

Visualization of iOS Application States - ckrumb
http://koduco.com/2010/11/01/ios-application-states/

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pshapiro
Cute..., and a good start to a UIKit visualization.

By the way, the methods you see in the diagram are to be implemented by a
UIApplicationDelegate. Your UIApplicationDelegate class is usually laid out by
default in new XCode projects. There are the methods currently documented by
Apple.

Monitoring Application State Changes

– application:didFinishLaunchingWithOptions:

– applicationDidBecomeActive:

– applicationWillResignActive:

– applicationDidEnterBackground:

– applicationWillEnterForeground:

– applicationWillTerminate:

– applicationDidFinishLaunching:

Docs here
([http://developer.apple.com/library/ios/#documentation/UIKit/...](http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIApplicationDelegate_Protocol/Reference/Reference.html%23//apple_ref/occ/intf/UIApplicationDelegate))

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colinyoung
Can anyone clarify exactly why a backgrounded application would become
suspended? Obviously, it's supposed to occur when the OS becomes low on
memory, but does the App's icon actually leave the -- for lack of a better
name -- double-tap-dock area?

I've never seen that happen, and nearly every app in my full Springboard is
also in the double-tap app switcher.

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msbarnett
The switcher is merely a list of recently run applications, not a list of
backgrounded applications, which some people have been mistaking it for.

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colinyoung
Ahh.. I think perhaps the fact that isn't immediately obvious was somewhat
intentional on Apple's part.

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Xuzz
They want to make the idea of "running" irrelevant: to the user, it's active
or inactive. No need to manage a list of running programs if what is actually
running is made invisible and unimportant. Makes it simpler.

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glhaynes
Sounds like they may be headed that way with Lion, too - what's seen so far
doesn't have the little lights under dock icons that indicate whether the
application is actually "open" or not.

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Xuzz
Interesting; I hadn't heard that. I feel this trend is good for the future:
less things to manage is less that a user can do wrong.

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d_r
Comparable chart for Android:

[http://developer.android.com/reference/android/app/Activity....](http://developer.android.com/reference/android/app/Activity.html#ActivityLifecycle)

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brettnak
That chart has been a life saver for me a couple times.

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dongle
This is cool – there were two back-to-back one hour lectures on application
states at WWDC. Absorbing this graphic is obviously faster and easier.

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Zev
The image kinda reminds me of an abstract human heart.

