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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

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.

   
Name UFieldNotificationLibrary
Type class
Header File /Engine/Source/Runtime/Engine/Public/FieldNotification/FieldNotificationLibrary.h
Include Path #include "FieldNotification/FieldNotificationLibrary.h"

Syntax

UCLASS (MinimalAPI)  
class UFieldNotificationLibrary : public UBlueprintFunctionLibrary

Inheritance Hierarchy

Functions

Static

Name Remarks Include Path Unreal Specifiers

static void BroadcastFieldsValueChanged ( UObject* Object,
TArray< FFieldNotificationId > FieldIds
)

 Broadcast that a list of Field values changed. FieldNotification/FieldNotificationLibrary.h
  • BlueprintCallable
  • Category="FieldNotification"
  • Meta=(FieldNotifyInterfaceParam="Object", DisplayName="Broadcast Fields Value Changed")

static void BroadcastFieldValueChanged ( UObject* Object,
FFieldNotificationId FieldId
)

 Broadcast that the Field value changed. FieldNotification/FieldNotificationLibrary.h
  • BlueprintCallable
  • Category="FieldNotification"
  • Meta=(FieldNotifyInterfaceParam="Object", DisplayName="Broadcast Field Value Changed")

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

   FieldNotification/FieldNotificationLibrary.h
  • BlueprintCallable
  • CustomThunk
  • DisplayName="Set w/ Broadcast"
  • Category="FieldNotification"
  • Meta=(CustomStructureParam="NewValue,OldValue", FieldNotifyInterfaceParam="Object", BlueprintInternalUseOnly="true")

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

   FieldNotification/FieldNotificationLibrary.h
  • BlueprintCallable
  • CustomThunk
  • DisplayName="Set w/ Broadcast"
  • Category="FieldNotification"
  • Meta=(CustomStructureParam="NewValue,OldValue", FieldNotifyInterfaceParam="Object", BlueprintInternalUseOnly="true")

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