how to make collapsible/expandable views in swift - ios

Question

I created a collapsible/expandable form on android. please see GIF below
https://giphy.com/gifs/zVvcKtgT9QTaa1O29O
I'm trying to create something similar on ios, so far, i've already created the bottom sheet as seen below
Looking at this GIF https://gfycat.com/dismalbronzeblowfish, you'd notice i'm able to expand and collapse the views, but there's a big gap where the view used to be, the expected behavior is that the space collapses also with an animation
Below is the code for the bottom sheet
class BottomSheetViewController: UIViewController {
// holdView can be UIImageView instead
#IBOutlet weak var holdView: UIView!
#IBOutlet weak var left: UIButton!
#IBOutlet weak var right: UIButton!
#IBOutlet weak var pickupView: UIView!
#IBOutlet weak var deliveryView: UIView!
#IBOutlet weak var deliverydetailsView: UIView!
#IBOutlet weak var pickupDetailsVIew: UIControl!
let fullView: CGFloat = 100
var partialView: CGFloat {
return UIScreen.main.bounds.height - 300
}
override func viewDidLoad() {
super.viewDidLoad()
let gesture = UIPanGestureRecognizer.init(target: self, action: #selector(BottomSheetViewController.panGesture))
view.addGestureRecognizer(gesture)
let pickupTapGesture = UITapGestureRecognizer(target: self, action: #selector(pickupButton))
let deliveryTapGesture = UITapGestureRecognizer(target: self, action: #selector(deliveryButton))
pickupView.addGestureRecognizer(pickupTapGesture)
deliveryView.addGestureRecognizer(deliveryTapGesture)
pickupView.setBorder(radius: 5, color: .black)
deliveryView.setBorder(radius: 5, color: .black)
roundViews()
deliverydetailsView.isHidden = true
pickupDetailsVIew.isHidden = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
prepareBackgroundView()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
UIView.animate(withDuration: 0.6, animations: { [weak self] in
let frame = self?.view.frame
let yComponent = self?.partialView
self?.view.frame = CGRect(x: 0, y: yComponent!, width: frame!.width, height: frame!.height)
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func rightButton(_ sender: AnyObject) {
print("clicked")
}
#objc func pickupButton(_ sender: UITapGestureRecognizer) {
print("tap")
if pickupDetailsVIew.isHidden {
expand(pickupDetailsVIew)
collapse(deliverydetailsView)
} else {
collapse(pickupDetailsVIew)
}
}
#objc func deliveryButton(_ sender: UITapGestureRecognizer) {
print("tap")
if deliverydetailsView.isHidden {
expand(deliverydetailsView)
collapse(pickupDetailsVIew)
} else {
collapse(deliverydetailsView)
// if deliveryView.isHidden && pickupDetailsVIew.isHidden {
//
// }
}
}
func expand(_ view: UIView) {
view.isHidden = false
}
func collapse(_ view: UIView) {
view.isHidden = true
}
// #IBAction func close(_ sender: AnyObject) {
// UIView.animate(withDuration: 0.3, animations: {
// let frame = self.view.frame
// self.view.frame = CGRect(x: 0, y: self.partialView, width: frame.width, height: frame.height)
// })
// }
#objc func panGesture(_ recognizer: UIPanGestureRecognizer) {
let translation = recognizer.translation(in: self.view)
let velocity = recognizer.velocity(in: self.view)
let y = self.view.frame.minY
if ( y + translation.y >= fullView) && (y + translation.y <= partialView ) {
self.view.frame = CGRect(x: 0, y: y + translation.y, width: view.frame.width, height: view.frame.height)
recognizer.setTranslation(CGPoint.zero, in: self.view)
}
if recognizer.state == .ended {
var duration = velocity.y < 0 ? Double((y - fullView) / -velocity.y) : Double((partialView - y) / velocity.y )
duration = duration > 1.3 ? 1 : duration
UIView.animate(withDuration: duration, delay: 0.0, options: [.allowUserInteraction], animations: {
if velocity.y >= 0 {
self.view.frame = CGRect(x: 0, y: self.partialView, width: self.view.frame.width, height: self.view.frame.height)
} else {
self.view.frame = CGRect(x: 0, y: self.fullView, width: self.view.frame.width, height: self.view.frame.height)
}
}, completion: nil)
}
}
func roundViews() {
view.layer.cornerRadius = 5
holdView.layer.cornerRadius = 3
// left.layer.cornerRadius = 10
// right.layer.cornerRadius = 10
// left.layer.borderColor = UIColor(red: 0, green: 148/225, blue: 247.0/255.0, alpha: 1).cgColor
// left.layer.borderWidth = 1
view.clipsToBounds = true
}
func prepareBackgroundView(){
// let blurEffect = UIBlurEffect.init(style: .dark)
// let visualEffect = UIVisualEffectView.init(effect: blurEffect)
// let bluredView = UIVisualEffectView.init(effect: blurEffect)
// bluredView.contentView.addSubview(visualEffect)
//
// visualEffect.frame = UIScreen.main.bounds
// bluredView.frame = UIScreen.main.bounds
//
// view.insertSubview(bluredView, at: 0)
}
}
I need some help/pointers in the right direction from anyone who has done this before, or who knows how to do this
Thank you