Not able to remove custom UIView from SuperView - ios

Question

This is extremely odd. I am trying to remove the view from superview when I drag the view to either left or right. If the view doesn't contain any subviews then I am easily able to remove the view from the superView by using this card.removeFromSuperview() - however, what I have noticed is that if add two views as subviews inside the card view then I am not able to remove it from superView and the entire thing goes bezerk.
Here is the card view class:
class MainSwipeCardView: UIView {
//MARK: - Properties
var swipeView = UIView()
var shadowView = UIView()
var text: String?
var label = UILabel()
var bgColor : UIColor? {
didSet {
swipeView.backgroundColor = bgColor
}
}
var cardsarraydata : CardDataModel? {
didSet {
bgColor = cardsarraydata?.backgroundColor
label.text = cardsarraydata?.title
}
}
var delegate : CardDelegate?
//MARK :- Init
override init(frame: CGRect) {
super.init(frame: .zero)
backgroundColor = .clear
configureShadowView()
configureSwipeView()
configureLabelView()
addPanGestureOnCards()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
//MARK: - Configurations
func configureShadowView() {
shadowView.backgroundColor = .clear
shadowView.layer.shadowColor = UIColor.black.cgColor
shadowView.layer.shadowOffset = CGSize(width: 0, height: 0)
shadowView.layer.shadowOpacity = 0.8
shadowView.layer.shadowRadius = 4.0
addSubview(shadowView)
shadowView.translatesAutoresizingMaskIntoConstraints = false
shadowView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
shadowView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
shadowView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
shadowView.topAnchor.constraint(equalTo: topAnchor).isActive = true
}
func configureSwipeView() {
swipeView.layer.cornerRadius = 15
swipeView.clipsToBounds = true
shadowView.addSubview(swipeView)
swipeView.translatesAutoresizingMaskIntoConstraints = false
swipeView.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
swipeView.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
swipeView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
swipeView.topAnchor.constraint(equalTo: topAnchor).isActive = true
}
func configureLabelView() {
swipeView.addSubview(label)
label.backgroundColor = .white
label.textColor = .black
label.textAlignment = .center
label.font = UIFont.systemFont(ofSize: 18)
label.translatesAutoresizingMaskIntoConstraints = false
label.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
label.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
label.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
label.heightAnchor.constraint(equalToConstant: 85).isActive = true
}
func addPanGestureOnCards() {
self.isUserInteractionEnabled = true
addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(handlePanGesture)))
}
//MARK: - Handlers
#objc func handlePanGesture(sender: UIPanGestureRecognizer){
let card = sender.view as! MainSwipeCardView
let point = sender.translation(in: self)
let centerOfParentContainer = CGPoint(x: self.frame.width / 2, y: self.frame.height / 2)
card.center = CGPoint(x: centerOfParentContainer.x + point.x, y: centerOfParentContainer.y + point.y)
switch sender.state {
case .ended:
if (card.center.x) > 400 {
delegate?.swipeDidEnd(on: card)
UIView.animate(withDuration: 0.2) {
card.center = CGPoint(x: centerOfParentContainer.x + point.x + 200, y: centerOfParentContainer.y + point.y + 75)
card.alpha = 0
self.layoutIfNeeded()
}
return
}else if card.center.x < -115 {
delegate?.swipeDidEnd(on: card)
UIView.animate(withDuration: 0.2) {
card.center = CGPoint(x: centerOfParentContainer.x + point.x - 200, y: centerOfParentContainer.y + point.y + 75)
card.alpha = 0
self.layoutIfNeeded()
}
return
}
UIView.animate(withDuration: 0.2) {
card.transform = .identity
card.center = CGPoint(x: self.frame.width / 2, y: self.frame.height / 2)
self.layoutIfNeeded()
}
default:
break
}
}
In this subclass I have two UIViews, I am adding the views sequentially. Then on swipeView I am adding the text and label and background color. This is how the cards look like:
I am also using a UIPanInteraction on it and so if I drag it to left or right, then I call the delegate which removes the entire MainSwipeCardView from the container view. In doing so this is what happens:
It keeps adding more and more in the background even though this is what I am calling in the delegate function:
func swipeDidEnd(on card: MainSwipeCardView) {
card.removeFromSuperview()
print(visibleCards.count)
}
