重写layoutSubviews

init does not cause layoutSubviews to be called (duh)

addSubview causes layoutSubviews to be called on the view being added, the view it’s being added to (target view), and all the subviews of the target view

setFrame intelligently calls layoutSubviews on the view having it’s frame set only if the size parameter of the frame is different

scrolling a UIScrollView causes layoutSubviews to be called on the scrollView, and it’s superview

rotating a device only calls layoutSubview on the parent view (the responding viewControllers primary view)

removeFromSuperview – layoutSubviews is called on superview only (not show in table)