[HELP] Custom Struct Property Editor Add Setter and Listener

Development Programming & Scripting C++
, , ,
1

I have been struggling with this for a while and would really appreciate some guidance.

The goal is to create a dropdown list/combo box that contains strings that the user can select in the editor. This is to extend details customization.

I have created a custom structure like so.


USTRUCT()
    struct FTaskComponentData
    {
    	GENERATED_BODY()
    
    	UPROPERTY(VisibleAnywhere)
    	TArray<FString>												Names;
    
    };

Then I have created a class to implement the IPropertyTypeCustomization like so:
(Header file):


class FTaskComponentDataCustomization : public IPropertyTypeCustomization
    {
    public:
    	static TSharedRef<IPropertyTypeCustomization> MakeInstance();
     
    	/** IPropertyTypeCustomization interface */
    	virtual void CustomizeHeader(TSharedRef<class IPropertyHandle> StructPropertyHandle, class FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& StructCustomizationUtils) override;
    	virtual void CustomizeChildren(TSharedRef<class IPropertyHandle> StructPropertyHandle, class IDetailChildrenBuilder& StructBuilder, IPropertyTypeCustomizationUtils& StructCustomizationUtils) override;
     
    private:
    	TSharedPtr<IPropertyHandle> UPropertyTaskNameHandle;
    
    	/** Visibility delegate for the various methods of calculating magnitude */
    	EVisibility GetPropertyVisibility(UProperty* InProperty) const;
    };

(Source file):


TSharedRef<IPropertyTypeCustomization> FTaskComponentDataCustomization::MakeInstance()
    {
    	return MakeShareable(new FTaskComponentDataCustomization());
    }
     
    void FTaskComponentDataCustomization::CustomizeHeader(TSharedRef<class IPropertyHandle> StructPropertyHandle, class FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& StructCustomizationUtils)
    {
    	uint32 NumChildren;
    	StructPropertyHandle->GetNumChildren(NumChildren);
     
    	for (uint32 ChildIndex = 0; ChildIndex < NumChildren; ++ChildIndex)
    	{
    		const TSharedRef< IPropertyHandle > ChildHandle = StructPropertyHandle->GetChildHandle(ChildIndex).ToSharedRef();
     
    		if (ChildHandle->GetProperty()->GetName() == TEXT("Names"))
    		{
    			UPropertyTaskNameHandle = ChildHandle;
    		}
    	}
     
    	check(UPropertyTaskNameHandle.IsValid());
    
    
    	static TArray< TSharedPtr<FString>> something;
    
    	something.Add(TSharedPtr<FString>(new FString("One")));
    	something.Add(TSharedPtr<FString>(new FString("Two")));
    	something.Add(TSharedPtr<FString>(new FString("Three")));
    
    
    	HeaderRow.NameContent()
    		
    			StructPropertyHandle->CreatePropertyNameWidget(LOCTEXT("Task", "Task Names"), LOCTEXT("IDK","IDK"), false, true, false)
    		]
    	.ValueContent()
    		.MinDesiredWidth(250)
    		
    			SNew(STextComboBox)
    			.OptionsSource(&something)
    		];
    }
     
    void FTaskComponentDataCustomization::CustomizeChildren(TSharedRef<class IPropertyHandle> StructPropertyHandle, class IDetailChildrenBuilder& StructBuilder, IPropertyTypeCustomizationUtils& StructCustomizationUtils)
    {
    }
     
    
    EVisibility FTaskComponentDataCustomization::GetPropertyVisibility(UProperty* InProperty) const {
    	return EVisibility::Visible;
    }

I have then included this custom structure in my component subclass like this:


UPROPERTY(EditAnywhere, Category = "Planning | Task")
    FTaskComponentData							TaskData;

I then register with the FPropertyEditorModule like so:


FPropertyEditorModule& PropertyModule = FModuleManager::LoadModuleChecked<FPropertyEditorModule>("PropertyEditor");
    
    	//Custom properties
    	PropertyModule.RegisterCustomPropertyTypeLayout("TaskComponentData", FOnGetPropertyTypeCustomizationInstance::CreateStatic(&FTaskComponentDataCustomization::MakeInstance));

At this point, the desired combo box shows up… I have 2 questions:

  1. How can I set TArray so that I can update the data members with different strings?

  2. How do I register the property change listener? Right now, none of the property change listeners are fired from my component when I try to select values from my combobox.

Or where do I got to dig up any of this functionality?

2

Not sure what you mean by this. Where will the options come from, and how frequently can they change?

Your combo box is not currently hooked up to your property in any way. You need to provide a handler by adding .OnSelectionChanged(…) after .OptionsSource(). In that handler, you take the item given and pass it to a call to UPropertyTaskNameHandle->SetValue().

Your setup is confusing though. Is FTaskComponentData supposed to hold a single string from the available options, or is it meant to represent the set of options? I’m assuming the former, in which case your property should not be an array.

3

Supposed to be a set of options. I would update the array source for the options and tell the combo box to update. When I use the SetValue function on the PropertyHandler, sometimes it succeeds and sometimes it fails. If it fails the editor for the component doesn’t even draw! is this intended behavior?