iOS SDK Release Notes for IOS 8.3 Beta 4 excerpt (UIKit)

(There is no word translation, I hope to understand, if there is something wrong, please correct me)

UIKit
NoteNoteWhen linking against IOS 8.3, any code this relies on layout information (such as the frame) of a UIButtonSubview when the button isn't in the window hierarchy would need to send layoutIfNeededTo the button before retrieving layout information (such as button.titleLabel.frame) To ensure the layout values is up to date.when compiling a link under iOS8.3, if UIButton (including subclasses) is not a window-level control, any code that involves getting and manipulating the layout information of UIButton (including subclasses), You should first send a layoutifneeded event (in fact, the Layoutifneed method that executes UIButton) to make sure that the UIButton layout information you get is up-to-date.

For example, if you had something like this:

For example, if iOS8.3 before, you write code like this:

UIButton *button = [UIButton Buttonwithtype:uibuttontypesystem];

Code that sets the button, but doesn ' t yet add it to a window

CGRect titleframe = button.titleLabel.frame;

Code that relies on the correct value for Titleframe

You now need: Then, you need to write code like this:

UIButton *button = [UIButton Buttonwithtype:uibuttontypesystem];

Code that sets the button, but doesn ' t yet add it to a window

[Button layoutifneeded]; This is also safe Pre-ios 8.3

CGRect titleframe = button.titleLabel.frame;

Code that relies on the correct value for Titleframe

iOS SDK Release Notes for IOS 8.3 Beta 4 excerpt (UIKit)