Swift CollectionView is selecting multiple cell when is set to false

Question

Im currently have a horizontal collection view. I currently have multiple selection enabled set to off. For some reason when I select the first item the item toward the end of the collectionView also become selected. Thank you for the hep.

 protocol customDatePickerDelegate:class {
    func dateFromCustomDatePicker(date:Date)
}
class datePickerCollectionViewCell:UICollectionViewCell {
    var labelNumber:UILabel = UILabel()
    var minuteLabel:UILabel = {
        let v = UILabel()
        v.text = "Minutes"
        return v
    }()


    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = .white
        minuteLabel.labelFormCustom(labelType: .dateForm)

        labelNumber.translatesAutoresizingMaskIntoConstraints = false
        self.addSubview(labelNumber)
        labelNumber.centerYAnchor.constraint(equalTo: self.centerYAnchor, constant: 0).isActive = true
        labelNumber.centerXAnchor.constraint(equalTo: self.centerXAnchor, constant: 0).isActive = true

        minuteLabel.translatesAutoresizingMaskIntoConstraints = false
        self.addSubview(minuteLabel)
        minuteLabel.centerXAnchor.constraint(equalTo: self.centerXAnchor, constant: 0).isActive = true
        minuteLabel.topAnchor.constraint(equalTo: labelNumber.bottomAnchor, constant: 0).isActive = true

        self.layer.cornerRadius = 6
        self.layer.borderWidth = 0.5
        self.layer.borderColor = UIColor(red:205.0/255.0, green:205.0/255.0, blue:205.0/255.0, alpha: 1.0).cgColor

    }

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

class NewRquestDatePickerCollectionViewController: UIViewController,UICollectionViewDelegate {
    var collectionView:UICollectionView!
    override func viewDidLoad() {
         setupCollectionView()
    }
    lazy var centerView:UIView = {
        let v = UIView()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.heightAnchor.constraint(equalToConstant: 300).isActive = true
        v.backgroundColor = .white
        v.addBorderCustom(.bottom)

        return v
    }()
    lazy var durationLabel:UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.textAlignment = .center
        v.font = v.font.withSize(17)

        return v
    }()
    lazy var topActionBar:UIView = {
        let v = UIView()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.heightAnchor.constraint(equalToConstant: 60).isActive = true
        v.backgroundColor = UIColor(hex: "F9F9F9")
        v.addBorderCustom(.top)
        v.addBorderCustom(.bottom)

        return v
    }()
    lazy var doneButton:UIButton! = {
        let v = UIButton(type:.system)
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Done", for: .normal)
        v.addTarget(self, action: #selector(doneButtonPressed), for: .touchUpInside)

        return v
    }()
    lazy var cancelButton:UIButton = {
        let v = UIButton(type:.system)
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Cancel", for: .normal)
        v.addTarget(self, action: #selector(dismissCurrentView), for: .touchUpInside)

        return v
    }()
    lazy var dayLabel:UILabel = {
        let v = UILabel()
//        v.text = "Monday"
        return v
    }()
    lazy var titleView:UILabel = {
        let v = UILabel()
        v.text = "Select a deadline"
        v.translatesAutoresizingMaskIntoConstraints = false

        return v
    }()

    var selectedIndexPath: NSIndexPath?

//    var selectedTime:Int!
    var timer = Timer()
    var timeSeleted:TimeInterval = 10.0
    let timeArray:[TimeInterval] = [10,20,30,45,60,140,400,900,1200]
    var delegate:customDatePickerDelegate!
    var dateSelected:Date!

    func setupCollectionView(){
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal

        //collection view setup
        self.view.addSubview(centerView)
        centerView.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: 0).isActive = true
        centerView.rightAnchor.constraint(equalTo: self.view.rightAnchor, constant: 0).isActive = true
        centerView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
        collectionView = UICollectionView(frame: view.frame, collectionViewLayout: layout)
        collectionView.register(datePickerCollectionViewCell.self, forCellWithReuseIdentifier: "imageCell")
        collectionView.delegate = self
        collectionView.dataSource = self

        centerView.addSubview(topActionBar)
        topActionBar.heightAnchor.constraint(equalToConstant: 49).isActive = true
        topActionBar.leftAnchor.constraint(equalTo: self.centerView.leftAnchor, constant: 0).isActive = true
        topActionBar.rightAnchor.constraint(equalTo: self.centerView.rightAnchor, constant: 0).isActive = true
        topActionBar.topAnchor.constraint(equalTo: self.centerView.topAnchor, constant: 0).isActive = true

        topActionBar.addSubview(cancelButton)
        topActionBar.addSubview(titleView)

        cancelButton.leftAnchor.constraint(equalTo: topActionBar.leftAnchor, constant: 16).isActive = true
        cancelButton.centerYAnchor.constraint(equalTo: topActionBar.centerYAnchor, constant: 0).isActive = true

        titleView.centerXAnchor.constraint(equalTo: topActionBar.centerXAnchor, constant: 0).isActive = true
        titleView.centerYAnchor.constraint(equalTo: topActionBar.centerYAnchor, constant: 0).isActive = true

        centerView.addSubview(doneButton)
        centerView.addBorderCustom(.bottom)
        doneButton.centerXAnchor.constraint(equalTo: centerView.centerXAnchor, constant: 0).isActive = true
        doneButton.bottomAnchor.constraint(equalTo: centerView.bottomAnchor, constant: -20).isActive = true

        centerView.addBorderCustom(.bottom)
        centerView.addSubview(collectionView)
        collectionView.heightAnchor.constraint(equalToConstant: 100).isActive = true
        collectionView.leftAnchor.constraint(equalTo: self.centerView.leftAnchor, constant: 0).isActive = true
        collectionView.rightAnchor.constraint(equalTo: self.centerView.rightAnchor, constant: 0).isActive = true
        collectionView.topAnchor.constraint(equalTo: self.topActionBar.bottomAnchor, constant: 0).isActive = true

