Top layout guide is deprecated in iOS 11

The Obj-C version:

[[searchBackView.topAnchor constraintEqualToAnchor:self.view.safeAreaLayoutGuide.topAnchor constant:0] setActive:YES];

If you have translucent bars note: then the topLayoutGuide is below the bar, e.g the statusBar.

see: topLayoutGuide It explains conditions which is important to consider.

Whereas the safeAreaLayoutGuide.topAnchor would not be beneath the NavigationBars; much simpler to work with.

TopLayoutGuide is deprecated in iOS 11 so we have option to use SafeAreaLayoutGuide like this :

• First we can get view safeAreaLayoutGuide

 let guide = view.safeAreaLayoutGuide

• Second add constraint to guide

  searchBackView.topAnchor.constraint(equalTo: guide.topAnchor).isActive = true