How to receive application wide events with multiview application

Question

Hello,

I am developing an iPhone application with multiviews (Nav controller), but i like to receive an event if user touches in any view of the view. I understand it can be done by subclassing application delegate? If that's true how can i do it? My requirement is, i like to receive an event as soon as user touches any where in any view within my application.

Thanks for your help and time.

Answer 1

A way to do it is to use a Singleton class (which acts as an observer/mediator), which the application is an example of, in which you have viewControllers subscribe to when they are intersted in the touch events of a certain view. When the touch occurs the Singleton class is informed of the event as a result it informs all subscribers to the event of the event. Here is an example

   @interface MyEventClass
  {

  -(void)TouchEventDidOccur; 
  -(void)subscribeToTouchEvent:(id)delegate selector(selector):sel
  }

Above is the singleton class

now this is an example of what the view touchesBegan method might look like

-(void)touchesBegan...
{
    [[MyEventClass sharedInstance] TouchEventDidOccur];
}

and how one would subscribe to the event

 [[MyEventClass sharedInstance] subscribeToTouchEvent:self selector:@selector(receiveTouchEvent:)]

hope this helps

Answer 2

Your reference to subclassing UIApplication will work. Read down through the comments and it covers a somewhat quirky IMO way to implement it (by having the AppDelegate be a subclass of UIApplication). Myself, I would create a separate class to be the UIApplication subclass, rather than having the app delegate do both jobs, but I see the merit of either way.

That said, this is a very large and unusual stick and may suggest a design failure. What problem are you solving with this?

Answer 3

What's wrong with using notifications? If you have disconnected classes across your application, it's trivial to have them listen for a particular notification, then have your views or view controllers post that notification when a touch event happens. All of the observers will take action on the notification.