Question

In followup to Where has "window-based" project gone?, what are the steps needed to modify an empty application to a window-based application in MonoTouch using Xcode 4.2?

I am learning iOS development and have read about 1 1/2 books (most recently, “iOS Programming: The Big Nerd Ranch Guide (2nd Edition)” — nice book). I found instructions here on converting an empty application to a window-based application for Objective-C.

I tried applying these steps to a sample MonoTouch application and I get run-time errors related to needing a root view controller.

Is there a site that lists the steps in small words for simple minds?

Answer 1

Here are the steps I discovered by downloading a window-based application sample from the source code of one of my Monotouch books (http://www.apress.com/9781430231745) and then creating an empty solution. I compared the files and added the things needed to the empty one to make it look (and act) like the window-based one.

• Change the line UIApplication.Main (args, null, "AppDelegate"); in Main to UIApplication.Main (args);.

• Add an AppDelegate-derived class to the file Main.cs (inside the namespace):

    // The name AppDelegate is referenced in the MainWindow.xib file.
    public partial class AppDelegate : UIApplicationDelegate
    {
        // This method is invoked when the application has loaded its UI and its ready to run
        public override bool FinishedLaunching (UIApplication app, NSDictionary options)
        {
            // If you have defined a view, add it here:
            // window.AddSubview (navigationController.View);

            window.MakeKeyAndVisible ();

            return true;
        }
    }

• Remove the file AppDelegate.cs (delete it from the project).

• Add a new Empty iPhone Interface Definition file and name it MainWindow.xib.

• Add a new empty C# file and name it MainWindow.xib.designer.cs. Insert the following code:

    using MonoTouch.Foundation;

    namespace MY_NAMESPACE
    {
        [Register ("AppDelegate")]
        partial class AppDelegate
        {
            [Outlet]
            MonoTouch.UIKit.UIWindow window { get; set; }

            void ReleaseDesignerOutlets ()
            {
                if (window != null) {
                    window.Dispose ();
                    window = null;
                }
            }
        }
    }

• Change MY_NAMESPACE to your namespace.

• Open MainWindow.xib in the Interface Builder (Xcode 4.2).

• Change the class for the File’s Owner to UIApplication (third tab – Identity Inspector).

• Add a new Object object (search for object in the widgets list) and change the class to AppDelegate.

• Add a new Window object.

• Select the File’s Owner, click the last tab in the inspectors (Connections Inspector) and connect the delegate link to the App Delegate.

• Select the App Delegate and connect the window link to your new window.

• Save the MainWindow.xib file changes in Interface Builder.

• Return to MonoDevelop.

• Open the file Info.plist and change the Main Interface to MainWindow.

I’m getting a warning about Applications are expected to have a root view controller at the end of application launch, but the application seems to run. I suspect that the warning is coming from some difference in the .xib file. Perhaps the Xcode 3.2 version includes some indication that this is the root view controller. How do I get rid of this warning?