NSR范围

Question

如何在Swift中转换NSRange为Range<String.Index>？

我想使用以下UITextFieldDelegate方法：

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

textField.text.stringByReplacingCharactersInRange(???, withString: string)

Answer 1

的NSString版本（与Swift String相对）replacingCharacters(in: NSRange, with: NSString)接受an NSRange，因此一个简单的解决方案是将其 转换String为NSStringfirst。在Swift3和2中，委托和替换方法的名称略有不同，因此取决于您使用的是哪种Swift：

UITextField3.0

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

  let nsString = textField.text as NSString?
  let newString = nsString?.replacingCharacters(in: range, with: string)
}

UITextField2.x

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

    let nsString = textField.text as NSString?
    let newString = nsString?.stringByReplacingCharactersInRange(range, withString: string)
}