Interface Implement differences in C# vs Java

Question

I have created a binding for a java library that comes as part of an SDK for a scanner, model Honeywell Dolphin CT50. However, I have run into a bit of rut in my understanding.

The following example is given in Java. The Create method expects a interface implementation. However, i am not aware of a similar way to override the 'onCreated' method of the interface while still accessing the class-wide variables. This is were i am having the trouble, how can i do the following in C#.

Java:

private static BarcodeReader barcodeReader;
private AidcManager manager;

public void onCreate(Bundle savedInstanceState) {
    // create the AidcManager providing a Context and a
    // CreatedCallback implementation.
    AidcManager.create(this, new CreatedCallback() {
        @Override
        public void onCreated(AidcManager aidcManager) {
            manager = aidcManager;
            barcodeReader = manager.createBarcodeReader();
        }
    });

}

In .NET, the compiler will not do as above and implement the interface as an anonymous type, thus I have to implement the interface. However, how can i then assign the class wide variables?

My C#:

NameSpace Scanner {
    private static BarcodeReader barcodeReader;
    private AidcManager manager;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);

       CreateCallback callback = new CreateCallback() {  };
       AidcManager.Create(this, callback.OnCreated(AidcManager aidcManager));
    }

public class CreateCallback : AidcManager.ICreatedCallback
{
    public IntPtr Handle
    {
        get
        {
            throw new NotImplementedException();
        }
    }
    public void Dispose()
    {
        throw new NotImplementedException();
    }
    public void OnCreated(AidcManager p0)
    {
        // How can I initialize the manager and barcode reader variables in the class above from here?
    }
  }
}

Answer 1

You can create a callback implementation CreateCallback that has a other callback as constructor parameter successAction. This passed callback OnManagerCreated will be called in the OnCreated of CreateCallback.

Important Note: If you implement a Java interface, you have to inherit from Java.Lang.Object. Do not implement Handle and Dispose() on your own.

Activity

public class MyActivity : Activity 
{
    private static BarcodeReader _barcodeReader;
    private AidcManager _manager;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);

        CreateCallback callback = new CreateCallback(OnManagerCreated) {  };
        AidcManager.Create(this, callback);
    }

    private void OnManagerCreated(AidcManager manager)
    {
        _manager = manager;
        _barcodeReader = manager.CreateBarcodeReader();
    }
}

Callback implementation

public class CreateCallback : Java.Lang.Object, AidcManager.ICreatedCallback
{
    private Action<AidcManager> _successAction;
    public CreateCallback(Action<AidcManager> successAction)
    {
        _successAction = successAction;
    }

    public void OnCreated(AidcManager p0)
    {
        _successAction(p0);
    }
}

Other possibility

You can also implement the interface directly in your activity class like

public class MyActivity : Activity, AidcManager.ICreatedCallback 
{
    // ...
}