What happens to an iPhone app when iPhone goes into stand-by mode?

by

Although it’s not evident here, I believe the original poster did find an answer to his question by starting a thread (available here) in the iPhone Developer Forums (which I eventually had to find myself because the information wasn’t shared here).

In case someone else has the same question and finds the page in the future, here’s a helpful response that was posted by someone on the Apple forum called “eskimo1” (which I have edited slightly such that it is easier to read without having the context provided by the entire original thread):

  • Regarding iPhone app status terminology, “active” does not mean “awake”, it means “attached to the GUI”. Think of it being analogous to “frontmost” in Mac OS X. When you lock the device your app deactivates but the device may or may not go to sleep
  • iPhone OS rarely sleeps if the device is connected to main power (i.e., via USB). It can sleep if running on battery, however.
  • A short time after the screen is locked (20 seconds according to Oliver Drobnik), the device sleeps. This is like closing the lid on your laptop; all activity on the main CPU halts.
  • This does not happen if the device is playing audio in the right audio session. See DTS Q&A QA1626 “Audio Session – Ensuring audio playback continues when screen is locked” for details.
  • Note that the idleTimerDisabled property (which can be turned on to prevent the screen from turning off while the app is running) is about locking the screen after user inactivity. It’s not directly related to system sleep (it’s indirectly related in that the system may sleep shortly after it’s locked).

More Related Contents:

  1. Finding the direction of scrolling in a UIScrollView?
  2. How to send json data in the Http request using NSURLRequest
  3. iPhone viewWillAppear not firing
  4. Build Error – missing required architecture i386 in file
  5. Objective-C – When to use ‘self’
  6. Difference between [UIImage imageNamed…] and [UIImage imageWithData…]?
  7. Convert image to grayscale
  8. UIImage rounded corners
  9. How do I reset after a UIScrollView zoom?
  10. MKPinAnnotationView: Are there more than three colors available?
  11. NSMutableString as retain/copy
  12. Moving UITabBarItem Image down?
  13. Best Cocoa/Objective-C Wrapper Library for SQLite on iPhone [closed]
  14. Moving a CLLocation by x meters
  15. Annotation details after detail disclosure pressed?
  16. subclassing UIWindow while using storyboards
  17. Reference from UITableViewCell to parent UITableView?
  18. Access App Identifier Prefix programmatically
  19. Drag UIView around Shape Comprised of CGMutablePaths
  20. Blocks instead of performSelector:withObject:afterDelay: [duplicate]
  21. Difference between two NSDate objects — Result also a NSDate
  22. Subview appears underneath superviews layer.border?
  23. UIViewController -viewDidLoad not being called
  24. Check iOS version at runtime?
  25. How to Dismiss 2 Modal View Controllers in Succession?
  26. How do I programmatically zoom a UIScrollView?
  27. Get video NSData from ALAsset url iOS
  28. How to detect edit mode on iPhone UITableView
  29. Problem dealloc’ing memory used by UIImageViews with fairly large image in an UIScrollView
  30. Loop an UIScrollView [duplicate]

Leave a Comment