关于init方法的一个注记

Posted 2021-02-24

Here is a breakdown of creating a custom initializer and or general rules of init

In summary, this is what an init method needs to do:
 
- Call [super init] and assign the result to self.
- Check whether self is nil. If so, then exit this method right away and return nil to the caller.
 
- If self was not nil, do additional initialization if necessary. Usually this means you give properties and instance variables their initial values. By default, objects are nil, ints are 0 and BOOLs are NO. If you want to give these variables different initial values, then this is the place to do so.
- Return self to the caller.
 
You don’t always need to provide an init method. If your init method doesn’t need to do anything — if there are no properties or instance variables to fill in — then you can leave it out completely and the compiler will provide one for you.