UITextfield 作为浮动通过 segue 传递到 UILabel

Question

我是 swift 的新手，希望用户使用 UITextfield 的小数位输入数字以输入浮点数，然后使用 UILabel 将该浮点数传递给另一个视图控制器。除了将浮点数传递给另一个视图控制器上的 UILabel 之外，一切正常。我得到这个错误

"Cannot assign value of type 'UITextField?' to type 'UILabel?'"

import UIKit

class SelectAttributesViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {

    @IBOutlet weak var kitPickerView: UIPickerView!
    @IBOutlet weak var reactionVolumeLabel: UILabel!
    @IBOutlet weak var numberOfSampleTextField: UITextField!
    @IBOutlet weak var volumeOfTemplateDNATextField: UITextField!
    @IBOutlet weak var slider: UISlider!
    @IBOutlet weak var calculateButton: UIButton!

    let kits = ["kit 1", "Kit 2"]
    let pArray = [10,20,50]

    override func viewDidLoad() {
        super.viewDidLoad()
        self.numberOfSampleTextField.delegate = self
        self.volumeOfTemplateDNATextField.delegate = self
        kitPickerView.dataSource = self
        kitPickerView.delegate = self



        let tap = UITapGestureRecognizer(target: self.view, action: #selector(UIView.endEditing(_:)))
        view.addGestureRecognizer(tap)


    }

    func pSliderInterval() {
        slider.minimumValue = 0
        slider.maximumValue = Float(pArray.count)
        slider.isContinuous = false

    }


    @IBAction func reactionVolumeSlider(_ sender: UISlider) {
        print(Int(sender.value))
        let currentValue = pArray[Int(sender.value)]
        reactionVolumeLabel.text = "\(currentValue) "


    }
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
       return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return kits.count

    }
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if row == 0{ print(kits[row])

        }else if row == 1{
           createAlert(title: "Kit not available", message: "More kits will be added soon!")
            calculateButton.isEnabled = false
        }

    }
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return kits[row]
    }
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
           guard let oldText = textField.text, let r = Range(range, in: oldText) else {
               return true
           }

           let newText = oldText.replacingCharacters(in: r, with: string)
           let isNumeric = newText.isEmpty || (Double(newText) != nil)
           let numberOfDots = newText.components(separatedBy: ".").count - 1

           let numberOfDecimalDigits: Int
           if let dotIndex = newText.firstIndex(of: ".") {
               numberOfDecimalDigits = newText.distance(from: dotIndex, to: newText.endIndex) - 1
           } else {
               numberOfDecimalDigits = 0
           }

           return isNumeric && numberOfDots <= 1 && numberOfDecimalDigits <= 2
       }
    func createAlert (title: String, message: String){
           let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertController.Style.alert)
           alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: { (Action) in
               alert.dismiss(animated: true, completion: nil)
           }))
           self.present(alert, animated: true, completion: nil)

       }
    // This is the Segue.
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        var masterMix = segue.destination as! MasterMixTableViewController

        masterMix.waterVolumeLabel = numberOfSampleTextField
    }

    @IBAction func calculatePressed(_ sender: Any) {
        if numberOfSampleTextField.text != ""{
            performSegue(withIdentifier: "masterMixSegue", sender: self)
        }

    }




}

我浏览了大量的解决方案，但没有找到任何东西。

Answer 1

你需要

let masterMix = segue.destination as! MasterMixTableViewController
masterMix.loadViewIfNeeded()
masterMix.waterVolumeLabel!.text = numberOfSampleTextField!.text

Answer 2

错误提示您正在将 UITextField 分配给 UILabel。但是你必须将 textFeild.text 分配给 label.text.

let textField = UITextField()
let label = UILabel()
label.text = textField.text

UITextfield 作为浮动通过 segue 传递到 UILabel

UITextfield as float passed through segue to an UILabel

ios

swift

segue