Automatic Link Detection in an NSTextView

NSTextView is a really powerful text view class. It can do all kinds of stuff like automatic spelling correction, email, phone number, and address detection, and link detection. I was working on a chat application and I wanted to have links that people sent be clickable. I was using an NSTextView because it has the automaticLinkDetection property.

Unfortunately, I couldn’t get links to show up in my app. I tried sending it delegate messages and lots of other stuff. It just wouldn’t work when I set the text programatically. It would only work when I was actually typing in to the NSTextView and even then, it was a little flaky. I posted a question on StackOverflow and didn’t get any answers.

So to fix the problem, I did the link detection myself. I look through the text view for links and then add them myself as NSAttributedStrings. I did this using three different categories.

There is NSAttributedString+Hyperlink, NSString+FindURLs, and NSTextView+AutomaticLinkDetection. I use the FindURLs category to find the links and their locations, then I use the Hyperlink category to format the string like a link, and the AutomaticLinkDetection category to bring them together.

You use it like this

   [myTextView setString:@"http://google.com http://apple.com"];
   [myTextView detectAndAddLinks];

And here is the implementation

-(void)detectAndAddLinks
{
   NSArray *linkLocations = [[self string] locationsOfLinks];
   NSArray *links = [[self string] arrayOfLinks];

   int i=0;
   for( NSString *link in links )
   {
      NSAttributedString *linkString = [NSAttributedString hyperlinkFromString:link withURL:[NSURL URLWithString:link]];
      [[self textStorage] replaceCharactersInRange:[[linkLocations objectAtIndex:i] range] withAttributedString:linkString];
      i++;
   }

}

I put an example project on GitHub that you can look at and use.

Let me know if there was something I missed that would make it so I don’t have to use the category.