Using NSRegularExpression to create custom NSDataDetector Type

Question

I'm trying to create custom data detectors for content in a UITextView. I'd like to be able to do something like this:

tv.dataDetectorTypes = UIDataDetectorTypeAll;

but instead of UIDataDetectorTypeAll, I want to use my custom UIDataDetector based on the following regular expression:

    NSError *error = nil;        
    NSRegularExpression *regex = [[NSRegularExpression alloc] initWithPattern:@"(ID: [0-9]+)"
                                                                      options:NSRegularExpressionCaseInsensitive
                                                                        error:&error];

I also would like the detected ID to be a link which pushes a UIWebView with a URL + ID combo ( http://www.stack.com?id ) to the nav stack. There should only ever be one id. Any ideas?

Thanks!

Answer 1

This took me all day and I finally found and modified this Ray Wenderlich solution. Apparently this, is a pretty obscure, new feature in iOS 7.

- (NSAttributedString *)makeAttributedAbstract:(NSString*)str
{
    NSMutableAttributedString *mutableAttributedString = [[NSMutableAttributedString alloc] initWithString:str];

    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(PMID: [0-9]+)" options:kNilOptions error:nil];

    NSRange range = NSMakeRange(0, str.length);

    [regex enumerateMatchesInString:str options:kNilOptions range:range usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
        NSRange subStringRange = [result rangeAtIndex:1];
        [mutableAttributedString addAttribute:NSLinkAttributeName value:@"pmid://" range:subStringRange];
    }];

    return (NSAttributedString*)mutableAttributedString;
}


- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange {
    if ([[URL scheme] isEqualToString:@"pmid"]) {

        NSString *pmid = [NSString stringWithFormat:@"http://www.ncbi.nlm.nih.gov/pubmed/%@", [self.sql getPmidForId:self.abstractId] ];

        NSURL *url = [NSURL URLWithString:pmid];
                NSLog(@"pmid: %@", url);
        [self pushWebViewWithURL:url];

        return NO;
    }
    return YES; // let the system open this URL
}

http://www.raywenderlich.com/48001/easily-overlooked-new-features-ios-7#textViewLinks

Answer 2

I think you have to work around this problem because NSDataDetector is limited to the presets.

Look at this answer https://stackoverflow.com/a/19397842/2085504