Select component type in editor

[vikhik]

I am trying to let my designers assign a specific type of camera component in the editor rather than hard-coding which camera is being used.

(e.g. I don’t have their soon-to-exist custom camera component, and it might be a BP only one).

I have tried two methods based on threads in the answerhub

Method 1

This is based on the following thread:

• https://answers.unrealengine.com/questions/210068/editable-sub-object-pointers.html

1) Set up a new C++ Pawn with a Camera Component

	UPROPERTY(Category = "Camera", BlueprintReadWrite)
		TSubclassOf<UCameraComponent> Camera;

2) Add a Camera Component Type selection variable

	UPROPERTY(Category = "Camera", BlueprintReadWrite)
		UClass* CameraType;

3) Construct the given component type and assign it to the camera variable (in pawn constructor)

Camera = CreateDefaultSubobject<CameraType>(TEXT("Camera"));

Is something like this possible? I currently get the following error:

error C2974: 'UObject::CreateDefaultSubobject': invalid template argument for 'TReturnType', type expected

##Method 2

Based on this thread:

• https://answers.unrealengine.com/questions/211292/selecting-subclass-of-component-in-editor.html

1) Set up a new C++ Pawn with a Camera Component

	UPROPERTY(Category = "Camera", BlueprintReadWrite)
		UCameraComponent* Camera;		

2) Construct the given component type and assign it to the camera variable (in pawn constructor)

Camera = CreateDefaultSubobject<UCameraComponent>(TEXT("Camera"));

3) Create a blueprint derived from the C++ class (which is BlueprintType)

**4) Show Inherited Variables **

**5) Edit the Camera Component Type from the dropdown **

This doesn’t work, see the attached image:

[anonymous_user_41845f4a]

Hello ,

Can I assume that your custom camera component inherits from UCameraComponent? If this is the case, your first method is almost correct. You can remove the line about creating a UClass variable and replace the line in the 3rd step with:

Camera = CreateDefaultSubobject<UCameraComponent>(TEXT("Camera"));

After doing this, if you create a blueprint based off the pawn, you should see a “Camera” variable in the details panel. Due to the TSubclassOf, the dropdown should include CameraComponent and any class / blueprint that inherits from it.

You also may need to add the “EditAnywhere” specifier to the UPROPERTY declaration.

[vikhik]

The problem with that is now I get an error when compiling:

error C2679: binary '=': no operator found which takes a right-hand operand of type 'UCameraComponent *' (or there is no acceptable conversion)

The code I am using is:

.h:

	UPROPERTY(Category = "camera", BlueprintReadWrite, EditAnywhere)
		TSubclassOf<UCameraComponent> Camera;

.cpp constructor:

	Camera = CreateDefaultSubobject<UCameraComponent>(TEXT("Camera"));

Also, dereferencing or casting the created component doesn’t help, not sure how to solve this?

[anonymous_user_e9d92aa7]

UPROPERTY(Category = “Camera”, BlueprintReadWrite, EditAnywhere)
TSubclassOf CameraComponentType;

UPROPERTY(Category = "Camera", BlueprintReadOnly)
    UCameraComponent * CameraComponent;

ACustomPawn::ACustomPawn(const FObjectInitializer& ObjectInitializer): Super(ObjectInitializer)
{
    ObjectInitializer.CreateDefaultSubobject(CameraComponent, TEXT("Camera"), UCameraComponent::StaticClass(), CameraComponentType, false, false, false);
    
}

[anonymous_user_13399bb2]

So this works for selecting the type. Now, what do you need to do if you want to edit some UPROPERTY variables for the selected type?

[Koulounil]

Does’nt work for me. CameraComponentType still contains its default value while in constructor.

It seems to me that we cannot access a property value edited in editor while still in constructor. And the problem is that CreateDefaultSubObject can only be executed in constructor. That’s the catch.

If any one knows a way to directly get the modified value of a property while still in constructor or a way to cleanly replace a component that was first created as a DefaultSubObject, I think it would work :p.

By the way, there was a missing “*” before CameraComponentType which in CreateDefaultSubObject which caused a crash to desktop. Took me a while to find out :

ObjectInitializer.CreateDefaultSubobject(CameraComponent, TEXT("Camera"), UCameraComponent::StaticClass(), *CameraComponentType, false, false, false);

[Koulounil]

For this, you need “EditInlineNew” as specifier of your base C++ class and “EditAnyWhere” as specifier of the UProperty:

UCLASS(EditInlineNew) class XXXX UCameraComponent : public UGameplayComponent

And

UPROPERTY(Category = "Camera", BlueprintReadOnly, EditAnyWhere) UCameraComponent * CameraComponent;

[Koulounil]

Well I found a solution (the upvoted answer is 5 years old and does not work anymore).

UPROPERTY(Category = "Camera", BlueprintReadWrite, EditAnywhere)
TSubclassOf<UCameraComponent> CameraComponentType;
     
UPROPERTY(Category = "Camera", BlueprintReadOnly)
UCameraComponent * CameraComponent;

ACustomPawn::ACustomPawn(): Super()
	{
	// Get the object as modified in editor
	ACustomPawn* DefaultObject = Cast<ACustomPawn>(this->GetClass()->GetDefaultObject());

	// Get value of sub class to use
	TSubclassOf<UCameraComponent> DefaultClass = DefaultObject->CameraComponentType;
	if (DefaultClass)
	{
		CameraComponent = Cast<UCameraComponent>(this->CreateDefaultSubobject(TEXT("Camera"), UCameraComponent::StaticClass(), *DefaultClass, true, false, false));
	}         
}

I’m not sure it’s the simplest, but at least it works (been looking for it for 15 hours).

[anonymous_user_a95ffae1]

you mean DefaultClass instead of CameraComponentType in line 16

tried, but doesn’t work…

• pointer type is still UCameraComponent;
• execution of subclassed component crashes the engine…

[Koulounil]

You’re right. Thanks for your attention, I’ve just corrected it.