How to use addSubview in iOS
Issue #344
addSubview can trigger viewDidLayoutSubviews, so be careful to just do layout stuff in viewDidLayoutSubviews
This method establishes a strong reference to view and sets its next responder to the receiver, which is its new superview.
Views can have only one superview. If view already has a superview and that view is not the receiver, this method removes the previous superview before making the receiver its new superview.
When the bounds change for a view controller’s view, the view adjusts the positions of its subviews and then the system calls this method. However, this method being called does not indicate that the individual layouts of the view’s subviews have been adjusted. Each subview is responsible for adjusting its own layout.
Your view controller can override this method to make changes after the view lays out its subviews. The default implementation of this method does nothing.