Objective-C ARC: strong vs retain and weak vs assign

Question

There are two new memory management attributes for properties introduced by ARC, strong and weak.

Apart from copy, which is ob

Answer 1

Strong:

• Property will not Destroy but Only once you set the property to nil will the object get destroyed
• By default all instance variables and local variables are strong pointers.
• You use strong only if you need to retain the object.
• We generally use strong for UIViewControllers (UI item's parents)
• IOS 4 (non-ARC) We Can Use Retain KeyWord
• IOS 5(ARC) We Can Use Strong Keyword

Example: @property (strong, nonatomic) ViewController *viewController;

@synthesize viewController;

Weak

By Default automatically get and set to nil

• We generally use weak for IBOutlets (UIViewController's Childs) and delegate
• the same thing as assign, no retain or release

Example : @property (weak, nonatomic) IBOutlet UIButton *myButton;

@synthesize myButton;