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
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)
}
}
其他回答
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)
Swift 5解决方案
简短的回答带有主要的扩展
extension NSRange {
public init(range: Range<String.Index>,
originalText: String) {
self.init(location: range.lowerBound.utf16Offset(in: originalText),
length: range.upperBound.utf16Offset(in: originalText) - range.lowerBound.utf16Offset(in: originalText))
}
}
详情请看这里
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)
}
}
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
}
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)
}
}
