How to support dynamic type in labels in iOS 7?

Question

How do I support Dynamic Type in UILabel and UITextView in iOS 7? I'm adapting one of our projects for iOS 7 and would like to support this accessibility feature. I can't find the specific how to tutorial on it on Apple's iOS Developer site.

Solution 1

If you use the new UIFont methods then you're pretty much there - you just need to add the observer to listen for changes.

Rather than setting a specific font size, you should use the preferredFontForTextStyle: and related methods when styling your labels (if you're using Interface Builder you can select a style directly in the inspector). For example:

self.label.font = [UIFont preferredFontForTextStyle:UIFontTextStyleHeadline];

Once you've done that you should listen for the UIContentSizeCategoryDidChangeNotification. When you receive this notification you should layout your labels to support the newly selected size (if you're using autolayout this is normally as simple as sending invalidateIntrinsicContentSize to your views).

If you're looking for official documentation then take a look at the Text Programming Guide.

Solution 2

In Swift 3 and iOS 10 you can use

headline.font = UIFont.preferredFont(forTextStyle: UIFontTextStyleHeadline)
headline.adjustsFontForContentSizeCategory = true

See this excellent post for more information, especially how to support pre iOS 10.