UI Delegates
FOnTapStarted
Broadcast when a button is tapped.
DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnTapStarted);
Usage
Button->OnTapStarted.AddDynamic(this, &AMyActor::HandleButtonTap);
void AMyActor::HandleButtonTap()
{
// Handle button press
}
FOnStepperValueChanged
Broadcast when a stepper value changes.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnStepperValueChanged, int8, NewValue);
| Parameter | Type | Description |
|---|
NewValue | int8 | Direction: -1 (decrease), +1 (increase) |
FOnPad2DChanged
Broadcast when 2D pad direction changes.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPad2DChanged, FIntPoint, NewValue);
| Parameter | Type | Description |
|---|
NewValue | FIntPoint | Direction as (X, Y) where values are -1, 0, or 1 |
Service Delegates
FOnRecordingError
Broadcast when a recording error occurs.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FOnRecordingError,
FString, ErrorMessage, int32, ErrorCode);
| Parameter | Type | Description |
|---|
ErrorMessage | FString | Description of the error |
ErrorCode | int32 | Numeric error code |
Usage
Service->OnRecordingError.AddDynamic(this, &AMyActor::HandleRecordingError);
void AMyActor::HandleRecordingError(FString ErrorMessage, int32 ErrorCode)
{
UE_LOG(LogTemp, Error, TEXT("Recording error %d: %s"), ErrorCode, *ErrorMessage);
}
FOnCameraModeChanged
Broadcast when camera mode changes.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnCameraModeChanged, UClass*, ModeClass);
| Parameter | Type | Description |
|---|
ModeClass | UClass* | The new camera mode class |
FOnRecordingSaveFinished
Broadcast when recording save completes.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnRecordingSaveFinished, bool, Success);
| Parameter | Type | Description |
|---|
Success | bool | True if save succeeded |
FOnRecordingSaveProgress
Broadcast during save operation with progress.
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnRecordingSaveProgress, float, Progress);
| Parameter | Type | Description |
|---|
Progress | float | Progress value 0.0 to 1.0 |
Audio Delegates
FDelegateRenderAudio
Audio data callback for audio sources.
DECLARE_MULTICAST_DELEGATE_ThreeParams(FDelegateRenderAudio,
TArrayView<const float>/*PCM*/,
int32/*Channels*/,
ELCKAudioChannel/*Source*/);
typedef FDelegateRenderAudio::FDelegate FOnRenderAudioDelegate;
| Parameter | Type | Description |
|---|
PCM | TArrayView<const float> | Interleaved audio samples |
Channels | int32 | Number of audio channels |
Source | ELCKAudioChannel | Source channel type |
OnAudioDataDelegate is a single delegate, not multicast. Use BindLambda() to bind and ExecuteIfBound() to fire.
Usage
// Use BindLambda for single delegate (replaces any existing binding)
AudioSource->OnAudioDataDelegate.BindLambda([](
TArrayView<const float> PCM,
int32 Channels,
ELCKAudioChannel SourceChannel)
{
// PCM contains interleaved float samples
// Channels is typically 2 (stereo)
// SourceChannel identifies the audio type
});
// Fire the delegate from audio source implementation
OnAudioDataDelegate.ExecuteIfBound(PCM, 2, ELCKAudioChannel::Game);
Core Delegates
FOnLCKRecorderBoolResult
Result callback for async recording operations.
DECLARE_DELEGATE_OneParam(FOnLCKRecorderBoolResult, bool /*bSuccess*/);
Usage
Recorder->StartRecordingAsync(FOnLCKRecorderBoolResult::CreateLambda([](bool bSuccess) {
if (bSuccess)
UE_LOG(LogTemp, Log, TEXT("Recording started"));
else
UE_LOG(LogTemp, Error, TEXT("Failed to start"));
}));
FOnLCKRecorderProgress
Progress callback for save operations.
DECLARE_DELEGATE_OneParam(FOnLCKRecorderProgress, float /*Progress*/);
Usage
Recorder->StopRecordingAsync(
FOnLCKRecorderBoolResult::CreateLambda([](bool bSuccess) {
UE_LOG(LogTemp, Log, TEXT("Recording stopped"));
}),
FOnLCKRecorderProgress::CreateLambda([](float Progress) {
UE_LOG(LogTemp, Log, TEXT("Progress: %.1f%%"), Progress * 100.0f);
})
);
Binding Patterns
Dynamic Delegates
Lambda Binding
Removing Bindings
For UFUNCTION binding with Blueprint support:// Header
UFUNCTION()
void HandleButtonTap();
// Implementation
Button->OnTapStarted.AddDynamic(this, &AMyActor::HandleButtonTap);
For inline handlers:// Single delegate (non-multicast)
Source->OnAudioDataDelegate.BindLambda([](auto PCM, auto Channels, auto Source) {
// Process audio
});
// Multicast delegate
Button->OnTapStarted.AddLambda([this]() {
// Handle tap
});
// Dynamic delegate
Button->OnTapStarted.RemoveDynamic(this, &AMyActor::HandleButtonTap);
// Raw delegate with handle
FDelegateHandle Handle = Delegate.AddLambda(...);
Delegate.Remove(Handle);
