What is objc_setAssociatedObject() and in what cases should it be used?

by

objc_setAssociatedObject adds a key value store to each Objective-C object. It lets you store additional state for the object, not reflected in its instance variables.

It’s really convenient when you want to store things belonging to an object outside of the main implementation. One of the main use cases is in categories where you cannot add instance variables. Here you use objc_setAssociatedObject to attach your additional variables to the self object.

When using the right association policy your objects will be released when the main object is deallocated.

More Related Contents:

  1. how to save the data in sqlite3 in iphone
  2. Rounded UIView using CALayers – only some corners – How?
  3. Get push notification while App in foreground iOS
  4. How to send json data in the Http request using NSURLRequest
  5. To ARC or not to ARC? What are the pros and cons? [closed]
  6. Display clearColor UIViewController over UIViewController
  7. When should I release objects in -(void)viewDidUnload rather than in -dealloc?
  8. GCD, Threads, Program Flow and UI Updating
  9. Consume WCF Web Service using Objective-C on iPhone
  10. What exactly does @synthesize do?
  11. How to change a particular color in an image?
  12. How should I store UIImages within my Core Data database?
  13. Where can I find a CSV to NSArray parser for Objective-C? [closed]
  14. Return to app behavior after phone call different in native code than UIWebView
  15. iPhone: How to Pass Data Between Several Viewcontrollers in a Tabbar App
  16. Post photo on user’s wall using Facebook iOS SDK
  17. How to create singleton class in objective C
  18. NSMutableString as retain/copy
  19. Prefixing property names with an underscore in Objective C [duplicate]
  20. Drawing Smooth Curves – Methods Needed
  21. NSDateFormatter, am I doing something wrong or is this a bug?
  22. Draw another image on a UIImage
  23. NSString to NSArray
  24. How to create subscript characters that’s not in Unicode in iOS
  25. Retrieving current local time on iPhone?
  26. Iphone UITextField only integer
  27. Accessing UITextField in a custom UITableViewCell
  28. How to tint UIBarButtonItem background color? [duplicate]
  29. iOS – Scale and crop CMSampleBufferRef/CVImageBufferRef
  30. How to set font size to fill UILabel height?

Leave a Comment