LayoutSubViews
View a need to adjust the position at the time of the child's view, be rewritten.
The following method will start calling LayoutSubViews
- init initialization does not trigger layoutSubviews, but is initWithFrame when initialized, when the value of rect is not CGRectZero, will trigger
- addSubview will trigger layoutSubviews
- Set view of Frame trigger layoutSubviews, of course, provided that the value of the front and rear frame has changed
- Scrolling a UIScrollView will trigger layoutSubviews
- Screen rotation layoutSubviews event triggers on the parent UIView
- When changing the size of a UIView layoutSubviews event will trigger on the parent UIView
Refresh UIView internal layout of child controls
The call UIView setNeedsLayout method, the system is marked as the need to re-layout. The system will be called asynchronously view layoutIfNeeded refreshed layout, it does not refresh immediately, but layoutSubviews will be called.
Call the view of layoutIfNeeded method, if there is a marked need to refresh the view, calls LayouSubView immediately layout.
If you want to refresh immediately, first calling [view setNeedsLayout], the need to mark the layout, and then immediately call [view layoutIfNeeded], to achieve layout