The visibleCards is essentially an array of subviews in the container view. It should decrease so for example from 3 -> 2 -> 1; but it increases in non linear way ( not able to really get a relationship out of it)
The most confusing thing is that I am actually able to run this whole code just fine if I donot add the SwipeView and shadowView properties inside the custom view and just use the customView itself to house the label and the backgroundColor. When I add these two properties, then this whole thing seem to go haywire.
Please any kind of help will be extremely appreciated. Thanks!
ContainerView code is as follows:
class SwipeCardContainerView: UIView, CardDelegate {
//MARK: - Properties
var numberOfCards: Int = 0
var remainingCards: Int = 0
var cardsView : [MainSwipeCardView] = []
var numberOfAllowedCard: Int = 3
let horizontalInset: CGFloat = 8.0
let verticalInset: CGFloat = 8.0
var visibleCards : [MainSwipeCardView] {
return subviews as? [MainSwipeCardView] ?? []
}
var datasource : CardDataSource? {
didSet {
loadData()
}
}
override init(frame: CGRect) {
super.init(frame: .zero)
backgroundColor = .clear
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
// MARK: - Configuration
func loadData() {
guard let datasource = datasource else { return }
numberOfCards = datasource.numberOfCards()
remainingCards = numberOfCards
for i in 0..<min(numberOfCards,numberOfAllowedCard) {
addCardView(at: i, card: datasource.createCard(at: i))
}
setNeedsLayout()
}
func addCardView(at index: Int, card: MainSwipeCardView) {
card.delegate = self
addCardFrame(index: index, cardView: card)
cardsView.append(card)
insertSubview(card, at: 0)
remainingCards -= 1
}
func addCardFrame(index: Int, cardView: MainSwipeCardView){
cardsView.append(cardView)
var cardViewFrame = bounds
let horizontalInset = (CGFloat(index) * self.horizontalInset)
let verticalInset = CGFloat(index) * self.verticalInset
cardViewFrame.size.width -= 2 * horizontalInset
cardViewFrame.origin.x += horizontalInset
cardViewFrame.origin.y += verticalInset
cardView.frame = cardViewFrame
}
// Delegate Method
func swipeDidEnd(on card: MainSwipeCardView) {
card.removeFromSuperview()
print(visibleCards.count)
}
Main ViewController Code:
class ViewController: UIViewController {
//MARK: - Properties
var stackContainer : SwipeCardContainerView!
var cardDataArray : [CardDataModel] = [CardDataModel(backgroundColor: .orange, title: "Hello"),
CardDataModel(backgroundColor: .red, title: "Red"),
CardDataModel(backgroundColor: .blue, title: "Blue"),
CardDataModel(backgroundColor: .orange, title: "Orange")]
//MARK: - Init
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(red:0.93, green:0.93, blue:0.93, alpha:1.0)
stackContainer = SwipeCardContainerView()
view.addSubview(stackContainer)
configureSwipeContainerView()
stackContainer.translatesAutoresizingMaskIntoConstraints = false
}
//MARK : - Configurations
func configureSwipeContainerView() {
stackContainer.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
stackContainer.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -50).isActive = true
stackContainer.widthAnchor.constraint(equalToConstant: 300).isActive = true
stackContainer.heightAnchor.constraint(equalToConstant: 350).isActive = true
}
override func viewDidLayoutSubviews() {
stackContainer.datasource = self
}
//MARK : - Handlers
}
extension ViewController : CardDataSource {
func numberOfCards() -> Int {
return cardDataArray.count
}
func createCard(at index: Int) -> MainSwipeCardView {
let card = MainSwipeCardView()
card.cardsarraydata = cardDataArray[index]
return card
}
func emptyCard() -> UIView? {
return nil
}
}

Answer 1

I've investigated the problem.
First issue is in the ViewController:
override func viewDidLayoutSubviews() {
stackContainer.datasource = self
}
Just remove this code. In each layout you set datasource... and loadData... this is incorrect approach, also super.viewDidLayoutSubviews() is missing...
And also stackContainer.datasource = self:
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(red:0.93, green:0.93, blue:0.93, alpha:1.0)
stackContainer = SwipeCardContainerView()
view.addSubview(stackContainer)
configureSwipeContainerView()
stackContainer.translatesAutoresizingMaskIntoConstraints = false
stackContainer.datasource = self
Second issue is in func loadData(), just replace it with
func loadData() {
guard let datasource = datasource else { return }
setNeedsLayout()
layoutIfNeeded()
numberOfCards = datasource.numberOfCards()
remainingCards = numberOfCards
for i in 0..<min(numberOfCards,numberOfAllowedCard) {
addCardView(at: i, card: datasource.createCard(at: i))
}
}
or find better solution with layout of SwipeCardContainerView