在 Xcode 中禁用/启用按钮

Question

嗨，我是 Swift 编程新手。我想做的是在 viewDidLoad 中禁用我的按钮（登录），并且仅在文本字段中包含文本时才启用。这是我到目前为止所取得的成就。（虽然不多！）

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    signIn.isEnabled = false

    // Do any additional setup after loading the view, typically from a nib.
}

@IBOutlet weak var emailtxt: UITextField!
@IBOutlet weak var passwordtxt: UITextField!
@IBOutlet weak var signIn: UIButton!

我需要帮助在 signIn 中创建一个功能，该功能使按钮保持禁用状态，直到文本字段（emailtxt 和 passwordtxt）中有文本，然后继续。

很高兴有人能帮我分类。提前致谢！

Answer 1

像这样将 ViewController 设置为 emailtxt 和 passwordtxt 的代表，

override func viewDidLoad() {
    super.viewDidLoad()
    signIn.isEnabled = false

    emailtxt.delegate = self
    passwordtxt.delegate = self 

    // Do any additional setup after loading the view, typically from a nib.
}

当文本输入完成时，将您的 ViewController 与 UITextFieldDelegate 和 enable/disable 一致，

extension ViewController: UITextFieldDelegate {

    func textFieldDidEndEditing(_ textField: UITextField) {
        if emailtxt.text?.isEmpty == false && passwordtxt.text?.isEmpty == false {
            signIn.isEnabled = true
        } else {
            signIn.isEnabled = false
        }
    }
}

这是您共享的代码的修复程序。

import UIKit
extension UIViewController {

    func hideKeyboardWhenTappedAround() {
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(UIViewController.dismissKeyboard))
        tap.cancelsTouchesInView = false
        view.addGestureRecognizer(tap)
    }

    @objc func dismissKeyboard() {
        view.endEditing(true)
    }
}

extension SignInVC: UITextFieldDelegate {

    func textFieldDidEndEditing(_ textField: UITextField) {
        if emailtxt.text?.isEmpty == false && passwordtxt.text?.isEmpty == false {
            signIn.isEnabled = true
        } else {
            signIn.isEnabled = false
        }
    }
}
class SignInVC: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        signIn.isEnabled = false
        emailtxt.delegate = self
        passwordtxt.delegate = self
        self.hideKeyboardWhenTappedAround()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    @IBOutlet weak var emailtxt: UITextField!
    @IBOutlet weak var passwordtxt: UITextField!
    @IBOutlet weak var signIn: UIButton!
}

Answer 2

使用SwiftValidator

https://github.com/SwiftValidatorCommunity/SwiftValidator

这样，您将像下面这样设置电子邮件和密码的验证

import SwiftValidator

let validator = Validator()

validator.registerField(emailTextField, errorLabel: emailErrorLabel, rules: [RequiredRule(), EmailRule(message: "Invalid email")])




// MARK: - ValidationDelegate
extension ViewController: ValidationDelegate {
    func validationSuccessful() {
        self.loginUser()
    }

    func validationFailed(_ errors:[(Validatable ,ValidationError)]) {
        for (field, error) in errors {

//Handle as per need - show extra label - shake view etc
/*
            if let field = field as? UITextField {
                Utilities.shakeTheView(shakeView: field)
            }
            error.errorLabel?.text = error.errorMessage
            error.errorLabel?.isHidden = false
*/
        }
    }
}

Answer 3

首先为 viewDidLoad() 中的所有文本字段添加这些：

    emailtxt.addTarget(self, action: #selector(textFieldDidChange(_:)),
                        for: UIControlEvents.editingChanged)
   passwordtxt.addTarget(self, action: #selector(textFieldDidChange(_:)),
                        for: UIControlEvents.editingChanged)

然后使用这个：

@objc func textFieldDidChange(_ textField: UITextField) {
    self.buttonIsEnabled()
}

func buttonIsEnabled() {
    var buttonIsEnabled = true

    defer {
        self.signIn.isEnabled = buttonIsEnabled
    }

    guard let emailtxt = self.emailtxt.text, !emailtxt.isEmpty  else {
        addButtonIsEnabled = false
        return
    }


    guard let passwordtxt = self. passwordtxt.text, ! passwordtxt.isEmpty  else {
        addButtonIsEnabled = false
        return
    }

}

我在我的代码中使用这种方式并且效果很好。

甚至您可以添加更多方法来对 buttonIsEnabled 进行额外检查，例如：

self.checkEmailIsValid(for: emailtxt)

当然你应该先处理这个方法：

 func checkEmailIsValid(for: String) {
   //...
}

Answer 4

我要做的是从您的一个文本字段创建一个 IBAction，并将事件设置为 Editing Changed:

代码应如下所示：

@IBAction func textFieldEditingDidChange(_ sender: UITextField) {

}

然后您可以通过从插座拖动到您的剩余字段，将同一个插座连接到您的两个文本字段。如果两者都正确连接，单击 IBAction 左侧的圆圈应该会显示两个文本字段：

现在，每当您的字段中的文本发生变化时，都会触发该操作。

然后，在文件的顶部，我将创建一个属性的计算结果 returns false 除非两个字段中都有内容：

var shouldEnableButton: Bool {
    guard let text1 = textField1.text, let text2 = textField2.text else {
        return false
    }
    return text1.isEmpty && text2.isEmpty ? false : true
}

最后，我们将 shouldEnableButton 添加到我们的 IBAction 中：

@IBAction func textFieldEditingDidChange(_ sender: UITextField) {
    button.isEnabled = shouldEnableButton
}

重要

当您将第二个文本字段连接到插座时，它会错误地将 Editing Did End 指定为其事件：

删除此事件并单击并从 Editing Changed 拖动到您的 IBAction：

在 Xcode 中禁用/启用按钮

Disable / Enable a button in Xcode

xcode

ios

swift

xcode8

swift4

重要