我试图检查当一个文本字段发生变化时,等效于textView - textViewDidChange的函数,到目前为止我已经做到了这一点:

  func textFieldDidBeginEditing(textField: UITextField) {
        if self.status.text == "" && self.username.text == "" {
            self.topRightButton.enabled = false
        } else {   
            self.topRightButton.enabled = true
        }
    }

哪种类型的工作,但topRightButton一经文本字段被按下就被启用,我想它只在文本实际输入时才被启用?


当前回答

txf_Subject.addTarget(self, action:#selector(didChangeFirstText), for: .editingChanged)

@objc func didChangeText(textField:UITextField) {
    let str = textField.text
    if(str?.contains(" "))!{
        let newstr = str?.replacingOccurrences(of: " ", with: "")
        textField.text = newstr
    }
}

@objc func didChangeFirstText(textField:UITextField) {
    if(textField.text == " "){
        textField.text = ""
    }
}

其他回答

textField(_:shouldChangeCharactersIn:replacementString:)在Xcode 8中为我工作,Swift 3如果你想检查每一个按键。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    // Whatever code you want to run here.
    // Keep in mind that the textfield hasn't yet been updated,
    // so use 'string' instead of 'textField.text' if you want to
    // access the string the textfield will have after a user presses a key

    var statusText = self.status.text
    var usernameText = self.username.text

    switch textField{
    case self.status:
        statusText = string
    case self.username:
        usernameText = string
    default:
        break
    }

    if statusText == "" && usernameText == "" {
        self.topRightButton.enabled = false
    } else {   
        self.topRightButton.enabled = true
    }

    //Return false if you don't want the textfield to be updated
    return true
}

斯威夫特4

textField.addTarget(self, action: #selector(textIsChanging), for: UIControlEvents.editingChanged)

@objc func textIsChanging(_ textField:UITextField) {

 print ("TextField is changing")

}

如果你想在用户完全输入后进行更改(一旦用户退出键盘或按enter键,它将被调用)。

textField.addTarget(self, action: #selector(textDidChange), for: UIControlEvents.editingDidEnd)

 @objc func textDidChange(_ textField:UITextField) {

       print ("TextField did changed") 
 }

如果不可能将addTarget绑定到你的UITextField,我建议你像上面建议的那样绑定其中一个,并在shouldChangeCharactersIn方法的末尾插入执行代码。

nameTextField.addTarget(self, action: #selector(RegistrationViewController.textFieldDidChange(_:)), for: .editingChanged)

@objc func textFieldDidChange(_ textField: UITextField) {
    if phoneNumberTextField.text!.count == 17 && nameTextField.text!.count > 0 {
        continueButtonOutlet.backgroundColor = UIColor(.green)
    } else {
        continueButtonOutlet.backgroundColor = .systemGray
    }
}

在调用中shouldChangeCharactersIn func。

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {

    guard let text = textField.text else {
        return true
    }
    let lastText = (text as NSString).replacingCharacters(in: range, with: string) as String

    if phoneNumberTextField == textField {
        textField.text = lastText.format("+7(NNN)-NNN-NN-NN", oldString: text)
        textFieldDidChange(phoneNumberTextField)
        return false
    }
    return true
}

您可以在接口生成器中建立此连接。

在故事板中,单击屏幕顶部的助理编辑器(中间的两个圆圈)。 在界面构建器中按Ctrl +单击文本字段。 从EditingChanged拖动到助手视图中的视图控制器类内部。 为函数命名(例如“textDidChange”),然后单击连接。

现在在iOS13+上有一个UITextField委托方法可用

optional func textFieldDidChangeSelection(_ textField: UITextField)