Application windows are expected to have a root view controller throwing warning

Question

Im getting this warning "Application is expected to have a root view controller at the end of application launch". Ive read all the other answers and I know why its doing it, but im not sure how to get around it.

I have the following code in my viewDidLoad that is causing the error

//animated header that displays errors over status bar
self.dropdown = [[UIWindow alloc] initWithFrame:CGRectMake(0, -20, 320, 20)];
self.dropdown.backgroundColor = [UIColor redColor];
self.label = [[UILabel alloc] initWithFrame:self.dropdown.bounds];
self.label.textAlignment = NSTextAlignmentCenter;
self.label.font = [UIFont systemFontOfSize:12];
self.label.backgroundColor = [UIColor clearColor];
[self.dropdown addSubview:self.label];
self.dropdown.windowLevel = UIWindowLevelStatusBar;
[self.dropdown makeKeyAndVisible];
[self.dropdown resignKeyWindow];

//needed to hide empty cells at the end of table view.
self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];

If i put that code in viewWillAppear, i dont get the error. THe problem is I dont want it there. I want it in view did load so it only runs once. Can I just ignore the warning, or can I manually set the root in my app delegate or something. I really want to keep it in view did load. Im using storyboards.

Thanks

You didn't specified any view controller as the root view controller of the window you created — Midhun MP, Dec 20 '13 at 06:32
show your `didFinishLaunchingWithOptions` method of app delegate. — Toseef Khilji, Dec 20 '13 at 06:35
@midhunMP, that was it! thanks so much dont know how I missed that. You can go ahead and add that as an answer and ill accept it. — Stonep123, Dec 20 '13 at 06:36

Midhun MP · Answer 1 · 2013-12-20T06:56:31.650

1

Issue is you didn't specified any view controller as the root view controller of the window you created.

Just set it like:

self.dropdown.rootViewController = yourViewController;

Suggestion:

Don't use multiple windows in an application. It is better to use only one window in your application and multiple view controllers and views. I saw an issue in my career, issue was one of my colleague used multiple windows for displaying different contents instead of view controller, Without proper handling the application crashed 10 times in a minute!!!.

edited Dec 20 '13 at 06:56

answered Dec 20 '13 at 06:51

Midhun MP

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ive tried, but it seems the only way to get this view to animate down over the status bar is to do it this way, using a seperate window. – Stonep123 Dec 20 '13 at 06:53
@Stonep123: then make sure that you handle it well. – Midhun MP Dec 20 '13 at 06:55

rdelmar · Accepted Answer · 2013-12-20T06:49:39.440

0

I don't know why adding another window like this causes this error, when the storyboard creates the root view controller (for the main window that is), but you can suppress it by moving all the code to a separate method and calling it with a slight delay (using performSelector:withObject:afterDelay:) from viewDidLoad.

edited Dec 20 '13 at 06:49

answered Dec 20 '13 at 06:41

rdelmar

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well I set the root view controller of that new window to self (my view controller) and it seemed to fix it. – Stonep123 Dec 20 '13 at 06:43
@Stonep123, I guess that works, but I don't know if it's a good thing to have the same controller be the root view controller of two different windows. Maybe that's ok, it just seems kind of strange. – rdelmar Dec 20 '13 at 06:46
ive not used selectors before, could you explain how I would call that performSelectorMethod if I put all the setup code into the method (void)headerSetup – Stonep123 Dec 20 '13 at 06:49
@Stonep123, [self performSelector:@selector(createDropdown) withObject:nil afterDelay:0.1]; Then move your code to a new method called createDropdown. – rdelmar Dec 20 '13 at 06:51

Application windows are expected to have a root view controller throwing warning

2 Answers2