Different styles for links in a UITextView - ios

Question

I want my UITextView includes plain text, links, phone numbers and other UIDataDetectorTypes. For instance, plain text - black color, links - blue color with underline, hashtags - green color. So, I parse text and add links to hashtags:
[attributedString addAttribute:NSLinkAttributeName value:[NSString stringWithFormat:#"hashtag://%#", hashtag] range:range];
Other links are detected by default, if dataDetectorTypes set to UIDataDetectorTypeAll. But how to change link style for hashtags?

Answer 1

You can use the official Twitter library for tracking hashtags called twitter text along with TTTAttributedLabel.
Hashtags have special conditions, these could be more than alphanumeric characters preceded by #.
The twitter-text library will automatically find the ranges of hashtags for you then you should be able to format it with TTTAttributedLabel.
Here is a sample implementation of both libraries together.
- (void)scanForHashtag:(NSArray *)hashtags fromLabel:(id)sender
{
TTTAttributedLabel *label = (TTTAttributedLabel *)sender;
for (TwitterTextEntity *entity in hashtags) {
UIFont *boldSystemFont = [UIFont fontWithName:#"Helvetica-Bold" size:12];
CTFontRef font = CTFontCreateWithName((__bridge CFStringRef)boldSystemFont.fontName, boldSystemFont.pointSize, NULL);
NSArray *keys = [[NSArray alloc] initWithObjects:(id)kCTForegroundColorAttributeName,(id)kCTUnderlineStyleAttributeName,(NSString *)kCTFontAttributeName, nil];
UIColor *hashtagColor;
hashtagColor = [UIColor greenColor];
NSArray *objects = [[NSArray alloc] initWithObjects:hashtagColor,[NSNumber numberWithInt:kCTUnderlineStyleNone],(__bridge id)font, nil];
NSDictionary *linkAttributes = [[NSDictionary alloc] initWithObjects:objects forKeys:keys];
label.linkAttributes = linkAttributes;
NSString *hashtag = [label.text substringWithRange:entity.range];
if (entity.type == 2) { //Hashtag
[label addLinkToPhoneNumber:hashtag withRange:entity.range];
} else if (entity.type == 0) { //URL
NSURL *url = [NSURL URLWithString:[label.text substringWithRange:entity.range]];
[label addLinkToURL:url withRange:entity.range];
}
}
}
- (void)attributedLabel:(TTTAttributedLabel *)label didSelectLinkWithPhoneNumber:(NSString *)phoneNumber
{
//Do whatever you need when the hashtag is tapped.
}
[self scanForHashtag:[TwitterText hashtagsInText:#"The text that contains the tweet with hashtags." checkingURLOverlap:NO] fromLabel:yourLabel]; //yourLabel is the label that contains the text so it would be formatted.
EDIT FOR UITextView
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:str];
[attributedString addAttribute:NSBackgroundColorAttributeName
value:[UIColor yellowColor]
range:entity.range];

Answer 2

You need to find hashtags ranges and than add special attributes for them.
For example.
NSError *error = nil;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:#"YOUR HASHTAG PATTERN" options:0 error:&error];
if (!error) {
[regex enumerateMatchesInString:messageText options:0 range:NSMakeRange(0, messageText.length) usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
[mutableAttributedString addAttributes:#{
NSFontAttributeName: [UIFont fontLinkMessageCell],
(__bridge NSString*) kCTForegroundColorAttributeName: [UIColor colorLinkOutCell],
NSUnderlineStyleAttributeName: #(NSUnderlineStyleNone),
} range:result.range];
}];
}

Answer 3

self.textView.linkTextAttributes = #{};
self.textView.textStorage.delegate = self;
- (void) textStorage: (NSTextStorage*) textStorage didProcessEditing: (NSTextStorageEditActions) editedMask range: (NSRange) editedRange changeInLength: (NSInteger) delta
{
[textStorage enumerateAttribute: NSLinkAttributeName
inRange: editedRange
options: 0
usingBlock: ^(id value, NSRange range, BOOL* stop)
{
if (value)
{
[textStorage addAttribute: NSForegroundColorAttributeName
value: [UIColor redColor]
range: range];
}
}];
}