ios - swift : Value Changing Control Events Not Calling?

Question

因此，我已将目标添加到我创建的 IBAction 中，这些目标会在文本字段的值更改时发生。当这些 Action 发生时，系统应该检查两个文本字段是否都是整数。我将两个变量设置为 false，当它们都是 int 时，它们被设置为 true。在 IBAction 中，如果两个变量都包含整数，我有 if 语句告诉按钮启用。当我运行模拟器时，如果两个文本字段都包含整数，则此按钮不会启用。

我是 swift 的新手，所以如果可能的话，请写出所有代码以及它应该在我的代码中的什么位置。这是我目前所拥有的:

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
    // Calling the textfield valueChanged Methods
    yourWeightTextField.addTarget(self, action:"yourWeightValueChanged:", forControlEvents:.ValueChanged);
    calorieNumberTextField.addTarget(self, action:"calorieNumberValueChanged:", forControlEvents:.ValueChanged);
}

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
}

var yourWeightFilled = false
var calorieNumberFilled = false

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 the textfields have the properties of the function
    if textField == yourWeightTextField {
        yourWeightFilled = text.toInt() != nil
    } else if textField == calorieNumberTextField {
        calorieNumberFilled = text.toInt() != nil
    }

    return true
}

func textFieldShouldReturn(textField: UITextField) -> Bool
{
    textField.resignFirstResponder();
    return true;
}

// The methods to close the keyboard when editing is finished
@IBAction func yourWeightEditingDidEnd(sender: AnyObject) {
    yourWeightTextField.resignFirstResponder()
}

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

@IBAction func yourWeightValueChanged(sender: AnyObject) {
    // If both variables are true and the text fields contain integers, enable button
    if self.yourWeightFilled && self.calorieNumberFilled {
        self.calculateButton.enabled = true
    }
}
@IBAction func calorieNumberValueChanged(sender: AnyObject) {
    // If both variables are true and the text fields contain integers, enable button
    if self.yourWeightFilled && self.calorieNumberFilled {
        self.calculateButton.enabled = true
    }
}
}

Answer 1

您应该寻找 EditingChaged 事件，而不是 ValueChanged

编辑:我的意思是改变自:

yourWeightTextField.addTarget(self, action:"yourWeightValueChanged:", forControlEvents:.ValueChanged);
calorieNumberTextField.addTarget(self, action:"calorieNumberValueChanged:", forControlEvents:.ValueChanged);

到:

yourWeightTextField.addTarget(self, action:"yourWeightValueChanged:", forControlEvents:.EditingChanged);
calorieNumberTextField.addTarget(self, action:"calorieNumberValueChanged:", forControlEvents:.EditingChanged);

您只是在寻找错误的事件。