Check for user in session in AppDelegate and trigger UIViewController if not

Thanks Stone Preston ! Will this work for when the app becomes active from background with a different view controller in context?

I am doing this to deal with state restoration while also looking for user in session:

func application(application: UIApplication, shouldRestoreApplicationState coder: NSCoder) -> Bool {
    return userInSession != nil
}

Am I missing anything here? Advise is much appreciated! Thanks!

Also, I'm not able to perform the segue. It complains:

2014-12-14 23:42:52.910 appname[78187:18685210] Warning: Attempt to present < appname.LoginUIViewController: 0x7fdcc1616970> on < appname.HomeUITabBarViewController: 0x7fdcc1746610> whose view is not in the window hierarchy!

I'm trying to perform it in viewWillAppear. A related post I found is here: http://stackoverflow.com/questions/15659526/how-to-fix-the-warning-view-is-not-in-the-window-hierarchy

If I transfer the code to viewDidAppear, I see the HomeUITabBarViewController before the LoginUIViewController shows up.

Any ideas?

are you performing the segue from a tabBarController or a ViewController?

Tab bar view controller

thats probably the issue. you need to present from a child view controller of the tab bar, not the tab bar itself

Hmm..meaning that I'll need to segue from every tab's view controller? What will the single point of entry be in this case? My tab bar controller is set to be the initial view controller.

My tab bar controller is set to be the initial view controller.

yes, but the first thing the user actually sees is the view controller thats in the first tab correct. That would be the initial point of entry/exit

meaning that I'll need to segue from every tab's view controller?

no, if the user logs out from the initial tab, you only need a segue from that tab.

The way it should work is the app launches and the first tab will be getting ready to be displayed. before it shows you check to see if the user is logged in, if not perform the segue to the login view.

if they are logged in you dont do anything. When the user logs out from that initial tab you can perform the segue to the login view like before

if you want the user to be able to log out from anywhere in the app you might want to find a way to perform the segue from the tab bar controller, although im not sure how good of an idea that is, never really done it before

Hmm..okay that makes sense. So my first tab is a navigation controller leading up to a table view controller. I put the segue from the table view controller. But this time, although it doesn't throw error when using viewWillAppear, the view still appears before the login view controller is brought in. I'm using a modal segue.

Thoughts?

are you sure you implemented viewWillAppear and not viewDidAppear? if you are using a modal segue you may need to disable the animation in the attributes of the segue

Yep. This is what I got:

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(true)

    if PFUser.currentUser() == nil {

        self.performSegueWithIdentifier("<...>", sender: self)
    }
}

Also, disabling animation still shows the table view controller before the login view controller appears on screen without animation.

pass the animated paramter to the super call, not true. see if that fixes it:

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    if PFUser.currentUser() == nil {

        self.performSegueWithIdentifier("<...>", sender: self)
    }
}

Yeah that makes sense. The result is same though. Sometimes the login view controller appears quickly enough that the table view is not seen, but most times the table view controller is seen. Animation is disabled and behaves as expected.

try a push segue instead and see what happens

The table view controller still shows up before the login view controller. In addition, now the login view controller comes in from the right and the top bar and the bottom bar of the table view controller which is embedded into a navigation controller are visible.

top bar and the bottom bar of the table view controller which is embedded into a navigation controller are visible.

yes that is to be expected. you can hide them if you want.

im using pretty much the exact same setup as you and am not having the same issues as you. strange.

are you sure your segue is going from the child view to the login view? if you post your code to github or dropbox ill take a look at it more closely.

First of all, thank you so much for sticking with me on this!

I'll try to put stuff up somewhere and point out to it.

Just some other thoughts:

1. is there a way to have the the child view controller initialize as hidden, and then make it visible if the segue doesn't have to be used? I tried changing this dynamically, and it sorta worked but the background is black instead of white. Ideas?

2. can AppDelegate's applicationDidBecomeActive be used as the single point of entry check for user in session and then just create the login view controller if needed else resume as normal?

1. not sure

2. possible yes. you would ahve to obtain a reference to your view controller and perform the segue using that.

Yeah, I really like the segue approach. Okay, I'm going to research some more. Thanks a lot again!