Can I use BindAction with lambda?

Community Community & Industry Discussion
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1

Why it’s not possible wirte this:

InputComponent->BindAction( "Grow", IE_Pressed, [ this ]()
{
    isGrowing = true;
} );

I’ve to write something like:

InputComponent->BindAction( "Grow", IE_Pressed, this, &AMyPawn::OnStartGrowing );

Thanks in advice!

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2

Too my knowledge, and I could be wrong; you are only able to use lambda on certain delegates, and only as a static function pointer. I think it would be good for BindAction, but the devs would need to sort that out, or create a class inheriting from UInputComponent and overriding BindAction.

3

Not using BindAction per se, but if you look at how BindAction is implemented, you can use the same tools to do what you’re asking:

FInputActionBinding GrowPressedAB( "Grow", IE_Pressed );

GrowPressedAB.ActionDelegate.GetDelegateForManualSet().BindLambda( [this]()
{
	isGrowing = true;
});

InputComponent->AddActionBinding( GrowPressedAB );
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4

Been a while since you left this but I just needed to say thank you because this helped solve my exact problem. Gratitude.

5

This doesn’t seem to be possible for the Enhanced Input, anymore.

FEnhancedInputActionEventDelegateBinding<void()> Binding(Action, ETriggerEvent::Triggered); // doesn't accept FName
Binding.Delegate. ??? // doesn't have `GetDelegateForManualSet`
Cast<UEnhancedInputComponent>(InputComponent)-> ??? // doesn't have a way to add `FEnhancedInputActionEventDelegateBinding`
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6

i switched to templated functions now, i.e. non-type template parameters, to a similar effect.

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7

this would work, but doesnt account for the InputActionValue that is passed from the InputComponent

EDIT: im dumb. this does work perfectly. to get the FInputActionValue passed, all you have to do is ensure the template function is inside the CPP file AND have it as a parameter within the function. the BindAction will automatically pass the FInputActionValue if present

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8

@rubm123 Thank you!

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