        dayLabel.translatesAutoresizingMaskIntoConstraints = false
        centerView.addSubview(dayLabel)
        dayLabel.centerXAnchor.constraint(equalTo: collectionView.centerXAnchor, constant: 0).isActive = true
        dayLabel.topAnchor.constraint(equalTo: collectionView.bottomAnchor, constant: 20).isActive = true

        centerView.addSubview(durationLabel)
        durationLabel.leftAnchor.constraint(equalTo: self.centerView.leftAnchor, constant: 0).isActive = true
        durationLabel.rightAnchor.constraint(equalTo: self.centerView.rightAnchor, constant: 0).isActive = true
        durationLabel.topAnchor.constraint(equalTo: self.collectionView.bottomAnchor, constant: 0).isActive = true
        durationLabel.bottomAnchor.constraint(equalTo: self.doneButton.topAnchor, constant: 20).isActive = true

        timerStart()
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.showsVerticalScrollIndicator = false

        collectionView.contentInset = UIEdgeInsets(top: 0, left: 16, bottom: 0, right: 16)
        collectionView.isPagingEnabled = true

        collectionView.translatesAutoresizingMaskIntoConstraints = false
        collectionView.backgroundColor = UIColor(hex:"EFF3F4")
        centerView.addBorderCustom(.bottom)
        collectionView.allowsMultipleSelection = false
    }
}

extension NewRquestDatePickerCollectionViewController {
    func dismissCurrentView(){
        self.dismiss(animated: true , completion: nil)

    }
    func doneButtonPressed(){
        delegate.dateFromCustomDatePicker(date: dateSelected)
        dismissCurrentView()
    }
    func tappedDeadlineSelection(){
    }
    func timerStart(){
        if #available(iOS 10.0, *) {
            timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true, block: { (timer) in
                let date = Date()
                let adjustedDate = date.addingTimeInterval(self.timeSeleted * 60.0)
                self.dateSelected = adjustedDate
                self.durationLabel.text = String(describing: adjustedDate.string(withFormat: "MM/dd/yy, h:mm a"))
                self.dayLabel.text = String(describing: adjustedDate.string(withFormat: "EEEE"))
            })
        } else {
            // Fallback on earlier versions
        }
    }
}

extension NewRquestDatePickerCollectionViewController:UICollectionViewDataSource,UICollectionViewDelegateFlowLayout {

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return timeArray.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "imageCell", for: indexPath) as! datePickerCollectionViewCell
        cell.awakeFromNib()
        return cell
    }
    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        let cellInfo = cell as! datePickerCollectionViewCell
        //converTime
        cellInfo.labelNumber.text = String(self.timeArray[indexPath.row])
    }
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! datePickerCollectionViewCell
        let timeAdded = self.timeArray[indexPath.row]
        cell.backgroundColor = UIColor(hex: "F2784B")
//        let timeAdded = self.timeArray[indexPath.row]
        cell.labelNumber.textColor = .white
        cell.minuteLabel.textColor = .white
        cell.layer.borderColor = UIColor.white.cgColor
        timeSeleted = timeAdded
        collectionView.selectItem(at: indexPath, animated: true, scrollPosition: .centeredHorizontally)

    }
    func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath) as! datePickerCollectionViewCell
        cell.backgroundColor = .white
        cell.labelNumber.textColor = .black
        cell.minuteLabel.textColor = UIColor().RquestCustomColors(.fontGray)

//        collectionView.performBatchUpdates(nil, completion: nil)
    }
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: 64, height: 64)

    }
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 30.0
    }
    func collectionView(_ collectionView: UICollectionView, layout
        collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 30.0
    }
}

Answer 1

You should make use of the "isSelected" method for the collection view cell. This way you will not have not save any selected indexpath.

So I recommend using this method:

Firstly,

        collectionView.allowsMultipleSelection = false

on the UICollectionViewCell you can override the isSelected method

didSet {
            if isSelected {
                 // Change UI for selected state
                radioButton.setImage(#imageLiteral(resourceName: "greenTick"), for: .normal)
            } else {
                // Chage UI for unselected state
                radioButton.setImage(#imageLiteral(resourceName: "radioInactive"), for: .normal)
            }
        }

Finally when you need to find out the indexpath for the selected item.

            guard let selectedIndex = self.collectionView.indexPathsForSelectedItems?.first else { return }

Answer 2

Because you are reusing existed cell, you should keep track selected item index and update cell state as below:

var selectedIndex: IndexPath?

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = collectionView.cellForItem(at: indexPath) as! datePickerCollectionViewCell
    let timeAdded = self.timeArray[indexPath.row]
    cell.backgroundColor = UIColor(hex: "F2784B")
//        let timeAdded = self.timeArray[indexPath.row]
    cell.labelNumber.textColor = .white
    cell.minuteLabel.textColor = .white
    cell.layer.borderColor = UIColor.white.cgColor
    timeSeleted = timeAdded
    collectionView.selectItem(at: indexPath, animated: true, scrollPosition: .centeredHorizontally)

    // add the following codes
    let lastSelectedIndex = self.selectedIndex
    self.selectedIndex = indexPath

    // unselect last selected index
    collectionView.reloadItems(at: [lastSelectedIndex!])

    // reload new selected index
    collectionView.reloadItems(at: [self.selectedIndex!])
}

func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    let cellInfo = cell as! datePickerCollectionViewCell
    //converTime
    cellInfo.labelNumber.text = String(self.timeArray[indexPath.row])

    // add this line of code
    cell.isSelected = (self.selectedIndex == indexPath)
}