iOS layout; I'm not getting it

Question

Well, "not getting it" is too harsh; I've got it working in for what for me is a logical setup, but it does not seem to be what iOS deems logical. So I'm not getting something.

Suppose I've got an app that shows two pieces of information; a date and a table. According to the MVC approach I've got three MVC at work here, one for the date, one for the table and one that takes both these MCVs and makes it into a screen, wiring them up.

The master MVC knows how/where it wants to layout the two sub MVC's. Each detail MVC only takes care of its own childeren within the bounds that were specified by the master MVC. Something like:

- (void)loadView {
    MVC* mvc1 = [[MVC1 alloc] initwithFrame:...]
    [self.view addSubview:mvc1.view];

    MVC* mvc2 = [[MVC2 alloc] initwithFrame:...]
    [self.view addSubview:mvc2.view];
}

If the above is logical (which is it for me) then I would expect any MVC class to have a constructor "initWithFrame". But an MVC does not, only view have this.

Why?

How would one correctly layout nested MVCs? (Naturally I do not have just these two, but the detail MVCs have sub MVCs again.)

---

Thanks all for replying. I will study the links that were provided.

Let me try to explain my issue one more time, hopefully to making it more clear. Do note that I already figured out that my view does not match iOS's, since I do not like where my code is going.

Yes, I'm calling a UIViewController an "MVC", since it for me at the moment implements all aspects of a MVC; it has controller code and an embedded view, plus the controller usually also holds and provides the data (all TableView examples implement it like this).

MVC can be present on many levels; basically a UITextField could (should?) be a MVC; there is a view, but also controller logic involved that you do not want to mix with other code. Encapsulation. For example: Java's Swing JTextField has a MVC. So does a JTable, JList, ... Multiple MVC patterns nested in other MVC's to build a whole screen.

This what I expect when some platform says it uses the MVC pattern. So When I coded the table, I created a MVC and only send the loadData message with a date as the parameter to it. It needs to take care of the rest itself. I have a Detail MVC that can slide in; I then tell it the object it needs to show and it needs to take care of the rest itself. Encapsulation.

So I have a lot of UIViewControllers with embedded UIViews. And that is not the way to do it...

Answer 1

One more potential link is the great talk from WWDC 2010 on MVC.

http://developer.apple.com/videos/wwdc/2010/

It is Session 116 - Model-View-Controllr for iPhone OS

The session is chock full of practical advice on how MVC really works, what makes it tick, why it's good. But it also has a lot of intro stuff to help folks new to the concept to wrap their heads around it.

If I understand your sentence on Java's Swing classes above are you talking about the anonymous classes that respond to events? If so those are not "MVC's", they are what is termed 'Observers', when they observe an event from the view they take some action (usually send a message to a controller). Cocoa Touch uses the Target/Action paradigm (and delegation) to achieve this.

I'd also strongly suggest you take Matthew and Stephen's advice and write a bunch of code. If you don't build that base of intuition, asking the right question (which is most of what is needed to get a good answer) is very difficult.

I really think the WWDC 2010 talk will help.

Good Luck!