UIViewController as a singleton

问题

I have a UIViewController in a tab bar application. I've added the controller from the MainWindow.nib file (i.e. not programatically).

My question is how can I make my view controller a singleton? (To resolve the Facebook delegate issue).

回答1:

You probably want to make your "Facebook connection code" a singleton (or part of the app delegate), but not the view controller itself. Then just wire up the FB thing with any view controller that needs it.

回答2:

If you really want to create singletons (but I don't think you do, please rethink your design - what is "the facebook delegate problem" exactly?), look here in Apple's sample code

回答3:

You can make any class a singleton adding something like this to the .m file (and you also have to add declaration to the .h):

+ (id)sharedInstance {
  static id sharedInstance;
  @synchronized(self) {
    if (!sharedInstance)
      sharedInstance = [[ClassName alloc] init];
    return sharedInstance;
  }
}

来源：https://stackoverflow.com/questions/5781749/uiviewcontroller-as-a-singleton