Workaround for the problem that EnhancedInput does not tell you when contexts / mappings change

Source/StevesUEHelpers/Private/StevesGameSubsystem.cpp

@@ -22,6 +22,7 @@ void UStevesGameSubsystem::Initialize(FSubsystemCollectionBase& Collection)
     CreateInputDetector();
     InitTheme();
     InitForegroundCheck();
+    NotifyEnhancedInputMappingsChanged();
 #endif
 }
 
@@ -60,6 +61,17 @@ void UStevesGameSubsystem::DestroyInputDetector()
 #endif
 }
 
+void UStevesGameSubsystem::NotifyEnhancedInputMappingsChanged()
+{
+    // delay to ensure there's a tick in between which updates the mappings, it's not synchronous
+    auto DelayedFunc = [this]()
+    {
+        OnEnhancedInputMappingsChanged.Broadcast();
+    };
+    FTimerHandle TempHandle;
+    GetWorld()->GetTimerManager().SetTimer(TempHandle, FTimerDelegate::CreateLambda(DelayedFunc), 0.05, false);
+}
+
 void UStevesGameSubsystem::InitTheme()
 {
     DefaultUiTheme = LoadObject<UUiTheme>(nullptr, *DefaultUiThemePath, nullptr);

Source/StevesUEHelpers/Private/StevesUI/InputImage.cpp

@@ -12,12 +12,13 @@ TSharedRef<SWidget> UInputImage::RebuildWidget()
     auto GS = GetStevesGameSubsystem(GetWorld());
     if (GS && !bSubbedToInputEvents)
     {
+        bSubbedToInputEvents = true;
         GS->OnInputModeChanged.AddUniqueDynamic(this, &UInputImage::OnInputModeChanged);
         GS->OnButtonInputModeChanged.AddUniqueDynamic(this, &UInputImage::OnInputModeChanged);
         GS->OnAxisInputModeChanged.AddUniqueDynamic(this, &UInputImage::OnInputModeChanged);
+        GS->OnEnhancedInputMappingsChanged.AddUniqueDynamic(this, &UInputImage::OnEnhancedInputMappingsChanged);
     }
     
-    bSubbedToInputEvents = true;
     UpdateImage();
 
     return Ret;
@@ -36,6 +37,11 @@ void UInputImage::OnInputModeChanged(int ChangedPlayerIdx, EInputMode InputMode)
     }
 }
 
+void UInputImage::OnEnhancedInputMappingsChanged()
+{
+    MarkImageDirty();
+}
+
 void UInputImage::SetCustomTheme(UUiTheme* Theme)
 {
     CustomTheme = Theme;
@@ -120,10 +126,24 @@ void UInputImage::UpdateImage()
         
         if (Sprite)
         {
+            if (bHiddenBecauseBlank)
+            {
+                SetVisibility(OldVisibility);
+                bHiddenBecauseBlank = false;
+            }
             // Match size is needed incase size has changed
             // Need to make it update region in case inside a scale box or something else that needs to adjust
             SetBrushFromAtlasInterface(Sprite, true);
         }
+        else
+        {
+            if (IsVisible())
+            {
+                bHiddenBecauseBlank = true;
+                OldVisibility = GetVisibility();
+                SetVisibility(ESlateVisibility::Hidden);
+            }
+        }
     }
     bIsDirty = false;
     DelayUpdate = 0;
@@ -132,7 +152,7 @@ void UInputImage::UpdateImage()
 void UInputImage::MarkImageDirty()
 {
     bIsDirty = true;
-    DelayUpdate = 0.5f;
+    DelayUpdate = 0.1f;
 }
 
 // Tickables

Source/StevesUEHelpers/Public/StevesGameSubsystem.h

@@ -14,6 +14,7 @@
 #include "StevesGameSubsystem.generated.h"
 
 DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnInputModeChanged, int, PlayerIndex, EInputMode, InputMode);
+DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnEnhancedInputMappingsChanged);
 DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnWindowForegroundChanged, bool, bFocussed);
 
 /// Entry point for all the top-level features of the helper system
@@ -161,6 +162,12 @@ public:
     UPROPERTY(BlueprintAssignable)
     FOnInputModeChanged OnAxisInputModeChanged;
 
+    /// Event raised justr after the Enhanced Input mappings have changed
+    /// Right now, this has to be user-triggered via NotifyEnhancedInputMappingsChanged, because the Enhanced Input
+    /// plugin provides NO events to monitor it (sigh)
+    UPROPERTY(BlueprintAssignable)
+    FOnEnhancedInputMappingsChanged OnEnhancedInputMappingsChanged;
+    
     /// Event raised when the game window's foreground status changes
     UPROPERTY(BlueprintAssignable)
     FOnWindowForegroundChanged OnWindowForegroundChanged;
@@ -277,4 +284,12 @@ public:
     */
     FStevesTextureRenderTargetPoolPtr GetTextureRenderTargetPool(FName Name, bool bAutoCreate = true);
 
+    /**
+     * Notify this subsystem that changes have been made to the Enhanced Input mappings, e.g. adding or removing a context.
+     * Unfortunately, the Enhanced Input plugin currently provides NO WAY for us to monitor context changes automatically,
+     * so we need the user to tell us when they make a change.
+     * This call is however slightly delayed before being acted upon, because EI defers the rebuild of mappings until the next tick.
+     */
+    void NotifyEnhancedInputMappingsChanged();
+
 };

Source/StevesUEHelpers/Public/StevesUI/InputImage.h

@@ -46,6 +46,8 @@ protected:
     bool bSubbedToInputEvents = false;
     bool bIsDirty = true;
     float DelayUpdate = 0;
+    bool bHiddenBecauseBlank;
+    ESlateVisibility OldVisibility;
 
 public:
 
@@ -104,5 +106,7 @@ protected:
         
     UFUNCTION()
     void OnInputModeChanged(int ChangedPlayerIdx, EInputMode InputMode);
+    UFUNCTION()
+    void OnEnhancedInputMappingsChanged();
     
 };