Truncate UILabel in specific location

Question

I use a table view to show a list of books, where each cell has a UILabel that shows the book\'s name and another UILabel the shows the book\'s aut

Answer 1

This answer is based on https://stackoverflow.com/a/30813691/2123122. Here is the sample code.

@interface CustomLabel()

  @property (nonatomic, retain) NSLayoutManager *layoutManager;
  @property (nonatomic, retain) NSTextContainer *textContainer;
  @property (nonatomic, retain) NSTextStorage *textStorage;

@end

@implementation CustomLabel

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
       self = [super initWithCoder:aDecoder];
       if (self) {
         [self configureTextkitStack];
       }
       return self;
 }
 - (instancetype)initWithFrame:(CGRect)frame {
       self = [super initWithFrame:frame];
       if (self) {
         [self configureTextkitStack];
       }
       return self;
  }

- (void)configureTextkitStack {
      _textContainer = [[NSTextContainer alloc] init];
      _textContainer.lineFragmentPadding = 0;
      _textContainer.maximumNumberOfLines = self.numberOfLines;
      _textContainer.lineBreakMode = self.lineBreakMode;
      _textContainer.widthTracksTextView = YES;

      _layoutManager = [[NSLayoutManager alloc] init];
      [_layoutManager addTextContainer:self.textContainer];

      [_textContainer setLayoutManager:self.layoutManager];

      _textStorage = [[NSTextStorage alloc] init];
      [_textStorage addLayoutManager:self.layoutManager];
      [self.layoutManager setTextStorage:_textStorage];
}

- (NSRange)rangeForTokenInsertion {
      self.textContainer.size = self.bounds.size;
      if (self.attributedText.length > 0 ){
        [self.textStorage setAttributedString:[[NSMutableAttributedString alloc]initWithAttributedString:self.attributedText]];
      }
      if (self.text.length == 0) {
        return NSMakeRange(NSNotFound, 0);
      }

      NSInteger glyphIndex = [self.layoutManager glyphIndexForCharacterAtIndex:self.textStorage.length - 1];
      NSRange range = [self.layoutManager truncatedGlyphRangeInLineFragmentForGlyphAtIndex:glyphIndex];

      return range;
    }

Now you can use this as follows:

 NSRange range = [self.label rangeForTokenInsertion];
 NSString *token = @"...+2 authors";
 if (range.location != NSNotFound ) {
  range.length += token.length;
  range.location -= token.length;
 }
 if (range.location != NSNotFound) {
  NSString *finalString = [self.label.text  stringByReplacingCharactersInRange:range withString:token];
  self.label.text = finalString;
 }

I have created a UILabel subclass called ResponsiveLabel which handles custom truncation token as well as applying styles to patterns like userhandles, URLs, hashtags etc.