UIPickerView value inside of UITableView(based on DateCell) change detailLabel

Question

I tried to make my PickerView value to show on my UITableView detail Label. So I set in my FormCell.swift

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
  self.detailLabel.text = "\(component)\(row)"
}

It works however, when I click next cell, my detailLabel misses previous value like this.(my default label is "01min 30sec")

Any ideas about this problem? Here is my code about this problem.

// FormCell.swift
import UIKit

class FormCell: UITableViewCell, UIPickerViewDelegate, UIPickerViewDataSource {

    // outlet
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var detailLabel: UILabel!
    @IBOutlet weak var pickerView: UIPickerView!

    // variable
    var isObserving = false
    let minutes = Array(0...59)

    // initialize pickerView delegate, dataSource
    override func awakeFromNib() {
        super.awakeFromNib()
        self.pickerView.delegate = self
        self.pickerView.dataSource = self

    }

    // tableViewCell's height setup
    class var expandedHeight: CGFloat { get { return 200 } }
    class var defaultheight: CGFloat { get { return 44 } }

    func checkHeight() {
        pickerView.isHidden = (frame.height < FormCell.expandedHeight)
    }


    // for pickerView
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 2
    }
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return minutes.count
    }
    func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {

        let pickerLabel = UILabel()
        var titleData = ""
        titleData = "\(minutes[row])"
        pickerLabel.text = titleData
        return pickerLabel
    }
    func pickerView(_ pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
        return pickerView.frame.width / 3
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        self.detailLabel.text = "\(component)\(row)"
    }




    // set observer for expanding
    func watchFrameChanges() {
        if !isObserving {
            addObserver(self, forKeyPath: "frame", options: [NSKeyValueObservingOptions.new, NSKeyValueObservingOptions.initial], context: nil)
            isObserving = true;
        }
    }
    func ignoreFrameChanges() {
        if isObserving {
            removeObserver(self, forKeyPath: "frame")
            isObserving = false;
        }
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        if keyPath == "frame" {
            checkHeight()
        }
    }

}

my Controller

// AddCircuitVC.swift
import UIKit

class AddCircuitVC: UITableViewController {

    let formCellID = "formCell"
    var selectedIndexPath: IndexPath?


    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 9
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let itemData = dataArray[indexPath.row]
        var cellID = wordCellID

            cellID = formCellID
            let cell = tableView.dequeueReusableCell(withIdentifier: cellID) as? FormCell
            cell?.titleLabel.text = itemData[titleKey]

            return cell!


    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let previousIndexPath = selectedIndexPath

        if indexPath == selectedIndexPath {
            selectedIndexPath = nil
        } else {
            selectedIndexPath = indexPath
        }

        var indexPaths: Array<IndexPath> = []
        if let previous = previousIndexPath {
            indexPaths += [previous]
        }
        if let current = selectedIndexPath {
            indexPaths += [current]
        }

        if indexPaths.count > 0 {
            tableView.reloadRows(at: indexPaths, with: UITableViewRowAnimation.automatic)
        }

    }

    // observer
    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
            (cell as! FormCell).watchFrameChanges()
    }
    override func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) {
            (cell as! FormCell).ignoreFrameChanges()
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        for cell in tableView.visibleCells {
            if cell.isKind(of: FormCell.self) {
                (cell  as! FormCell).ignoreFrameChanges()
            }
        }
    }

    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
            if indexPath == selectedIndexPath {
                return FormCell.expandedHeight
            } else {
                return FormCell.defaultheight
            }
    }
}

Answer 1

You're only setting your table cell's self.detailLabel.text in your pickerView delegate method.

So when you scroll your cell off screen and then on-screen again, the table view cell "forgets" what it was set to before.

You need to modify your cellForRowAt indexPath: table view data source method to return a value for cell.detailLabel.text, and that means your ultimate data source -- the itemData dictionary in your dataArray -- needs to have a new entry for duration set by the picker.

I'd recommend passing along the itemData dictionary as a property or parameter when the customTableViewCell is created in cellForRowAt indexPath:, and when the user selects a duration, set the dictionary entry and make sure it gets saved / updated in your dataArray.