Why is applicationState being returned as nil?

Question

I'm trying to check the application state of my iOS app, but when I check

[UIApplication sharedApplication].applicationState

I'm getting nil. I checked that [UIApplication sharedApplication] is not nil. I'm basically just checking whether or not the screen is on, so I'm just checking the result of the following:

[UIApplication sharedApplication].applicationState == UIApplicationStateActive

Any idea why I'm getting nil returned?

`UIApplicationState` is an `enum` so `nil` doesn't make sense. — trojanfoe, Feb 22 '13 at 16:06
Perhaps you are confusing `UIApplicationStateActive` (value `0`) with `nil`? — trojanfoe, Feb 22 '13 at 16:09
@trojanfoe I'm debugging and after the line 'UIApplicationState *applicationState = [UIApplication sharedApplication].applicationState;' I query 'po applicationState' and get '$4 = 0x00000000 ' — ferson2020, Feb 22 '13 at 16:10
`UIApplicationState` is not a class; it's an enum. `UIApplicationStateActive` == 0, so that makes sense. — Alex, Feb 22 '13 at 16:15

score 3 · Accepted Answer · answered Feb 22 '13 at 16:11

3

OK your code is incorrect (I'm surprised it compiled):

UIApplicationState *applicationState = [UIApplication sharedApplication].applicationState;

Should be:

UIApplicationState applicationState = [UIApplication sharedApplication].applicationState;

(it's an enum not an object).

answered Feb 22 '13 at 16:11

trojanfoe

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Thanks, I'm a little unfamiliar with Objective-C enums. – ferson2020 Feb 22 '13 at 16:14
@ferson2020 Yeah the only way to tell if an object is being returned or an `enum` or `typedef` is to look for the pointer operator (`*`). – trojanfoe Feb 22 '13 at 16:19

Why is applicationState being returned as nil?

1 Answers1