NSError *error = NULL;

NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];

NSUInteger numberOfMatches = [detector numberOfMatchesInString:text options:0 range:NSMakeRange(0, text.length)];

if (!error && numberOfMatches > 0) {

    NSLog(@"Error: %@ Matches: %lu", error.description, numberOfMatches);

    // It's a valid URL.

}
else {

    NSLog(@"Error: %@ Matches: %lu", error.description, numberOfMatches);

    // Google search
}

return YES;