RaajeevChandran

class ViewController: UIViewController {
    private let scrollView = UIScrollView()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemBackground
        setupScrollView()
    }
   
    private func setupScrollView() {

RaajeevChandran

class BottomSheetTransition: UIPercentDrivenInteractiveTransition {
    private var dismissalAnimator: UIViewPropertyAnimator?
    
    private var presentationAnimator: UIViewPropertyAnimator?
        
    private let animationDuration = 0.5
    
    private let dampingRatio: Double = 0.9
    
    var dismissFractionComplete: CGFloat {

RaajeevChandran

class BottomSheetTransitioningDelegate: NSObject {
    let transition: BottomSheetTransition
    
    override init() {
        self.transition = BottomSheetTransition()
    }
}

    
extension BottomSheetTransitioningDelegate: UIViewControllerTransitioningDelegate {

RaajeevChandran

class BottomSheetPresentationController: UIPresentationController {
    
    private let dismissThreshold: CGFloat = 0.3
    
    private let grabberView: UIView = {
        let view = UIView()
        view.frame.size = CGSize(width: 50, height: 3)
        view.backgroundColor = .lightGray
        return view
    }()

RaajeevChandran

override var frameOfPresentedViewInContainerView: CGRect {
    guard let containerView, let presentedView else {
        return super.frameOfPresentedViewInContainerView
    }
    
    let maximumWidth = containerView.bounds.width
    
    let maximumHeight = containerView.frame.height - containerView.safeAreaInsets.top - containerView.safeAreaInsets.bottom
    
    let fittingSize = CGSize(width: maximumWidth, height: UIView.layoutFittingCompressedSize.height)

RaajeevChandran

override func presentationTransitionWillBegin() {
    super.presentationTransitionWillBegin()
    
    containerView?.addSubview(dimmedBackgroundView)
    
    dimmedBackgroundView.backgroundColor = .black.withAlphaComponent(0.5)
    
    presentedView?.addSubview(grabberView)
    
    presentedViewController.transitionCoordinator?.animate(alongsideTransition: {

RaajeevChandran

override func containerViewDidLayoutSubviews() {
    super.containerViewDidLayoutSubviews()
    
    guard let presentedView, let containerView else {
        return
    }
    
    dimmedBackgroundView.frame = containerView.bounds
    
    grabberView.frame.origin.y = 8

RaajeevChandran

override func dismissalTransitionWillBegin() {
    super.dismissalTransitionWillBegin()
    
    presentedViewController.transitionCoordinator?.animate(alongsideTransition: { [weak self] _ in
        guard let self else { return }
        
        self.presentedView?.layer.cornerRadius = .zero
        self.dimmedBackgroundView.backgroundColor = .clear
    })
}

RaajeevChandran

extension BottomSheetPresentationController {
    private func setupInteraction() {
        guard let presentedView = presentedView else {
            return
        }
        
        func addGestureIfNeeded(_ gesture: UIGestureRecognizer, to view: UIView, delegate: UIGestureRecognizerDelegate? = nil) {
            if let recognizers = view.gestureRecognizers, recognizers.contains(gesture) {
                return
            }

RaajeevChandran

private func dismiss(withInteraction: Bool) {
    transitioningDelegate?.transition.wantsInteractiveStart = withInteraction
    presentedViewController.dismiss(animated: true)
}