mobven/HandyViewController

View controller transitioning allowing self-sizing presented view controller to be dismissed by swiping down.

View controller transitioning allowing self-sizing presented view controller to be dismissed by swiping down.

Examples

Requirements

• iOS 10.0+
• Xcode 11+
• Swift 5.2+

Installation

HandyViewController is distributed with Swift Package Manager which is the only official distribution tool by Apple. You can add HandyViewController to your project from Xcode's File > Swift Packages > Add Package Dependency menu with its github URL:

https://github.com/mobven/HandyViewController.git

Usage

Basically, to achieve HandyViewController presentation, you set transitioningDelegate of your view controller to HandyTransitioningDelegate. There are two options while initializing HandyTransitioningDelegate:

Content size

Presented view controller must have necessary constraints (from top to bottom) to allow HandyViewController to calculate its height.

let controller = storyboard!.instantiateViewController(withIdentifier: "ViewController")
let transitioningDelegate = HandyTransitioningDelegate(from: self, to: controller)
controller.modalPresentationStyle = .custom
controller.transitioningDelegate = transitioningDelegate
present(controller, animated: true)

Parameters

presented: View controller presenting HandyViewController.
presenting: View controller being presented.
contentMode: Content mode of HandyViewController.
syncViewHeightWithKeyboard: When the keyboard is showed, view scrolls up with the keyboard.
maxBackgroundOpacity: Change background dim opacity, set zero to turn it off.

Full Screen

View controller displayed full screen with a small padding in the top.

let controller = storyboard!.instantiateViewController(withIdentifier: "ViewController")
let transitioningDelegate = HandyTransitioningDelegate(from: self, to: controller, contentMode: .fullScreen)
controller.modalPresentationStyle = .custom
controller.transitioningDelegate = transitioningDelegate
present(controller, animated: true)

ScrollView events

If presented view controller contains any UIScrollView (eg. UITableView, UICollectionView) that has no specifed content height, allow HandyViewController to calculate its size by:

override func viewDidLoad() {
    super.viewDidLoad()
    registerHandyScrollView(tableView)
}

HandyViewController provides swipe-to-dismiss feature with scroll events. To achieve this behavior, in your presented view controller:

extension DetailsViewController: UIScrollViewDelegate {

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        handyScrollViewDidScroll(scrollView)
    } 

    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint,
                                   targetContentOffset: UnsafeMutablePointer<CGPoint>) {
        handyScrollViewWillEndDragging(scrollView, withVelocity: velocity)
    }
}

StackView usage

During usage we've faced content size calculation issues with presented view controllers containing UIStackView with fill distribution and alignment attributes. As a workaround to this issue HandyViewController adds an empty footer view to your stack view, which is invisible. You can achieve this by calling:

override func viewDidLoad() {
    super.viewDidLoad()
    registerHandyStackView(stackView)
}

What's next

• Allow view controller to interrupt swipe-to-dismiss.
• Tests in iPads.
• Swipe-to-dismiss indicator in top of the screen.
• iOS 13 modal presentation style for full-screen presented view controllers where presenting view controller frame decreased in background.
• Unit Tests.

---

Developed with 🖤 at Mobven