Why/when do we have to call super.ViewDidLoad?

Question

Everyone tells me \"Use super.viewDidLoad() because it\'s just like that\" or \"I\'ve been doing it always like that, so keep it\", \"It\'s wrong if you don\'t call super\",

Answer 1

I think calling super.viewDidLoad() is, first of all, a good practice.

The usual thing in iOS is to do all of your subclass setups after the superclass has completed the setup that it needs to do (initializing properties, laying things out, etc.). If you don't give the superclass a chance to handle all of its setups before you start changing things around, it's possible you'll encounter some strange bugs and behavior.

We can draw a parallel with Class Initialization: "A designated initializer must delegate up to a superclass initializer before assigning a value to an inherited property." We're doing this to be sure that all superclass properties have a value and based on that fact we could safely use them through inheritance in our subclass.

Rule of thumb:

• When initializing/setting up, run the superclass' implementations first.
• When tearing down/cleaning up, run the superclass' implementation last.

Assuming that viewDidLoad() is some sort of initialization we should call super.viewDidLoad() first to correctly set things up in the superclass.

If we check the implementation of viewDidLoad() in UIViewController base class, we can see that it's empty. So maybe the only one reason to calling super.viewDidLoad() from you child class is a good coding style :-) Lets follow it!