Benefits when using static init in Objective C?

Question

Recently I've discovered webrtc-ios example from Github. While I was browsing though the project I noticed that VideoView class uses static method and I'm not sure is that necessary or not. VideoView is subclass of UIView and it overrides two init methods, initWithFrame: and initWithCoder:. I know it's normal to override those init methods and then use some method for setting up other stuff, like - (void)setup;.

But VideoView class uses static function, static void init(VideoView *self). Question is are there benefits when using static function vs. normal ObjC method?

Code in VideoView class looks like this:

-(id)initWithFrame:(CGRect)frame {

     if (self = [super initWithFrame:frame]) {
         init(self);
     }
     return self; 
}

-(id)initWithCoder:(NSCoder *)aDecoder {

     if (self = [super initWithCoder:aDecoder]) {
         init(self);
     }
     return self; 
}

 static void init(VideoView *self) { ... }

Answer 1

One difference between using a static function and an Objective-C method is that the static function cannot be overriden in a subclass. If the common init code is done in a

- (void)setup;

method, and a subclass MyVideoView of VideoView happens to implement a method with the same name, then

[[MyVideoView alloc] initWithFrame:..]

will call the subclass implementation, which might not be wanted.

In your code, initWithFrame/initWithCoder will always call the local init() function, even if an instance of a subclass is initialized.

If the common initialization is done in a method, then the method name should be more specific, to avoid that it is overriden "accidentally", for example

-(void)commonVideoViewSetup;