iOS 7 introduced the concept of a translucent tab/nav/status bar.
In doing so, view controllers “extend” their views so that it is beneath the bar, giving a there-but-not-there-blurry effect.
To help view controllers to adapt to this iOS 7 concepts, know this:
- the view is now expanded to beneath the bar(s)
- to know the area that is NOT beneath the bar, you have to use the top & bottom layout guide (these are 2 properties in view controller)
- hence when you add subviews, they should usually be between the layout guides
- however, for scroll view, they should extend beyond the guides, with an inset using the layout guides
If you have Scroll View with Translucent Bar
Assuming you use scroll view (including table/collection views) with a translucent nav and tab bar, this is how you configure your storyboard for the view controller:
- Enable Adjust Scroll View Insets
- Enable Under Top Bars
- Enable Under Bottom Bars
- Pin the scroll view to Superview top, bottom, left, right
Why this works?
When you enable Under Top/Bottom Bars, it tells the view controller’s root view to extend the edges. Programatically you can set edgesForExtendedLayout.
We make the scroll view the same rect as it’s superview, that is the view controller’s root view.
Then enable Adjust Scroll View Insets so that view controller automatically make the inset fall between the top & bottom layout guide!
Trivial
The top and bottom layout guides are UILayoutSupport protocol implemented by UIViewController.
It is not UILayoutGuide.
UILayoutGuide is a different object. It is a useful object if you have constructed dummy views, or container views, merely to help with autolayout.
It replace the heavyweight dummy views with this lightweight object, which you can continue to place autolayout constraints with other views.