Monotouch: UINavigationController, override initWi

问题:

How is it possible to override the constructor for UINavigationController for passing in a rootViewController?

I would have a method like the following in Objective-C:

-(id)initWithRootViewController:(UIViewController*)rootViewController
{
    UIViewController *fakeController = [[[UIViewController alloc] init] autorelease];
    if (self = [super initWithRootViewController:fakeController]) {

      self.fakeRootViewController = fakeController;

      rootViewController.navigationItem.hidesBackButton = YES;

      [self pushViewController:rootViewController animated:NO];
    } 
    return self;
}

Thank you in advance. Regards.

P.S This snippet of code has been taken from Change the root view controller

EDIT:

Thank you for your replies. I was interested in the previous snippet of code because it's particular interesting.

@Geoff Norton: Maybe I'll never use your solution but I find it amazing anyway...

My attempt is to create a sort of UINavigationViewController that acts as a template. In particular, the UINavigationController initially has a loginView (it could be a sort of rootviewcontroller). Then when logging in, I could have two type of views: main and secondary views. The former are at the same level of the login view (they could be a sort of rootviewcontrollers). The latter are pushed above the first ones. You can navigate through the normal UInavigationController stack or by means of a toolbar. The toolbar loads only main view.

Is it possible to do this with a UINavigationController?

Thank you again. Regards.

回答1:

Its possible but you shouldn't do it. According to Apple the UINavigationController is "not designed for subclassing". If you insist on doing this:

public YourNavController : UINavigationController {
    [Export ("initWithRootViewController:")]
    public YourNavController (UIViewController vc) {
      UIViewController fc = new UIViewController ();
      Handle = Messaging.intptr_objc_msgSend_intptr (this.Handle, Selector.GetHandle ("initWithRootViewController:"), fc.Handle);
      FakeRootViewController = fc;
      vc.NavigationItem.HidesBackButton = true;
      PushViewController (vc, false);
    }
}

Something close to that should work.

回答2:

Like Geoff Norton pointed out, you are not supposed to subclass UINavigationController.

I have insisted on doing this myself a few times, just to find out that there are bugs that pop up every once in a while that have no logical explanation. When you Google those up, the answer invariably is "You should have not subclassed UINavigationController".