Swift:按钮启用不起作用？

Question

我有一个按钮在我的 View Controller 中被禁用。当编辑两个文本字段时，我有 IBActions。当两个文本字段都包含整数时，我试图启用该按钮。我曾尝试这样做，但每当我运行 ios 模拟器时，即使我将整数放入每个文本字段，该按钮也会保持禁用状态。为什么它一直处于禁用状态？我是 swift 的新手，所以请帮助我。这是我整个项目的代码:

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {

@IBOutlet weak var calculatorButton: UIButton!
@IBOutlet weak var inspirationLabel: UILabel!
@IBOutlet weak var beginningLabel: UILabel!
@IBOutlet weak var calculatorContainer: UIView!
@IBOutlet weak var answer1Label: UILabel!
@IBOutlet weak var doneButton: UIButton!
@IBOutlet weak var yourWeightTextField: UITextField!
@IBOutlet weak var calorieNumberTextField: UITextField!
@IBOutlet weak var menuExampleButton: UIButton!
@IBOutlet weak var aboutButton: UIButton!
@IBOutlet weak var calculateButton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib
    yourWeightTextField.delegate = self
    calorieNumberTextField.delegate = self
    calculateButton.enabled = false
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func calculatorButtonTapped(sender: AnyObject) {
    calculatorContainer.hidden = false
    inspirationLabel.hidden = true
    beginningLabel.hidden = true
    menuExampleButton.hidden = true
    aboutButton.hidden = true
}

@IBAction func yourWeightEditingDidEnd(sender: AnyObject) {
    yourWeightTextField.resignFirstResponder()
}

@IBAction func calorieNumberEditingDidEnd(sender: AnyObject) {
    calorieNumberTextField.resignFirstResponder()
}

var yourWeightFilled = false
var calorieNumberFilled = false

func yourWeightTextFieldValueValidInt(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    // Find out what the text field will be after adding the current edit
    let text = (yourWeightTextField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)

    if let intVal = text.toInt() {
        self.yourWeightFilled = true
    } else {
        self.yourWeightFilled = false
    }
    return true
}
func calorieNumberTextFieldValueValidInt(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    // Find out what the text field will be after adding the current edit
    let text = (calorieNumberTextField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)

    if let intVal = text.toInt() {
        self.calorieNumberFilled = true
    } else {
        self.calorieNumberFilled = false
    }
    return true
}

@IBAction func yourWeightTextFieldEdited(sender: AnyObject) {
    if self.yourWeightFilled && self.calorieNumberFilled {
        self.calculateButton.enabled = true
    }
}

@IBAction func calorieNumberTextFieldEdited(sender: AnyObject) {
    if self.yourWeightFilled && self.calorieNumberFilled {
        self.calculateButton.enabled = true
    }
}

Answer 1

您的委托(delegate)方法有点困惑——它们必须完全按照调用者的期望命名，否则将找不到它们，因此 yourWeightTextFieldValueValidInt() 和 calorieNumberTextFieldValueValidInt() 根本没有被调用。相反，您需要在一个方法中处理对两个 文本字段的编辑:

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    // Find out what the text field will be after adding the current edit
    let text = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)

    if textField == yourWeightTextField {
        yourWeightFilled = text.toInt() != nil
    } else if textField == calorieNumberTextField {
        calorieNumberFilled = text.toInt() != nil
    }

    return true
}