protected override void OnAppearing()
        {
            base.OnAppearing();

            if (!App.IsLoggedIn && !App.CancelledLogin) {
                var adLoginPage = new ADLoginPage();
                adLoginPage.Disappearing += (object sender, EventArgs e) => {
                    if (Device.OS == TargetPlatform.Android) {
                        // Work-around: OnAppearing called on PopModal only on iOS
                        // Thus we call in manually on Android
                        // http://forums.xamarin.com/discussion/18781/ios-and-android-different-behaviors-for-onappearing
                        this.OnAppearing();
                    }
                };
                Navigation.PushModalAsync(adLoginPage);
            } else {
                this.label.Text = App.IsLoggedIn ? "Welcome logged in user!" : "Your are not logged in.";
            }
        }
        protected override void OnAppearing()
        {
            base.OnAppearing();

            if (!App.IsLoggedIn && !App.CancelledLogin)
            {
                var adLoginPage = new ADLoginPage();
                adLoginPage.Disappearing += (object sender, EventArgs e) => {
                    if (Device.OS == TargetPlatform.Android)
                    {
                        // Work-around: OnAppearing called on PopModal only on iOS
                        // Thus we call in manually on Android
                        // http://forums.xamarin.com/discussion/18781/ios-and-android-different-behaviors-for-onappearing
                        this.OnAppearing();
                    }
                };
                Navigation.PushModalAsync(adLoginPage);
            }
            else
            {
                this.label.Text = App.IsLoggedIn ? "Welcome logged in user!" : "Your are not logged in.";
            }
        }