How can I elegantly dismiss view if at the moment of dismissing I don't know that view is fully created?

Question

How can I elegantly dismiss view if at the moment of dismissing I don't know if that view is fully created ?

Here is my dilemma. The view is showing some data that is requested from the server. Therefore I asynchronously send server request from viewDidLoad and wait in two observers if request failed or not.

For "dismissing" view I use exit segue (storyboard).

So there are two scenarios:

• Server-side error occurred after viewDidAppear was called. Then I can call performSegue or self.navigationController.pop... and everything is nice.
• Server-side error occurred before viewDidAppear was called. How can I navigate user to previous view in this case ?

For now I just put server request to viewDidAppear but it's very uncool because user looks at empty view for significant amount of time :(

How would you deal with this ?

Answer 1

UPDATED Make a flag, ie

@property (nonatomic, assign) BOOL requestFailedOrViewDidAppear;

set it to NO at start of viewDidLoad or in init method. Then in your server-side error handler do something like this:

if (requestFailedOrViewDidAppear) {
    //return to previous view
}
else {
    requestFailedOrViewDidAppear = YES;
}

Put the same code into viewDidAppear, too.

That is more elegant in terms of implementation. However if you want it to be elegant in terms of UI/UX, replace "//return to previous view" with code that creates and shows a UIAlertView explaining the error. Then, when user dismisses that alert view, you can return to the previous view.

Answer 2

Assuming that your user will expect some info to be shown on the view that's being presented, If the request fails before viewDidAppear , I would wait until view appears, show the error, and dismiss the view. Else if request fails after viewDidAppear , I would just show the error and dismiss the view on the request observing method. That would be my way of dealing with this problem.

Answer 3

Turned out there is int flag in UIViewController that is called _appearState . When it's 2 that means view has appeared.