Give menus the option to veto closure

Source/StevesUEHelpers/Private/StevesUI/MenuBase.cpp

@@ -94,6 +94,7 @@ void UMenuBase::Open(bool bIsRegain)
     auto PC = GetOwningPlayer();    
     switch (InputModeSetting)
     {
+    default:
     case EInputModeChange::DoNotChange:
         break;
     case EInputModeChange::UIOnly:
@@ -109,6 +110,7 @@ void UMenuBase::Open(bool bIsRegain)
 
     switch (MousePointerVisibility)
     {
+    default:
     case EMousePointerVisibilityChange::DoNotChange:
         break;
     case EMousePointerVisibilityChange::Visible:
@@ -121,6 +123,7 @@ void UMenuBase::Open(bool bIsRegain)
 
     switch (GamePauseSetting)
     {
+    default:
     case EGamePauseChange::DoNotChange:
         break;
     case EGamePauseChange::Paused:
@@ -134,3 +137,19 @@ void UMenuBase::Open(bool bIsRegain)
     TakeFocusIfDesired();
     
 }
+
+bool UMenuBase::RequestClose(bool bWasCancel)
+{
+    if (ValidateClose(bWasCancel))
+    {
+        Close(bWasCancel);
+        return true;
+    }
+    return false;
+}
+
+bool UMenuBase::ValidateClose_Implementation(bool bWasCancel)
+{
+    // Default always pass
+    return true;
+}

Source/StevesUEHelpers/Private/StevesUI/MenuStack.cpp

@@ -149,7 +149,12 @@ bool UMenuStack::HandleKeyDownEvent(const FKeyEvent& InKeyEvent)
     if (BackKeys.Contains(Key))
     {
         // This is "Back"
-        PopMenu(true);
+        // Request close but allow veto
+        if (Menus.Num() > 0)
+        {
+            auto Top = Menus.Last();
+            Top->RequestClose(true);
+        }
         return true;
     }
     else if (InstantCloseKeys.Contains(Key))

Source/StevesUEHelpers/Public/StevesUI/MenuBase.h

@@ -59,6 +59,8 @@ protected:
 
     virtual void EmbedInParent();
 
+	UFUNCTION(BlueprintNativeEvent)
+	bool ValidateClose(bool bWasCancel);
 public:
     
     /**
@@ -70,12 +72,21 @@ public:
     UFUNCTION(BlueprintCallable)
     void Open(bool bIsRegainedFocus = false); 
     /**
-     * @brief Close this menu.
+     * @brief Request this menu to close. The menu can veto this request.
+     * @param bWasCancel Set this to true if the reason for closure was a cancellation action
+     * @return True if the request was approved
+     */
+    UFUNCTION(BlueprintCallable)
+    bool RequestClose(bool bWasCancel);
+    /**
+     * @brief Close this menu. This ALWAYS closes the menu, if you want it to be able to veto it, call RequestClose
      * @param bWasCancel Set this to true if the reason for closure was a cancellation action
      */
     UFUNCTION(BlueprintCallable)
     void Close(bool bWasCancel);
 
+    
+
     TWeakObjectPtr<UMenuStack> GetParentStack() const { return ParentStack; }
     virtual bool IsRequestingFocus_Implementation() const override { return bRequestFocus; }