我对 swift 相当陌生，希望用户使用 UITextfield 的小数点输入数字来输入 float ，然后使用 UILabel 将该 float 传递到另一个 View Controller 。除了将 float 传递给另一个 View Controller 上的 UILabel 之外，一切正常。我收到此错误
"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)
}
}
}
我已经大量浏览了解决方案，但没有找到任何东西。
最佳答案
你需要
let masterMix = segue.destination as! MasterMixTableViewController
masterMix.loadViewIfNeeded()
masterMix.waterVolumeLabel!.text = numberOfSampleTextField!.text
关于ios - UITextfield 作为 float 通过 segue 传递到 UILabel，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/59594503/