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iOS Implementing Designs for iPhone Implementing Custom Login and Sign Up Screens Hiding the Navigation Bar

There's an error

When I run my app with not logged in user performs "showLogin" seque and I see LoginViewController. If i would try to swipe from left side to right (it is the same as back button in NavigationController) navigation controller would try to pop the previous view controller and then error happens. Error without description. I can't understand why it happens. It seems to me that the InboxViewController should appear.

6 Answers

It's been a while since I did this course, so I don't remember how the login screen segue was implemented. But it would seem that you shouldn't be able to go to the inbox at all if not logged in. If your navigation controller is trying to pop the login screen without being logged in, then something is wrong.

Is the login screen presented modally

Login screen isn't modal. There's a push-segue. The previous course where I build Ribbit app was upon iOs 6. There was no such gesture (swipe for pop previous view controller). So we just hided back button. There's an logical problem. I think we must check logged in user or not in AppDelegate instead of ViewController. But there's another question. Why app crashes when trying to display InboxViewController with not logged in user.

I've found out what is the error. I have checking for logged in user in viewDidLoad method of InboxViewController. I must replace it to the viewWillAppear

In the viewDidAppear of InboxViewController we try to perform PFQuery using currentUser which is null. So app crashes.

Ahh - ok... so do something like

if currentUser != nil {
    //do query stuff
} else {
    //tell the user to log in

I really would still suggest that you present the view modally though.

Ok... if the user is not supposed to be able to "go back" from the login view without login in, then that view really should be presented modally. There are a couple of ways you can prevent the navigation controller from responding to the swipe, but the implementation changes between versions of iOS, and apparently doing so is cause for rejection at the app store.

So - present the view modally :)

Thank you, Rasmus!

Any time :)