Answers for "present modal view controller in half size parent controller swift"

present modal view controller in half size parent controller swift

import UIKit

final class ViewControllerB: UIViewController {

lazy var backdropView: UIView = {
    let bdView = UIView(frame: self.view.bounds)
    bdView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
    return bdView
}()

let menuView = UIView()
let menuHeight = UIScreen.main.bounds.height / 2
var isPresenting = false

init() {
    super.init(nibName: nil, bundle: nil)
    modalPresentationStyle = .custom
    transitioningDelegate = self
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func viewDidLoad() {
    super.viewDidLoad()

    view.backgroundColor = .clear
    view.addSubview(backdropView)
    view.addSubview(menuView)

    menuView.backgroundColor = .red
    menuView.translatesAutoresizingMaskIntoConstraints = false
    menuView.heightAnchor.constraint(equalToConstant: menuHeight).isActive = true
    menuView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    menuView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    menuView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true

    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(ViewControllerB.handleTap(_:)))
    backdropView.addGestureRecognizer(tapGesture)
}

func handleTap(_ sender: UITapGestureRecognizer) {
    dismiss(animated: true, completion: nil)
}
}

extension ViewControllerB: UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning {
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return self
}

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return self
}

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
    return 1
}

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    let containerView = transitionContext.containerView
    let toViewController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)
    guard let toVC = toViewController else { return }
    isPresenting = !isPresenting

    if isPresenting == true {
        containerView.addSubview(toVC.view)

        menuView.frame.origin.y += menuHeight
        backdropView.alpha = 0

        UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: {
            self.menuView.frame.origin.y -= self.menuHeight
            self.backdropView.alpha = 1
        }, completion: { (finished) in
            transitionContext.completeTransition(true)
        })
    } else {
        UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: {
            self.menuView.frame.origin.y += self.menuHeight
            self.backdropView.alpha = 0
        }, completion: { (finished) in
            transitionContext.completeTransition(true)
        })
    }
}
}