UILabel

UILabel auto height implementation

• non auto-layout case

  self.mainLabel.lineBreakMode = NSLineBreakByWordWrapping;
  self.mainLabel.numberOfLines = 0;
  NSString *someText = @"this is a really long long message, this is a really long long message, this is a really long long message, this is a really long long message, this is a really long long message, this is a really long long message, this is a really long long message, this is a really long long message-===== end ";
  //key part: calculate the frame size
  CGSize maxSize = CGSizeMake(320.f, FLT_MAX);
  CGRect labRect = [someText boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:self.mainLabel.font} context:nil];
  self.mainLabel.frame = CGRectMake(0, 64, maxSize.width, labRect.size.height);
  self.mainLabel.text = someText;
  

• auto-layout case

  //uilabel inspector: line break mode: word wrap
  //add constrains to the UILabel, height >= some value
  //If you implement UILabel in UItableView, still use boundingRectWithSize to calculate height of UILabel, then calculate the offset accordingly
  

Add underline to text in UILabel

NSDictionary *underlineAttribute = @{NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle)};
myLabel.attributedText = [[NSAttributedString alloc] initWithString:@"Test string" 
                                                         attributes:underlineAttribute];