ios - 用于 Swift 的 NSNotFound

Question

我通过 Antony 找到了这个解决方案用于验证 URL。

- (BOOL)isValidURL {
    NSUInteger length = [self length];
    // Empty strings should return NO
    if (length > 0) {
       NSError *error = nil;
       NSDataDetector *dataDetector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
       if (dataDetector && !error) {
          NSRange range = NSMakeRange(0, length);
          NSRange notFoundRange = (NSRange){NSNotFound, 0};
          NSRange linkRange = [dataDetector rangeOfFirstMatchInString:self options:0 range:range];
          if (!NSEqualRanges(notFoundRange, linkRange) && NSEqualRanges(range, linkRange)) {
             return YES;
          }
       }
       else {
          NSLog(@"Could not create link data detector: %@ %@", [error localizedDescription], [error userInfo]);
       }
    }
    return NO;
}

我想尝试一下，但我正在快速编码。这是我目前所拥有的。

extension String{
    func isValidURL() -> Bool{
         let length:Int = self.characters.count
         var err:NSError? = nil
         let dataDetector:NSDataDetector?
         do{
             dataDetector = try NSDataDetector(types: NSTextCheckingType.Link.rawValue)
         }catch{
             err = error as? NSError
         }
         if dataDetector != nil && err != nil{
             let range = NSMakeRange(0, length)
             let notFoundRange = (NSRange){ NSNotFound, 0 } //How do I format this for swift?
             let linkRange = dataDetector?.rangeOfFirstMatchInString(self, options: 0, range: range)
             if !NSEqualRanges(notFoundRange, linkRange) && NSEqualRanges(range, linkRange){
                 return true
             }
         }else{
            print("Could not create link data detector: \(err?.localizedDescription): \(err?.userInfo)")
         }

         return false
     }
 }

绊脚石是 NSNotFound。据我所知，这就是 swift optionals 的用途。如何格式化该行？

Answer 1

就是aggregate initialization C 中结构的语法。您可以改用 NSRange 初始值设定项:

let notFoundRange = NSRange(location: NSNotFound, length: 0)

或者，也许更简单:

if linkRange.location != NSNotFound { ...