Overlay a layout on an application outside of the main application.

Hi,

Is it possible to inflate a view or dialog box on top of an application that is not the main application? For example: My current app triggers whenever an outgoing phone call is attempted. Is there a way for my secondary layout to appear on top of the android call/dialing application layout when triggered?

I'm currently using this dialog and when I switch to my original activity I can see that the dialog box is displayed. Ideally I would like for it to appear on top of the application that is currently active. (the call/phone apk)

                    if (filter.GetAction(0) == Intent.ActionNewOutgoingCall)
                    {
                        PopupWindow popup = new PopupWindow();
                        View customView = LayoutInflater.Inflate (Resource.Layout.Selection,null);

                        AlertDialog.Builder builder = new AlertDialog.Builder (this);
                        builder.SetView(customView);

                        builder.Create ();
                        builder.Show ();
                        //popup.ShowAtLocation(ro, GravityFlags.Left, 1, 1);
                    }