128 lines
4.6 KiB
Swift
128 lines
4.6 KiB
Swift
// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.
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import UIKit
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import SignalUtilitiesKit
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// MARK: - InteractivelyDismissableViewController
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protocol InteractivelyDismissableViewController: UIViewController {
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func performInteractiveDismissal(animated: Bool)
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}
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// MARK: - InteractiveDismissDelegate
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protocol InteractiveDismissDelegate: AnyObject {
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func interactiveDismissUpdate(_ interactiveDismiss: UIPercentDrivenInteractiveTransition, didChangeTouchOffset offset: CGPoint)
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func interactiveDismissDidFinish(_ interactiveDismiss: UIPercentDrivenInteractiveTransition)
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}
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// MARK: - MediaInteractiveDismiss
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class MediaInteractiveDismiss: UIPercentDrivenInteractiveTransition {
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var interactionInProgress = false
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weak var interactiveDismissDelegate: InteractiveDismissDelegate?
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private weak var targetViewController: InteractivelyDismissableViewController?
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init(targetViewController: InteractivelyDismissableViewController) {
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super.init()
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self.targetViewController = targetViewController
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}
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public func addGestureRecognizer(to view: UIView) {
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let gesture: DirectionalPanGestureRecognizer = DirectionalPanGestureRecognizer(direction: .vertical, target: self, action: #selector(handleGesture(_:)))
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// Allow panning with trackpad
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if #available(iOS 13.4, *) { gesture.allowedScrollTypesMask = .continuous }
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view.addGestureRecognizer(gesture)
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}
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// MARK: - Private
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private var fastEnoughToCompleteTransition = false
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private var farEnoughToCompleteTransition = false
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private var lastProgress: CGFloat = 0
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private var lastIncreasedProgress: CGFloat = 0
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private var shouldCompleteTransition: Bool {
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if farEnoughToCompleteTransition { return true }
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if fastEnoughToCompleteTransition { return true }
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return false
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}
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@objc private func handleGesture(_ gestureRecognizer: UIScreenEdgePanGestureRecognizer) {
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guard let coordinateSpace = gestureRecognizer.view?.superview else { return }
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if case .began = gestureRecognizer.state {
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gestureRecognizer.setTranslation(.zero, in: coordinateSpace)
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}
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let totalDistance: CGFloat = 100
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let velocityThreshold: CGFloat = 500
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switch gestureRecognizer.state {
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case .began:
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interactionInProgress = true
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targetViewController?.performInteractiveDismissal(animated: true)
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case .changed:
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let velocity = abs(gestureRecognizer.velocity(in: coordinateSpace).y)
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if velocity > velocityThreshold {
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fastEnoughToCompleteTransition = true
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}
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let offset = gestureRecognizer.translation(in: coordinateSpace)
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let progress = abs(offset.y) / totalDistance
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// `farEnoughToCompleteTransition` is cancelable if the user reverses direction
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farEnoughToCompleteTransition = (progress >= 0.5)
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// If the user has reverted enough progress then we want to reset the velocity
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// flag (don't want the user to start quickly, slowly drag it back end end up
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// dismissing the screen)
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if (lastIncreasedProgress - progress) > 0.2 || progress < 0.05 {
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fastEnoughToCompleteTransition = false
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}
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update(progress)
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lastIncreasedProgress = (progress > lastProgress ? progress : lastIncreasedProgress)
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lastProgress = progress
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interactiveDismissDelegate?.interactiveDismissUpdate(self, didChangeTouchOffset: offset)
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case .cancelled:
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interactiveDismissDelegate?.interactiveDismissDidFinish(self)
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cancel()
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interactionInProgress = false
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farEnoughToCompleteTransition = false
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fastEnoughToCompleteTransition = false
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lastIncreasedProgress = 0
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lastProgress = 0
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case .ended:
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if shouldCompleteTransition {
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finish()
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}
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else {
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cancel()
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}
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interactiveDismissDelegate?.interactiveDismissDidFinish(self)
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interactionInProgress = false
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farEnoughToCompleteTransition = false
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fastEnoughToCompleteTransition = false
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lastIncreasedProgress = 0
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lastProgress = 0
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default:
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break
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}
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}
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}
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