title: Xamarin Portable OnAppearing() XAML page loading
body: <p>i am using the Xamarin Forms Portable project and i am using the MVVM method. Right now I am stuck. I want to build a LOADING page. So when the (Custom) Page starts it must load a XAML page loading and when the Loading (call to a webservice) is done the XAML page loading must be set to visible = false. </p>
  
  <p>I have the next code that wont work:</p>
  
  <pre><code>    protected override async void OnAppearing()
      {
  
          base.OnAppearing();
  
          var page = Navigation.PushAsync(new ActivityIndicatorPage());
  
          await Task.Delay(1000);
  
          BindingContext = new ProductViewModel(_ProductId);
  
      }
  </code></pre>
  
  <p>So how do i Call the 'ActivityIndicatorPage' Page and then set it to invisible after the 'BindingContext = new ProductViewModel(_ProductId);' call is done. </p>
  
  <p>Thanx. </p>