Question

我正在设置MainViewController和PopUpViewController。

在MainVC中，我有一个滑块，它表示从 0到800 cm的高度。同样在这里，我有2个标签，分别用英尺+英寸和米+厘米来表示厘米的转换。

在HeightTableViewCell中，我拥有所有的插座和滑块，并且那里有一个与MainVC进行通信的代表。

在PopUpViewController中，我有一个保存按钮和3个UITextFields（厘米，英尺和英寸）。当我按下保存按钮时，我想在MainVC滑块中设置正确的值，并在标签中显示转换。

由于我无法访问UISlider中的UISlider，我该如何使用这些委托方法设置TableViewCell？

我已经尝试过将数据传递给委托人。还有其他更好的方法吗？

这是我的MainVC：

class MainViewController: UIViewController {

    var sliderValue: Float = 0.0    

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

extension MainViewController: UITableViewDelegate, UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "heightCell", for: indexPath) as! HeightTableViewCell
        cell.configVehicleHeightCell(sliderValue)
        cell.delegate = self

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        switch indexPath.row {
        case 0: return 150
        default:
            return 150
        }
    }
}

// Receive data from the Cell to MainVC
extension MainViewController: HeightCellDelegate {

    func heightSliderValueChanged(_ slider: UISlider, _ feetsLabel: UILabel, _ metersLabel: UILabel) {

        let currentValue = Int(slider.value)
        let meters = currentValue / 100
        let centimeters = currentValue % 100
        let inches = currentValue < 3 ? 0 : round(Double(currentValue) / 2.54)
        let feet = round(inches / 12)
        let inch = round(inches.truncatingRemainder(dividingBy: 12))

        feetsLabel.text = "\(feet) ft" + " \(inch)\""
        metersLabel.text = "\(meters) m" + " \(centimeters) cm"
    }
}

// Receive data (centimeters) from the PopUp to MainVC
extension MainViewController: HeightPopUpDelegate {

    func receiveHeightMetric(centimeters: Float?) {
        print("\n\nMetric Data received")
        print("Centimeters: \(centimeters ?? 0)")

        sliderValue = Float(centimeters ?? 0)
        tableView.reloadData()
    }

    func receiveHeightImperial(feet: Int?, inches: Int?) {

        print("\n\nImperial Data received")
        print("Feet: \(feet ?? 0)")
        print("Inches: \(inches ?? 0)")
    }

    // Receive the data from PopUpViewController
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == "goToHeight" {
            let vc: PopUpViewController = segue.destination as! PopUpViewController
            vc.delegate = self
        }
    }
}

这是我的MainVC单元：

protocol HeightCellDelegate {
    func heightSliderValueChanged(_ slider: UISlider, _ feetsLabel: UILabel, _ metersLabel: UILabel)
}

class HeightTableViewCell: UITableViewCell {

    // Interface Links
    @IBOutlet weak var heightLabelTitle: UILabel!
    @IBOutlet weak var heightSlider: UISlider!
    @IBOutlet weak var heightFeetsLabel: UILabel!
    @IBOutlet weak var heightMetersLabel: UILabel!

    // Properties
    var delegate: HeightCellDelegate?

    override func awakeFromNib() {
        super.awakeFromNib()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
    }

   func configVehicleHeightCell(_ value : Float){

    heightSlider.value = value
    heightLabelTitle.text = "Height"


    let meters  = Int((value) / 100)
    let centimeters  = Int(value.truncatingRemainder(dividingBy: 100))
    let inches = Int(value) < 3 ? 0 : round((value) / 2.54)
    let feet = Int(round(inches / 12))
    let inch = Int(round(inches.truncatingRemainder(dividingBy: 12)))

    heightFeetsLabel.text = "\(feet) ft" + " \(inch)\""
    heightMetersLabel.text = "\((meters)) m" + " \((centimeters)) cm"
}

