How to render a multiline UILabel with NSMutableAttributedString

Question

I am trying to create a multiline UILabel with an NSMutableAttributedString. This works fine when I assign an attribute to the complete string like this:

UILabel *contentLabel = [[UILabel alloc] initWithFrame:CGRectMake(0,0,200,100)];
[contentLabel setLineBreakMode:NSLineBreakByWordWrapping];
[contentLabel setNumberOfLines:0];
[contentLabel setFont:[UIFont systemFontOfSize:13];

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"hello I am a long sentence that should break over multiple lines"];
[string addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:13] range:NSMakeRange(0, [string length])];

contentLabel.attributedText = string;

But I what I need is to apply a number of attributes for different subranges of the NSAttributedString (to bold certain words).

UILabel *contentLabel = [[UILabel alloc] initWithFrame:CGRectMake(0,0,200,100)];
[contentLabel setLineBreakMode:NSLineBreakByWordWrapping];
[contentLabel setNumberOfLines:0];
[contentLabel setFont:[UIFont systemFontOfSize:13];

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"hello I am a long sentence that should break over multiple lines"];
[string addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:13] range:NSMakeRange(3, 5)];

contentLabel.attributedText = string;

What I am finding is that if I do this, the text isn't rendered over multiple lines in the label anymore. It is rendered as a single line, centered vertically in the label's frame.

Is there something I'm missing here?

Answer 1

As discussed in the question's comments, the code presented in the question actually works correctly, and does render the attributed string as intended. (The problem was elsewhere in my code)