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
我发现最干净的swift2唯一的解决方案是在NSRange上创建一个类别:
extension NSRange {
func stringRangeForText(string: String) -> Range<String.Index> {
let start = string.startIndex.advancedBy(self.location)
let end = start.advancedBy(self.length)
return Range<String.Index>(start: start, end: end)
}
}
然后调用它from for textfield delegate函数:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let range = range.stringRangeForText(textField.text)
let output = textField.text.stringByReplacingCharactersInRange(range, withString: string)
// your code goes here....
return true
}
其他回答
这与Emilie的回答相似，但是，因为你特别问如何将NSRange转换为Range<String。索引>，你会这样做:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let start = advance(textField.text.startIndex, range.location)
let end = advance(start, range.length)
let swiftRange = Range<String.Index>(start: start, end: end)
...
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let strString = ((textField.text)! as NSString).stringByReplacingCharactersInRange(range, withString: string)
}
extension StringProtocol where Index == String.Index {
func nsRange(of string: String) -> NSRange? {
guard let range = self.range(of: string) else { return nil }
return NSRange(range, in: self)
}
}
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)
我发现最干净的swift2唯一的解决方案是在NSRange上创建一个类别:
extension NSRange {
func stringRangeForText(string: String) -> Range<String.Index> {
let start = string.startIndex.advancedBy(self.location)
let end = start.advancedBy(self.length)
return Range<String.Index>(start: start, end: end)
}
}
然后调用它from for textfield delegate函数:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let range = range.stringRangeForText(textField.text)
let output = textField.text.stringByReplacingCharactersInRange(range, withString: string)
// your code goes here....
return true
}
