Must every ivar be a property?

by

It’s not really necessary to declare properties for all ivars. A few points come to mind:

  • If an ivar is only going to be assigned to once during the lifetime of the object, you don’t really gain anything by declaring a property. Just retain/copy/assign during init and then release as necessary during dealloc.
  • If an ivar is going to be changed frequently, declaring a property and always using the accessors will make it easier to avoid memory management errors.
  • You can declare properties in a class extension in the .m file rather than the .h file if the properties and ivars are meant to be private.
  • When targeting iOS 4.0+, you don’t need to declare ivars at all in your header if you define a property and synthesize accessors.

So I generally use properties, but for things like a NSMutableArray that an object allocates during init and uses to hold a bunch of whatevers, I’ll use a plain old ivar since I’ll never be reassigning the ivar.

More Related Contents:

  1. Synthesized property and variable with underscore prefix: what does this mean? [duplicate]
  2. What is the difference between ivars and properties in Objective-C
  3. Is there any reason to declare ivars if you’re using properties exclusively in Objective-C?
  4. Does a private @property create an @private instance variable?
  5. Properties and Instance Variables in Objective-C
  6. How dangerous is it to compare floating point values?
  7. UIView frame, bounds and center
  8. “Thread 1: stopped at breakpoint” error when initializing an NSURL object
  9. UIImage resizing not working properly
  10. Allowing interaction with a UIView under another UIView
  11. Super slow lag/delay on initial keyboard animation of UITextField
  12. Reading and writing images to an SQLite DB for iPhone use
  13. Show screen on first launch only in iOS
  14. Create an array of integers property in Objective-C
  15. Rotating a CGImage
  16. Determining 3G vs Edge
  17. How can I compute a SHA-2 (ideally SHA 256 or SHA 512) hash in iOS?
  18. iOS Background downloads when the app is not active
  19. Use regular expression to find/replace substring in NSString
  20. Post data in Objective C using Json
  21. ARC – The meaning of __unsafe_unretained?
  22. Current location permission dialog disappears too quickly
  23. How do I enable Local Storage in my WebKit-based application?
  24. NSDateFormatter return incorrect date from string
  25. RestKit: How does one post an array of objects?
  26. Use Data From Class Without A New Init
  27. iOS: Compare two NSDate-s without time portion
  28. “Initializer element is not a compile-time constant” why?
  29. Xcode linker error: file too small for architecture x86_64
  30. “Expression is not assignable” — Problem assigning float as sum of two other floats in Xcode?

Leave a Comment