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  3. UFieldNotificationLibrary

UFieldNotificationLibrary

The Field Notification system allows a user to know when a property value is modified at runtime (note that it can be a function return value).

API > API/Runtime > API/Runtime/Engine > API/Runtime/Engine/FieldNotification

Inheritance Hierarchy

References

   
Module Engine
Header /Engine/Source/Runtime/Engine/Public/FieldNotification/FieldNotificationLibrary.h
Include #include "FieldNotification/FieldNotificationLibrary.h"

Syntax

UCLASS (MinimalAPI)  
class UFieldNotificationLibrary : public UBlueprintFunctionLibrary

Remarks

The Field Notification system allows a user to know when a property value is modified at runtime (note that it can be a function return value). The class needs to implement the INotifyFieldValueChanged interface. The property' setter usually follows this pattern "if (new value != old value) assign the new value; broadcast that the value changed;". The Blueprint implementation handles that setter logic automatically with SetPropertyValueAndBroadcast. When a property value is modified by replication, the RepNotify will call BroadcastFieldValueChanged. A function can also be a Field Notify. The function needs to be const and return a single value.

Functions

  Type Name Description
Public function Static UFunction BlueprintCallable, Category, Meta void Broadcast that a list of Field values changed.
Public function Static UFunction BlueprintCallable, Category, Meta void Broadcast that the Field value changed.
Public function Static UFunction BlueprintCallable, Category, Meta customthunk, displayname bool

SetPropertyValueAndBroadcast ( bool NewValueByRef,
UPARAM(ref) const int32& OldValue,
UPARAM(ref) const int32& NewValue,
UObject* Object,
UObject* NetOwner,
bool bHasLocalRepNotify,
bool bShouldFlushDormancyOnSet,
bool bIsNetProperty
)

  
Public function Static UFunction BlueprintCallable, Category, Meta customthunk, displayname bool

SetPropertyValueAndBroadcastFields ( bool NewValueByRef,
UPARAM(ref) const int32& OldValue,
UPARAM(ref) const int32& NewValue,
UObject* Object,
UObject* NetOwner,
bool bHasLocalRepNotify,
bool bShouldFlushDormancyOnSet,
bool bIsNetProperty,
TArray< FFieldNotificationId > ExtraFieldIds
)

  

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