Ios 无法转换类型为'；NSRange'；（aka'；u NSRange'；）到预期类型'；范围<；指数>'；（aka'；Range<；String.CharacterView.Index>；'；）

检查字符串范围时出现此错误

@objc func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    let shouldChange = false
    let text = textField.text
    var newString = text!.stringByReplacingCharactersInRange(range, withString: string) as? NSString
    if newString.length > 14{
        newString = newString.substringToIndex(14)
    }
    textField.text = newString.uppercaseString

    return shouldChange
}

---

而不是

文本说
（文本！作为NSString）

Swift 4

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

    if let oldString = textField.text {
        let newString = oldString.replacingCharacters(in: Range(range, in: oldString)!,
                                                      with: string)
        // ...
    }
    // ...
}

比较一下。
func textField(_ textField: UITextField,
               shouldChangeCharactersIn range: NSRange,
               replacementString string: String) -> Bool {

    if let oldString = textField.text {
        let newString = oldString.replacingCharacters(in: Range(range, in: oldString)!,
                                                      with: string)
        // ...
    }
    // ...
}