starting to add the hud in the sample

Source/CogSample/CogSampleTask_WaitAttributeChanged.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "AbilitySystemComponent.h"
+#include "Kismet/BlueprintAsyncActionBase.h"
+
+#include "CogSampleTask_WaitAttributeChanged.generated.h"
+
+DECLARE_DYNAMIC_MULTICAST_DELEGATE_ThreeParams(FOnAttributeChangedDelegate, FGameplayAttribute, Attribute, float, NewValue, float, OldValue)
+;
+/**
+ * Blueprint node to automatically register a listener for all attribute changes in an AbilitySystemComponent.
+ */
+UCLASS(BlueprintType, meta = (ExposedAsyncProxy = AsyncTask))
+class UCogSampleTask_WaitAttributeChanged : public UBlueprintAsyncActionBase
+{
+    GENERATED_BODY()
+public:
+
+    UPROPERTY(BlueprintAssignable)
+    FOnAttributeChangedDelegate OnAttributeChanged;
+
+    UFUNCTION(BlueprintCallable, meta = (BlueprintInternalUseOnly = "true"))
+    static UCogSampleTask_WaitAttributeChanged* ListenForAttributeChange(UAbilitySystemComponent* AbilitySystemComponent, FGameplayAttribute Attribute);
+
+    virtual void Activate() override;
+
+    UFUNCTION(BlueprintCallable)
+    void EndTask();
+
+protected:
+
+    UPROPERTY()
+    UAbilitySystemComponent* AbilitySystemComponent = nullptr;
+
+    FGameplayAttribute AttributeToListenFor;
+
+    void AttributeChanged(const FOnAttributeChangeData& Data);
+
+};