    @IBAction func heightValueChanged(_ sender: UISlider) {

        configVehicleHeightCell(sender.value)
    }
}

这是我的PopUpVC代码：

protocol HeightPopUpDelegate {
    func receiveHeightMetric(centimeters: Int?)
    func receiveHeightImperial(feet: Int?, inches: Int?)
}

class PopUpViewController: UIViewController {

    // Interface Links
    @IBOutlet weak var centimetersTextField: UITextField!
    @IBOutlet weak var feetTextField: UITextField!
    @IBOutlet weak var inchesTextField: UITextField!
    @IBOutlet weak var labelForOr: UILabel!
    @IBOutlet weak var popUpView: UIView!
    @IBOutlet weak var cancelBtnOutlet: UIButton!
    @IBOutlet weak var saveBtnOutlet: UIButton!

    // Properties
    var delegate: HeightPopUpDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
        setupViews()
    }

    // Dismiss the popup when user press the Cancel btn
    @IBAction func cancelBtnTapped(_ sender: UIButton) {

        dismiss(animated: true, completion: nil)
    }

    // Save the data and send it back when user press the Save btn
    @IBAction func saveBtnTapped(_ sender: UIButton) {

        checkImperialOrMetricTextfields()
        dismiss(animated: true, completion: nil)
    }

    // Check if the textfields contains Metric or Imperial height. If everything is OK then send the data back.
    func checkImperialOrMetricTextfields(){

        if ((!(centimetersTextField.text?.isEmpty)!) && (!(feetTextField.text?.isEmpty)! || !(inchesTextField.text?.isEmpty)!)) {

            showAlertWithTitle(title: "Error", message: "Enter either metric OR imperial height.")
            clearTextFields()
        }
        if ((centimetersTextField.text?.isEmpty)! && (feetTextField.text?.isEmpty)! && (inchesTextField.text?.isEmpty)!) {

            showAlertWithTitle(title: "Error", message: "Enter either metric OR imperial height.")
            clearTextFields()
        }
        else{
            sendDataBack()
        }
    }

    // Clear textfields
    func clearTextFields(){

        centimetersTextField.text = ""
        feetTextField.text = ""
        inchesTextField.text = ""
    }

    // Function used to send data back from the PopUp to MainVC
    func sendDataBack(){

        if delegate != nil{
            delegate?.receiveHeightMetric(centimeters: Int(centimetersTextField?.text ?? "0"))
            delegate?.receiveHeightImperial(feet: Int(feetTextField?.text ?? "0"), inches: Int(inchesTextField?.text ?? "0"))
        }
    }

    // Setup the design for outlets
    func setupViews(){

        popUpView.layer.cornerRadius = 20
        popUpView.layer.masksToBounds = true

        cancelBtnOutlet.layer.cornerRadius = 5
        cancelBtnOutlet.layer.borderWidth = 0.5
        cancelBtnOutlet.layer.borderColor = UIColor.black.cgColor

        saveBtnOutlet.layer.cornerRadius = 5
        saveBtnOutlet.layer.borderWidth = 0.5
        saveBtnOutlet.layer.borderColor = UIColor.black.cgColor
    }

    // Function to hide the Popup when the user click anywhere on the screen
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        let touch = touches.first
        if touch?.view == self.view {
            dismiss(animated: true, completion: nil)
        }
    }

    // Show an alert view with Title
    func showAlertWithTitle(title: String = "", message: String) {
        let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let OKAction = UIAlertAction(title: "OK", style: .default, handler: nil)
        alertController.addAction(OKAction)
        self.present(alertController, animated: true, completion: nil)
    }
}

