I can't understand this version of `fling` animati...

# compose

[Kazemihabib1996]

I can't understand this version of fling animation

fun AnimatedFloat.fling(
    startVelocity: Float,
    decay: DecayAnimation = ExponentialDecay(),
    adjustTarget: (Float) -> TargetAnimation?,
    onEnd: OnAnimationEnd? = null
)

it accepts a startVelocity and decay so far it makes sence.
but it also accepts an adjustTarget that's the what I can't understand, setting new target with new animation inside fling animation?

[matvei]

It can be used to adjust target calculated by the decay . For example, imagine you have some bounds and want to nicely fling to the bound, not at the random point where decay stopped it. That's when you can adjust target so fling will end where you need it to

[matvei]

One more example: you have BottomSheet that can be opened fullscreen, or half screen. You can implement it in the way that if user flings and your original target passed the certain threshold, you animate to the fullscreen bound, otherwise to the halfscreen

[Kazemihabib1996]

@matvei Thank you, nice explanation and example.
I've been thinking some how these animations are merged !!!! and that was confusing me.
but after your explanation and reading the source of it I realized it just uses the animation of adjustTarget if the targetAnimation is not null.

[matvei]

Yep, for most of the fling scenarios null will just work fine 🙂