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So searching around Stack Overflow this seems to be how to make private variables in Objective-C:
@interface ClassName()
{
@private
NSArray* private;
}
@property (strong, nonatomic) NSArray* public;
@end
Now this is where I get confused. The property is declared as (strong, nonatomic), but the private variable has nothing of the sort. So how does arc know if it's strong or not?
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The instance variables are visible for all methods, constructors, and block in the class. Normally, it is recommended to make these variables private (access level). However, visibility for subclasses can be given for these variables with the use of access modifiers. Instance variables have default values.
Instance variables are made private to force the users of those class to use methods to access them. In most cases there are plain getters and setters but other methods might be used as well.
Variable Declaration in Objective-C You will use extern keyword to declare a variable at any place. Though you can declare a variable multiple times in your Objective-C program but it can be defined only once in a file, a function or a block of code.
The goal of the @property directive is to configure how an object can be exposed. If you intend to use a variable inside the class and do not need to expose it to outside classes, then you do not need to define a property for it. Properties are basically the accessor methods.
Instance variables are __strong by default.
From Apple's ARC Transition Guide, regarding variables (presumed to include instance variables):
__strong is the default
and later:
With ARC, instance variables are strong references by default—assigning an object to an instance variable directly does extend the lifetime of the object
This holds until the property is connected to the ivar via @synthesize. At this point, the ownership qualifier of the property takes precedence. However, if you declare a property as anything but strong, and then implement both the setters and getters by hand, you'll have to manually declare the backing ivar's ownership qualifier as well.
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