UIWindow (An object that provides the backdrop for your app’s user interface and provides important event-handling)
- Every view that appears onscreen is enclosed by a window, and each window is independent of the other windows in your app.
- Events received by your app are initially routed to the appropriate window object, which is turn forwards those events to the appropriate view.
Handful tasks of Window Objects:
- Setting the z-axis level of your window, which affects the visibility to the window relative to other windows.
- Showing windows and making them the target of keyboard events.
- Converting coordinate values to and from the window’s
- Changing the root view controller of a window.
- Changing the screen on which the window is displayed.