viewWillAppear is not called in the master view of UISplitViewController - ios

Question

I have a splitvew controller (set in storyboard) with master and detail, and I set the preferredDisplayMode as UISplitViewControllerDisplayModeAllVisible in the master viewController.
I have these method on the master view controller:
- (void) viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
//This is called
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
//This is not called
[self.searchController.searchBar sizeToFit];
[self configNavBar]; //Adds few buttons to the nav bar
}
I'm wondering why the viewwillAppear isn't called here but viewDidLoad, viewDidAppear are called. The breakpoint in the viewWillAppear didn't hit .
If I set the preferred display mode as UISplitViewControllerDisplayModePrimaryOverlay, then viewWillAppear is getting called.
But here the detail view controller doesn't occupy the half screen.

Answer 1

I know its an old one but I have the same problem here. On iPad, no problem, the viewWillAppear is called but on iPhone it is not called at all the first time i display the controller.
I finally found that it was due to the call of this lines of code:
if let target = displayModeButtonItem.target, let action = displayModeButtonItem.action {
UIApplication.shared.sendAction(action, to: target, from: view, for: nil)
}
which was called after the initialization of my UISplitViewController.
When I removed this, it worked. But I was also able to bypass it by using the mode: .primaryHidden on iPhone (I dont use the iPhone on landscape thats why my condition on this example will be iPhone / iPad). So my custom UISplitViewController look like this:
override func viewDidLoad() {
super.viewDidLoad()
self.preferredDisplayMode = UIDevice.current.userInterfaceIdiom == .pad ? .allVisible : .primaryHidden
}
Hope this could help someone.