A set of methods that define the focus behavior for a branch of the view hierarchy.
UIFocusEnvironment protocol provides a common interface for specifying and reacting to focus behavior throughout your app. Classes in UIKit that conform to this protocol include
UIPresentationController; in other words, classes that are either directly or indirectly in control of views on the screen. Third-party classes should not conform to the
Requesting Focus Update
When to request a focus update.
Validating Focus Movements
Responding to Focus Updates
Controlling User-Generated Focus Movements
Checking the Ancestory of the Environment
Getting the Sound to Play During Updates
A protocol—not intended for conformance by third-party classes—that lets an item declare its ability to participate in the focus system.
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