Question

我在一个UITextFields中有4个UIView，如下所示：

每个UITextField限制为4个字符。我希望实现UITextFields之间的自动切换，每个UITextField的计数字符。

我使用shouldChangeCharactersIn作为限制字符：

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let maxLength = 4
        var newString = String()
        let currentString: NSString = textField.text! as NSString
        newString = currentString.replacingCharacters(in: range, with: string)

        return newString.length <= maxLength
    }

这是我的切换工具：

func textFieldDidChange(_ textField: UITextField){

    let text = textField.text

    if text?.utf16.count == 4 {
        switch textField {
        case firstPartTextField:
            secondPartTextField.becomeFirstResponder()
        case secondPartTextField:
            thirdPartTextField.becomeFirstResponder()
        case thirdPartTextField:
            fourthPartTextField.becomeFirstResponder()
        default:
            break
        }
    }
}

我的问题是在删除文本时切换到上一个UITextField，当UITextField为空时我无法检测到backSpace事件。

Answer 1

在viewDidLoad（）

中添加textField的目标

firstTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    secTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    thirdTxt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)
    fourTXt.addTarget(self, action: #selector(textFieldDidChange(textField:)), for: UIControlEvents.editingChanged)

比创建选择器方法

func textFieldDidChange（textField：UITextField）{

    let text = textField.text

    if text?.utf16.count == 1{
        switch textField{
        case firstTxt:
            secTxt.becomeFirstResponder()
        case secTxt:
            thirdTxt.becomeFirstResponder()
        case thirdTxt:
            fourTXt.becomeFirstResponder()
        case fourTXt:
            fourTXt.resignFirstResponder()
        default:
            break
        }
    }else{

    }
}

Answer 2

制作所有文本字段的出口集合，并按如下方式对其进行配置：

OutletCollection：

{
    "error": {
        "code": "CP_SI_ValidationFailed",
        "message": "email and password is required"
    }
}

在viewDidLoad中添加：

@IBOutlet var textfields: [UITextField]!

在目标函数中，您将以这种方式限制计数：

for (i, tf) in textfields.enumerated() {
    tf.layer.cornerRadius = 5
    tf.clipsToBounds = true
    tf.tag = i
    tf.delegate = self
}

这将改变您的一个委托方法：

func textFieldDidChange(textField: UITextField) {
       let text = textField.text!
       if text.utf16.count >= 4 {
           if textField.tag < 4 {
               codeTextfields[textField.tag + 1].becomeFirstResponder()
           }
           else {
               textField.resignFirstResponder()
           }
       }
}

以下答案的精炼版：How to move cursor from one text field to another automatically in swift ios programmatically?

使用Swift在UITextFields之间自动切换

2 个答案: