如何檢查UITextField是否再次變為空？

我正在創建一個簡單的 VC 日志。讓我們忽略用戶名和密碼的輸入驗證。我只想在用戶名和密碼的 UITextField 都不為空時啟用 UIButton。每當其中任何一個變為空時，我都希望禁用該按鈕。

 @IBAction func typingUserName(_ sender: Any) {
    usernameTxtfield.layer.shadowPath = UIBezierPath(rect: usernameTxtfield.bounds).cgPath
    usernameTxtfield.layer.shadowRadius = 2
    usernameTxtfield.layer.shadowOffset = .zero
    usernameTxtfield.layer.shadowOpacity = 0.5
    
    signInIcon.isEnabled = false
}

@IBAction func typingPassword(_ sender: Any) {
    passwordTxtfield.layer.shadowPath = UIBezierPath(rect: passwordTxtfield.bounds).cgPath
    passwordTxtfield.layer.shadowRadius = 2
    passwordTxtfield.layer.shadowOffset = .zero
    passwordTxtfield.layer.shadowOpacity = 0.5
    
    signInIcon.isEnabled = false
}

@IBAction func usernameTxtFieldEditingChnged(_ sender: Any) {
    usernameTxtfield.layer.shadowRadius = 0
    usernameTxtfield.layer.shadowOffset = .zero
    usernameTxtfield.layer.shadowOpacity = 0
    
    
}

@IBAction func passwordEditingChaned(_ sender: Any) {
    passwordTxtfield.layer.shadowRadius = 0
    passwordTxtfield.layer.shadowOffset = .zero
    passwordTxtfield.layer.shadowOpacity = 0
    
    signInIcon.isEnabled = true
}

@IBAction func signInClicked(_ sender: Any) {
    performSegue(withIdentifier: "welcomeVC", sender: signInIcon)
}

如您所見，我僅在密碼文本欄位 EditingChanged 被觸發后才啟用該按鈕。

uj5u.com熱心網友回復：

你可以觀察事件.editingChanged。

passwordTxtfield.addTarget(self, action: #selector(passwordEditingChaned), for: .editingChanged)
usernameTxtfield.addTarget(self, action: #selector(usernameTxtFieldEditingChnged), for: .editingChanged)

然后在這兩種方法中添加檢查：

signInIcon.isEnabled = passwordTxtfield.text?.isEmpty == false && usernameTxtfield.text?.isEmpty == false

uj5u.com熱心網友回復：

你必須實作這樣的東西：

if usernameTxtfield.text != "" && passwordTxtfield.text != "" {
    signInIcon.isEnabled = true
} else {
    signInIcon.isEnabled = false
}

您在每個 UITextField 的操作中添加這段代碼，您就可以開始了

uj5u.com熱心網友回復：

將textFields和Button的出口連接到 ViewController 類。

@IBOutlet private weak var usernameTxtfield: UITextField!
@IBOutlet private weak var passwordTxtfield: UITextField!

@IBOutlet private weak var signInButton: UIButton!

然后撰寫您的設定功能

private func setupTextFields() {
    // write your TextFields custom setup ...
    // also add delegate lines
    
    usernameTxtfield.delegate = self
    passwordTxtfield.delegate = self
}

你的 setupTextFields 函式來查看VC 的viewDidLoad并設定你的按鈕 isEnable = false

override func viewDidLoad() {
    super.viewDidLoad()

    setupTextFileds()

    setSignInButton(isEnable: false)
}

并撰寫 func 來獲取 textFields。

private func getTextFields() -> [UITextField] {
    return [usernameTxtfield, passwordTxtfield]
}

我們還需要檢查這些是否有效。

private func isInputsValid() -> Bool {
    var isValid: Bool = true
    
    let inputs: [UITextField] = getTextFields()
    
    if let input = inputs.first(where: { $0.text?.count == 0 }) {
        debugPrint("\(input) is not valid.")
        isValid = false
    }
    
    return isValid
}

還添加 func 來設定 Button

private func setSignInButton(isEnable: Bool) {
    signInButton.isEnabled = isEnable
}

然后撰寫 TextField委托函式以了解輸入正在更改并更改按鈕的條件。

extension ViewController: UITextFieldDelegate {

    func textFieldDidChangeSelection(_ textField: UITextField) {
        setSignInButton(isEnable: isInputsValid())
    }
}

我希望它有幫助:)

標籤：IOS迅速uikit

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