What determines the availability of unload / reload buttons for editor modules?

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1

I have been working on an editor module for a while now. I made some large changes to how the EditorMode and Toolkit sets up the UI Commands and the Slate UI today. At some point the Unload / Reload buttons disappeared from the Module window in the editor. I have noticed that additionally when I press Recompile it no longer disables the additional Mode tab as it used to do.

Is there a specific reason for this? Did something that I changed influece the type of module that I have? I have an additional module that only contains runtime classes. This has never had those buttons, but I can understand why.

Thanks.

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2

I ran into this in UE 4.15 too. Turns out having a class that inherits from UFactory in your module/plugin will remove the option to reload that plugin via the module window.

I was able to work around this by creating a separate module (ie, MyGameFactories) and putting my UFactory classes there. You still can’t reload the factory plugin, but your editor module will regain the ability to reload.

Hope that helps!

3

I’m analyzing the same issue.

In UnrealEngine\Engine\Source\Developer\ModuleUI\Private\SModuleUI.cpp I found the code below. This code is for the module window.

else if ( ColumnName == "ModuleActions" )
			{
				...
				// Reload button
				+ SHorizontalBox::Slot()
					.AutoWidth()
					.Padding( 2.0f, 0.0f )
					[
						SNew( SButton )
						.Visibility( Item.ToSharedRef(), &FModuleListItem::GetVisibilityBasedOnReloadableState )
						.Text( LOCTEXT("Reload", "Reload") )
						.OnClicked( Item.ToSharedRef(), &FModuleListItem::OnReloadClicked )
					]

And If follow the code in the same file, finally I can meet the function GetVisibilityBasedOnLoadedAndShutdownableState() through GetVisibilityBasedOnReloadableState()

EVisibility SModuleUI::FModuleListItem::GetVisibilityBasedOnLoadedAndShutdownableState() const
{
	if ( GIsSavingPackage || IsGarbageCollecting() )
	{
		return EVisibility::Hidden;
	}

	const bool bIsHotReloadable = FModuleManager::Get().DoesLoadedModuleHaveUObjects(ModuleName);
	const bool bCanShutDown = ( FModuleManager::Get().IsModuleLoaded(ModuleName)
								&& !bIsHotReloadable 
								&& FModuleManager::Get().GetModule(ModuleName)->SupportsDynamicReloading() );

	return bCanShutDown ? EVisibility::Visible : EVisibility::Hidden;
}


EVisibility SModuleUI::FModuleListItem::GetVisibilityBasedOnReloadableState() const
{
	return GetVisibilityBasedOnLoadedAndShutdownableState();
};

This function checks DoesLoadedModuleHaveUObjects() . I think that Having UObject or Not can affect the visibility of reload button.

4

Unload / Reload buttons will disappear for example if you use UPROPERTY, UENUM, and other things associated with the garbage collector

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