Property vs. ivar in times of ARC

by

If a variable:

  1. Is declared in a class using ARC.
  2. Is used solely for class implementation (not exposed as part of the class interface).
  3. Does not require any KVO.
  4. Does not require any custom getter/setter.

Then it is appropriate to declare it as an ivar without a corresponding @property/@synthesize, and to refer to it directly within the implementation. It is inline with Encapsulation to declare this ivar in the class implementation file. 

// MyClass.h
@interface MyClass : ParentClass
@end

// MyClass.m
@implementation MyClass {
    NSString *myString;
}

- (void)myMethod {
    myString = @"I'm setting my ivar directly";
}
@end
  • This ivar will be treated as __strong by the ARC compiler.
  • It will be initialized to nil if it is an object, or 0 if it is a primitive.

More Related Contents:

  1. @property definitions with ARC: strong or retain?
  2. Reason to use ivars vs properties in objective c
  3. Why is @autoreleasepool still needed with ARC?
  4. How do I avoid capturing self in blocks when implementing an API?
  5. Get an object properties list in Objective-C
  6. Initializing a property, dot notation
  7. Why would you use an ivar?
  8. Disable Automatic Reference Counting for Some Files
  9. Handling Pointer-to-Pointer Ownership Issues in ARC
  10. ARC and bridged cast
  11. What is the difference between ivars and properties in Objective-C
  12. Is there any reason to declare ivars if you’re using properties exclusively in Objective-C?
  13. AVAudioPlayer not playing any sound
  14. Does ARC work with Core Graphics objects?
  15. With ARC, what’s better: alloc or autorelease initializers?
  16. Instance variables declared in ObjC implementation file
  17. Retain Cycle in ARC
  18. When should I use @synthesize explicitly?
  19. When converting a project to use ARC what does “switch case is in protected scope” mean?
  20. Zeroing Weak References in ARC
  21. AVAudioPlayer stops playing immediately with ARC
  22. Custom dealloc and ARC (Objective-C)
  23. Why does ARC retain method arguments?
  24. NSError and __autoreleasing
  25. Property ” not found on object of type ‘id’
  26. Does a private @property create an @private instance variable?
  27. Why can’t I release an object anymore? [duplicate]
  28. fake va_list in ARC
  29. Why do I need to write @synthesize when I provide getter and setter?
  30. Objective-C Difference between setting nil and releasing

Leave a Comment