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
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)
其他回答
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)
}
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let strString = ((textField.text)! as NSString).stringByReplacingCharactersInRange(range, withString: string)
}
Swift 3.0 beta版官方文档在标题String下为这种情况提供了标准解决方案。UTF16View中的UTF16View元素匹配NSString字符标题
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)
Martin R的回答似乎是正确的，因为它代表了Unicode。
然而，在发布这篇文章(Swift 1)时，他的代码不能在Swift 2.0 (Xcode 7)中编译，因为他们删除了advance()函数。更新版本如下:
斯威夫特2
extension String {
func rangeFromNSRange(nsRange : NSRange) -> Range<String.Index>? {
let from16 = utf16.startIndex.advancedBy(nsRange.location, limit: utf16.endIndex)
let to16 = from16.advancedBy(nsRange.length, limit: utf16.endIndex)
if let from = String.Index(from16, within: self),
let to = String.Index(to16, within: self) {
return from ..< to
}
return nil
}
}
斯威夫特3
extension String {
func rangeFromNSRange(nsRange : NSRange) -> Range<String.Index>? {
if let from16 = utf16.index(utf16.startIndex, offsetBy: nsRange.location, limitedBy: utf16.endIndex),
let to16 = utf16.index(from16, offsetBy: nsRange.length, limitedBy: utf16.endIndex),
let from = String.Index(from16, within: self),
let to = String.Index(to16, within: self) {
return from ..< to
}
return nil
}
}
斯威夫特4
extension String {
func rangeFromNSRange(nsRange : NSRange) -> Range<String.Index>? {
return Range(nsRange, in: self)
}
}
