Replacement for deprecated sizeWithFont: in iOS 7?

I believe the function was deprecated because that series of NSString+UIKit functions (sizewithFont:..., etc) were based on the UIStringDrawing library, which wasn't thread safe. If you tried to run them not on the main thread (like any other UIKit functionality), you'll get unpredictable behaviors. In particular, if you ran the function on multiple threads simultaneously, it'll probably crash your app. This is why in iOS 6, they introduced a the boundingRectWithSize:...method for NSAttributedString. This was built on top of the NSStringDrawing libraries and is thread safe.

If you look at the new NSString boundingRectWithSize:... function, it asks for an attributes array in the same manner as a NSAttributeString. If I had to guess, this new NSString function in iOS 7 is merely a wrapper for the NSAttributeString function from iOS 6.

On that note, if you were only supporting iOS 6 and iOS 7, then I would definitely change all of your NSString sizeWithFont:... to the NSAttributeString boundingRectWithSize. It'll save you a lot of headache if you happen to have a weird multi-threading corner case! Here's how I converted NSString sizeWithFont:constrainedToSize::

What used to be:

NSString *text = ...;CGFloat width = ...;UIFont *font = ...;CGSize size = [text sizeWithFont:font                constrainedToSize:(CGSize){width, CGFLOAT_MAX}];

Can be replaced with:

NSString *text = ...;CGFloat width = ...;UIFont *font = ...;NSAttributedString *attributedText =    [[NSAttributedString alloc] initWithString:text                                     attributes:@{NSFontAttributeName: font}];CGRect rect = [attributedText boundingRectWithSize:(CGSize){width, CGFLOAT_MAX}                                           options:NSStringDrawingUsesLineFragmentOrigin                                           context:nil];CGSize size = rect.size;

Please note the documentation mentions:

In iOS 7 and later, this method returns fractional sizes (in the size component of the returned CGRect); to use a returned size to size views, you must use raise its value to the nearest higher integer using the ceil function.

So to pull out the calculated height or width to be used for sizing views, I would use:

CGFloat height = ceilf(size.height);CGFloat width  = ceilf(size.width);