Create a SwiftUI Animation with the correct curve and duration from UIKit keyboard notifications

SwiftUIKeyboardAnimation.swift

func animation(from notification: Notification) -> Animation? {
	guard
	  let info = notification.userInfo,
	  let duration = info[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double,
	  let curveValue = info[UIResponder.keyboardAnimationCurveUserInfoKey] as? Int,
	  let uiKitCurve = UIView.AnimationCurve(rawValue: curveValue)
	else {
		return nil
	}

	let timing = UICubicTimingParameters(animationCurve: uiKitCurve)
	return Animation.timingCurve(
		Double(timing.controlPoint1.x),
		Double(timing.controlPoint1.y),
		Double(timing.controlPoint2.x),
		Double(timing.controlPoint2.y),
		duration: duration
	)
}

seem like UIKit keyboard animation ?

This was such a great lead, but on iOS 16 and 15, (or at least 16.4 and 15.5 that I’m testing on) the control points are just linear (0 to 1), you can to take the spring timing parameters instead.

        let timing = UICubicTimingParameters(animationCurve: uiKitCurve)
        if let springParams = timing.springTimingParameters,
           let mass = springParams.mass, let stiffness = springParams.stiffness, let damping = springParams.damping {
            return Animation.interpolatingSpring(mass: mass, stiffness: stiffness, damping: damping)
        } else {
            return Animation.easeOut(duration: duration) // this is the closest fallback
        }

with this helper

private extension UISpringTimingParameters {
    var mass: Double? {
        value(forKey: "mass") as? Double
    }
    var stiffness: Double? {
        value(forKey: "stiffness") as? Double
    }
    var damping: Double? {
        value(forKey: "damping") as? Double
    }
}

Still hard to make SwiftUI be exactly in sync, but this is closest I could get.

thx a lot, i'll try. 👍