Why can't I hide the status bar?

Question

I use the following line of code to hide the status bar:

view.window?.windowLevel = UIWindowLevelStatusBar

What is surprising me is that this line of code does not work from within any of the "life cycle" methods of the view: viewDidLoad(), viewWillAppear(:). However, when I create a button and hook it up to an action method the code above works perfectly and hides the status bar behind the window. I want to be able to call view.window?.windowLevel = UIWindowLevelStatusBar in viewDidLoad(). Can anyone please help me understand why it does not work from within the mentioned view "life cycle" methods?

Answer 1

If you only wanted to hide status bar use:

    [[UIApplication sharedApplication] setStatusBarHidden:YES]

Answer 2

Neither in viewDidLoad nor viewWillAppear the view controller is in the view hierarchy, therefore view.window is nil.

You might work around that by using viewDidAppear or access the window using UIApplication.shared.delegate.window instead.

In general it's not a good idea to change the level of the main window though.

Answer 3

Your ViewController will only be able to adjust the status bar if you set View controller-based status bar appearance to YES in your info.plist. Otherwise it is set by global parameters in your plist or proj file.