我想实现的目标如下。我有一个NSString，其中包含一个句子和一个URL。我需要能够从任何NSString中提取出所呈现的URL。例如：
假设我有这个NSString：
NSString *someString = @"This is a sample of a http://example.com/efg.php?EFAei687e3EsA sentence with a URL within it.";
NSDataDetector：NSString *string = @"This is a sample of a http://example.com/efg.php?EFAei687e3EsA sentence with a URL within it.";
NSDataDetector *linkDetector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:nil];
NSArray *matches = [linkDetector matchesInString:string options:0 range:NSMakeRange(0, [string length])];
for (NSTextCheckingResult *match in matches) {
if ([match resultType] == NSTextCheckingTypeLink) {
NSURL *url = [match URL];
NSLog(@"found URL: %@", url);
}
}
这样，您就不必依赖不可靠的正则表达式，而且当苹果升级其链接检测代码时，您可以免费获得这些改进。
NSTextCheckingResult 可以告诉您匹配子字符串的范围，然后您可以将其与 substringWithRange: 一起使用。 - Dave DeLong编辑：我要冒险说一句，你可能应该使用Dave提到的NSDataDetector。比正则表达式更不容易出错。
请看正则表达式。您可以使用NSRegularExpression类构建一个简单的正则表达式来提取URL，或者找一个可用的在线正则表达式。有关使用这个类的教程，请参见此处。
您需要的代码基本上看起来像这样（使用John Gruber的超级URL正则表达式）：
NSRegularExpression *expression = [NSRegularExpression regularExpressionWithPattern:@"(?i)\\b((?:[a-z][\\w-]+:(?:/{1,3}|[a-z0-9%])|www\\d{0,3}[.]|[a-z0-9.\\-]+[.][a-z]{2,4}/)(?:[^\\s()<>]+|\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\))+(?:\\(([^\\s()<>]+|(\\([^\\s()<>]+\\)))*\\)|[^\\s`!()\\[\\]{};:'\".,<>?«»“”‘’]))" options:NSRegularExpressionCaseInsensitive error:NULL];
NSString *someString = @"This is a sample of a http://example.com/efg.php?EFAei687e3EsA sentence with a URL within it.";
NSString *match = [someString substringWithRange:[expression rangeOfFirstMatchInString:someString options:NSMatchingCompleted range:NSMakeRange(0, [someString length])]];
NSLog(@"%@", match); // Correctly prints 'http://example.com/efg.php?EFAei687e3EsA'
这将从任何字符串中提取第一个URL（当然，这没有错误检查，所以如果字符串确实不包含任何URL，则它将无法工作，但是请查看NSRegularExpression类以了解如何解决此问题。
使用方法如下:
NSError *error = nil;
NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink
error:&error];
[detector enumerateMatchesInString:someString
options:0
range:NSMakeRange(0, someString.length)
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop)
{
if (result.resultType == NSTextCheckingTypeLink)
{
NSString *str = [NSString stringWithFormat:@"%@",result.URL];
NSLOG(%@,str);
}
}];
使用这个：
NSURL *url;
NSArray *listItems = [someString componentsSeparatedByString:@" "];
for(int i=0;i<[listItems count];i++)
{
NSString *str=[listItems objectAtIndex:i];
if ([str rangeOfString:@"http://"].location == NSNotFound)
NSLog(@"Not url");
else
url=[NSURL URLWithString:str];
}
Swift 2 :
let input = "This is a test with the URL https://www.hackingwithswift.com to be detected."
let detector = try! NSDataDetector(types: NSTextCheckingType.Link.rawValue)
let matches = detector.matchesInString(input, options: [], range: NSMakeRange(0, input.characters.count))
for match in matches {
let url = (input as NSString).substringWithRange(match.range)
print(url)
}
let string = "here is the link www.google.com"
let types: NSTextCheckingType = [ .Link]
let detector = try? NSDataDetector(types: types.rawValue)
detector?.enumerateMatchesInString(string, options: [], range: NSMakeRange(0, (string as NSString).length)) { (result, flags, _) in
if(result?.URL != nil){
print(result?.URL)
}
}
- (void)parseURLs:(NSString*)string {
NSInteger index = 0;
while (index < string.length) {
NSRange searchRange = NSMakeRange(index, string.length - index);
NSRange startRange = [string rangeOfString:@"http://" options:NSCaseInsensitiveSearch
range:searchRange];
if (startRange.location == NSNotFound) {
NSString* text = [string substringWithRange:searchRange];
TTStyledTextNode* node = [[[TTStyledTextNode alloc] initWithText:text] autorelease];
[self addNode:node];
break;
} else {
NSRange beforeRange = NSMakeRange(searchRange.location, startRange.location - searchRange.location);
if (beforeRange.length) {
NSString* text = [string substringWithRange:beforeRange];
TTStyledTextNode* node = [[[TTStyledTextNode alloc] initWithText:text] autorelease];
[self addNode:node];
}
NSRange searchRange = NSMakeRange(startRange.location, string.length - startRange.location);
NSRange endRange = [string rangeOfString:@" " options:NSCaseInsensitiveSearch
range:searchRange];
if (endRange.location == NSNotFound) {
NSString* URL = [string substringWithRange:searchRange];
TTStyledLinkNode* node = [[[TTStyledLinkNode alloc] initWithText:URL] autorelease];
node.URL = URL;
[self addNode:node];
break;
} else {
NSRange URLRange = NSMakeRange(startRange.location,
endRange.location - startRange.location);
NSString* URL = [string substringWithRange:URLRange];
TTStyledLinkNode* node = [[[TTStyledLinkNode alloc] initWithText:URL] autorelease];
node.URL = URL;
[self addNode:node];
index = endRange.location;
}
}
}
}
[self addNode:node];，都会添加一个找到的URL。这应该可以让你开始工作！希望这有所帮助。 :)NSRegularExpression类是没有必要的。 - Itai FerberSwift 4.x
Xcode 12.x
let string = "This is a test with the URL https://www.hackingwithswift.com to be detected. www.example.com"
let types: NSTextCheckingResult.CheckingType = [ .link]
let detector = try? NSDataDetector(types: types.rawValue)
detector?.enumerateMatches(in: string, options: [], range: NSMakeRange(0, (string as NSString).length)) { (result, flags, _) in
if(result?.url != nil){
print(result?.url)
}
}