標頭檔案裡新增如下程式碼：

1 TArray<IMyInterface*>actorlist;

在GAMEBASE原始檔裡的程式碼：

 1 // Copyright 1998-2019 Epic Games, Inc. All Rights Reserved.
 2 
 3 
 4 #include "MyProject7_INTERFACEGameModeBase.h"
 5 #include "MyActor.h"
 6 #include "MyProject7_INTERFACE/MyInterface.h
 
"
 7 #include "Engine.h"
 8 
 9 
10 void AMyProject7_INTERFACEGameModeBase::BeginPlay() {
11     Super::BeginPlay();
12 
13     FTransform spawnLocation;
14     //FTransform trans = FTransform(FRotator(0), FVector(0), FVector(0));
15     for (int i = 0; i < 10; i++) {
16     AMyActor* spawnActor = GetWorld()->SpawnActor<AMyActor>(AMyActor::StaticClass(), spawnLocation);
 
17 
18     UClass* actorClass = spawnActor->GetClass();
19 
20     if (actorClass->ImplementsInterface(UMyInterface::StaticClass())) {
21         GEngine->AddOnScreenDebugMessage(-1, 10, FColor::Red, TEXT("Implements the Interface"));
22        }
23     }
24 
25     for (TActorIterator<AActor>it(GetWorld(), AActor::StaticClass()); it; ++it) {  //用到了ACOTR的迭代器，it指標傳入兩個引數，意思是在世界關卡中找Actor類的物件，++it不能寫成it++。
 
26         IMyInterface* myinterface = Cast<IMyInterface>(*it);//將實現了介面類的ACTOR物件進行型別轉換。
27 
28         if (myinterface) {
29             actorlist.Add(myinterface); //將型別轉換成功的IMyInterface類的物件放入陣列。
30         }
31     }
32 
33     FString result = FString::Printf(TEXT("the numbers of the interface was Implemented %d"),actorlist.Num());
34 
35     GEngine->AddOnScreenDebugMessage(-1, 10, FColor::Blue, result);
36 
37 }

效果如下：