如何使用 Singleton 来允许各种视图控制器之间的通信？

Question

I have been suggested to use the Singleton model at:

http://www.galloway.me.uk/tutorials/singleton-classes/

Some of the questions I have are:

where do I declare the singleton? Do I release it anywhere or does it terminate with the application? Any tips in terms of the Singletons in apps?

Thanks

Answer 1

It is just a class having only one object. That's why its called singleton.

We don't release it. It gets when the app terminates.

Answer 2

Singleton object can be accessed from any where in your application.

You initialize it at the first time get call (via static method). Then the instance will remain in the memory.

You releases it when the application terminated.

Answer 3

A Singleton is a construct allowing a class to be instantiated only once.

I am not an expert in iPhone programming, but Singleton doesn't mean the object is accessible from anywhere in your application imho. You can still manage it's accessiblity through visibility. And you definitely should.

Overuse of the Singleton can lead to tight coupling of your classes to a static instance (your Singleton) and that is usually what you are trying to avoid in object oriented programming.