如何将NSRange转换为Range<String。索引>在Swift?

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)


当前回答

你需要使用Range<String。索引>而不是经典的NSRange。我这样做的方式(也许有一个更好的方式)是通过获取字符串的字符串。索引移动它与前进。

我不知道你要替换的范围是什么,但让我们假设你想替换前两个字符。

var start = textField.text.startIndex // Start at the string's start index
var end = advance(textField.text.startIndex, 2) // Take start index and advance 2 characters forward
var range: Range<String.Index> = Range<String.Index>(start: start,end: end)

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

其他回答

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    
    guard let current = textField.text, let r = Range(range, in: current) else {
        return false
    }
    
    let text = current.replacingCharacters(in: r, with: string)
    // ...
    return true
}

你需要使用Range<String。索引>而不是经典的NSRange。我这样做的方式(也许有一个更好的方式)是通过获取字符串的字符串。索引移动它与前进。

我不知道你要替换的范围是什么,但让我们假设你想替换前两个字符。

var start = textField.text.startIndex // Start at the string's start index
var end = advance(textField.text.startIndex, 2) // Take start index and advance 2 characters forward
var range: Range<String.Index> = Range<String.Index>(start: start,end: end)

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

NSString版本(相对于Swift String)的replacingCharacters(in: NSRange, with: NSString)接受NSRange,所以一个简单的解决方案是先将String转换为NSString。在Swift 3和2中,委托和替换方法的名称略有不同,所以这取决于你使用的Swift:

斯威夫特3.0

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)
}

快2.倍

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

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

在Swift 2.0中假设func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: string) -> Bool {:

var oldString = textfield.text!
let newRange = oldString.startIndex.advancedBy(range.location)..<oldString.startIndex.advancedBy(range.location + range.length)
let newString = oldString.stringByReplacingCharactersInRange(newRange, withString: string)
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

       let strString = ((textField.text)! as NSString).stringByReplacingCharactersInRange(range, withString: string)

 }