Question

I have a view in a MonoTouch app using MvvmCross framework that I would like displayed Modal (NavigationController.PresentModalViewController).

Answer 1

MvvmCross starts from the premise that all ViewModels are just “normal pages” – so in iOS/MonoTouch that means UIViewControllers presented using a UINavigationController.

To move away from this premise – towards tabbed displays, modal displays, split controllers, popups, etc – then you can adjust the Presenter logic within your MonoTouch app.

The presenter’s job is to implement:

public interface IMvxTouchViewPresenter
{
    void Show(MvxShowViewModelRequest view);
    void Close(IMvxViewModel viewModel);
    void CloseModalViewController();
    void ClearBackStack();
    bool PresentModalViewController(UIViewController controller, bool animated);
    void NativeModalViewControllerDisappearedOnItsOwn();
}

The presenter used for your app is selected in AppDelegate construction – e.g. see how the TwitterSearch builds different presenters for iPhone and iPad.

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Fortunately, for simple Modal support, one of the standard presenters available is MvxModalSupportTouchViewPresenter.cs

This presenter looks to see if the view being presented has the IMvxModalTouchView marker interface – it tests view is IMvxModalTouchView. If this interface is present, then it uses modal presentation for the view instead of “normal navigation”.

To use this, change your AppDelegate code to something:

    public override bool FinishedLaunching(UIApplication app, NSDictionary options)
    {
        window = new UIWindow(UIScreen.MainScreen.Bounds);

        // initialize app for single screen iPhone display
        var presenter = new MvxModalSupportTouchViewPresenter(this, window);
        var setup = new Setup(this, presenter);
        setup.Initialize();

        // start the app
        var start = this.GetService<IMvxStartNavigation>();
        start.Start();

        window.MakeKeyAndVisible();

        return true;
    } 

Then add the marker interface to your modal View(s):

 public class MyView : MvxBindingTouchViewController<MyViewModel>, IMvxModalTouchView
 {
      // ....
 }