当我在PopUp中设置某些内容并单击“保存”时，会在控制台中从该文本字段获得值：

Metric Data received
Centimeters: 0

Imperial Data received
Feet: 23
Inches: 45

如果正在帮助任何人，以下是此小示例的链接： https://github.com/tygruletz/ImperialAndMetricMeasurement

非常感谢您阅读本文，希望我提供正确的详细信息。

Answer 1

我进行了一些更改，下面是cm/m的工作示例，

在HeightTableViewCell中，在此处设置标签和滑块。我将Int设置为Float的地方很少。

func configVehicleHeightCell(_ value : Float){
    heightSlider.value = value
    heightLabelTitle.text = "Height"


    let meters  = Int((value) / 100)
    let centimeters  = Int(value.truncatingRemainder(dividingBy: 100))
    let inches = Int(value) < 3 ? 0 : round((value) / 2.54)
    let feet = Int(round(inches / 12))
    let inch = Int(round(inches.truncatingRemainder(dividingBy: 12)))

    heightFeetsLabel.text = "\(feet) ft" + " \(inch)\""
    heightMetersLabel.text = "\((meters)) m" + " \((centimeters)) cm"
}

您不再需要委托，heightValueChanged

@IBAction func heightValueChanged(_ sender: UISlider) {

    configVehicleHeightCell((sender.value))
}

在MainVC中创建var sliderValue : Float = 0.0
在cellForRow中，cell.configVehicleHeightCell(sliderValue)

最后，当用户在警报中输入数据时（在cm文本字段中有效）

func receiveHeightMetric(centimeters: Float?) {
    print("\n\nMetric Data received")
    print("Centimeters: \(centimeters ?? 0)")

    sliderValue = centimeters ?? 0
    mtTableView.reloadData()
}

输出：

编辑

对于feet/inch，只需执行以下操作

func receiveHeightImperial(feet: Int?, inches: Int?){
   // 1. convert feet, inch into centimeter.    
   // 2. If either of feet/inch is nil then consider it as zero, for safety
   // 3. Now, sliderValue = new_cm_value (value that you calculated from feet/inch)
   // 4. Now reloadData().
}

Answer 2

您只有一个牢房，因此您可以：

MainVC

@IBOutlet weak var tableView: UITableView!

    func receiveHeightMetric(centimeters: Int?) {
        print("\n\nMetric Data received")
        print("Centimeters: \(centimeters ?? 0)")

        let cell = self.tableView.cellForRow(at: IndexPath(row: 0, section: 0)) as! HeightTableViewCell
        cell.refresh(centimeters: centimeters)
    }

    func receiveHeightImperial(feet: Int?, inches: Int?) {

        print("\n\nImperial Data received")
        print("Feet: \(feet ?? 0)")
        print("Inches: \(inches ?? 0)")


        let cell = self.tableView.cellForRow(at: IndexPath(row: 0, section: 0)) as! HeightTableViewCell
        cell.refresh(feet: feet, inches: inches)
    }

HeightTableViewCell

    func refresh(centimeters: Int?) {
        print("\n\nMetric Data received in cell")
        print("Centimeters: \(centimeters ?? 0)")
    }
    func refresh(feet: Int?, inches: Int?) {

        print("\n\nImperial Data received in cell")
        print("Feet: \(feet ?? 0)")
        print("Inches: \(inches ?? 0)")
    }

Answer 3

您可以为UIViewController创建一个协议，该协议将由UITableViewCell所遵循。

say-

protocol UpdateSlider : class {

    func updateSlider(with value : CGFloat)

}

现在您的MainViewController将具有该协议的变量，并且您将通过单元格的引用在cellForRowAt方法中为该变量分配一个值。

class MainViewController : UIViewController {

    weak var delegate : UpdateSlider?
}


func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "heightCell", for: indexPath) as! HeightTableViewCell
    cell.configVehicleHeightCell()
    cell.delegate = self
    self.delegate = cell
    return cell
}

无论何时要更新滑块的值，只需调用MainViewController的委托方法。

self.delegate?.updateSlider(with value : <#CustomValue#>)

P.S。 -您随时可以在cellForRowAt中设置当前值，并在需要时重新加载单元格。

如何使用UITableViewCell中的委托方法设置UISlider

3 个答案: