Add useful functions for detecting whether a menu is the top of stack

Source/StevesUEHelpers/Private/StevesUI/MenuBase.cpp

@@ -27,6 +27,7 @@ void UMenuBase::AddedToStack(UMenuStack* Parent)
     ParentStack = MakeWeakObjectPtr(Parent);
 
     Open(false);
+    OnAddedToStack(Parent);
 }
 
 
@@ -45,11 +46,22 @@ void UMenuBase::InputModeChanged(EInputMode OldMode, EInputMode NewMode)
     }
 }
 
+bool UMenuBase::IsTopOfStack() const
+{
+    if (ParentStack.IsValid())
+    {
+        return ParentStack->GetTopMenu() == this;
+    }
+
+    return true;
+}
+
 void UMenuBase::RemovedFromStack(UMenuStack* Parent)
 {
     // This works whether embedded or not
     RemoveFromParent();
     PreviousFocusWidget.Reset();
+    OnRemovedFromStack(Parent);
 }
 
 void UMenuBase::SupercededInStack(UMenuBase* ByMenu)
@@ -66,12 +78,13 @@ void UMenuBase::SupercededInStack(UMenuBase* ByMenu)
         if (bHideWhenSuperceded)
             SetVisibility(ESlateVisibility::Collapsed);
     }
+    OnSupercededInStack(ByMenu);
 }
 
 void UMenuBase::RegainedFocusInStack()
 {
     Open(true);
-    
+    OnRegainedFocusInStack();
 }
 
 void UMenuBase::EmbedInParent()
@@ -156,3 +169,19 @@ bool UMenuBase::ValidateClose_Implementation(bool bWasCancel)
     // Default always pass
     return true;
 }
+
+void UMenuBase::OnSupercededInStack_Implementation(UMenuBase* ByMenu)
+{
+}
+
+void UMenuBase::OnRegainedFocusInStack_Implementation()
+{
+}
+
+void UMenuBase::OnAddedToStack_Implementation(UMenuStack* Parent)
+{
+}
+
+void UMenuBase::OnRemovedFromStack_Implementation(UMenuStack* Parent)
+{
+}

Source/StevesUEHelpers/Private/StevesUI/MenuStack.cpp

@@ -269,6 +269,15 @@ void UMenuStack::RemoveFromParent()
 
 }
 
+UMenuBase* UMenuStack::GetTopMenu() const
+{
+    if (Menus.Num() > 0)
+    {
+        return Menus.Top();
+    }
+    return nullptr;
+}
+
 UMenuStack::UMenuStack()
 {
     // Default to enabling automatic focus for menus (can still be overridden in serialized properties)

Source/StevesUEHelpers/Public/StevesUI/MenuBase.h

@@ -62,6 +62,19 @@ protected:
 
 	UFUNCTION(BlueprintNativeEvent)
 	bool ValidateClose(bool bWasCancel);
+
+	/// Called when this menu is superceded by another menu being pushed on to this stack
+	UFUNCTION(BlueprintNativeEvent)
+	void OnSupercededInStack(UMenuBase* ByMenu);
+	/// Called when this menu is superceded by another menu being pushed on to this stack
+	UFUNCTION(BlueprintNativeEvent)
+	void OnRegainedFocusInStack();
+
+	UFUNCTION(BlueprintNativeEvent)
+	void OnAddedToStack(UMenuStack* Parent);
+	UFUNCTION(BlueprintNativeEvent)
+	void OnRemovedFromStack(UMenuStack* Parent);
+
 public:
     
     /**
@@ -96,4 +109,9 @@ public:
     void SupercededInStack(UMenuBase* ByMenu);
     void RegainedFocusInStack();
     void InputModeChanged(EInputMode OldMode, EInputMode NewMode);
+
+	/// Return whether this menu is currently at the top of the menu stack
+	/// Note: if this menu is not owned by a stack, will always return true
+	UFUNCTION(BlueprintCallable)
+	bool IsTopOfStack() const;
 };

Source/StevesUEHelpers/Public/StevesUI/MenuStack.h

@@ -139,6 +139,9 @@ public:
     virtual void PopMenuIfTop(UMenuBase* UiMenuBase, bool bWasCancel);
     virtual void RemoveFromParent() override;
 
+    /// Return the menu which is currently top of the stack
+    UFUNCTION(BlueprintCallable)
+    UMenuBase* GetTopMenu() const;
 
     UMenuStack();