The app crashes with SimpleShell

[radekvym]

The app crashes with SimpleShell

[RadekVyM]

Hi @ziomek64,

thanks for informing me about the issue. Where exactly do you call SimpleToolkit.SimpleShell.SimpleShell.Current.GoToAsync($"//main");? Does the app crash even if this call is commented out?

[ziomek64]

It happens in OnAppearing for my login page. The app doesn't crash when its commented or with normal shell

protected override async void OnAppearing()
{
    var token = Preferences.Get("token", "default_value");
    bool validation = true;

    try
    {
        validation = false;
        if (token != "default_value")
        {
            IJsonSerializer serializer = new JsonNetSerializer();
            var provider = new UtcDateTimeProvider();
            IJwtValidator validator = new JwtValidator(serializer, provider);
            IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
            IJwtAlgorithm algorithm = new HMACSHA256Algorithm(); // symmetric
            IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder, algorithm);

            //TODO decoding z login taska i sprawdzanie expiry w ten sposob
            //var json = decoder.Decode(token);

            validation = true;
        }
    }
    catch (TokenExpiredException)
    {
        Preferences.Set("token", "default_value");
    }
    catch (SignatureVerificationException)
    {
        Preferences.Set("token", "default_value");
    }
    catch (InvalidTokenPartsException)
    {
        Preferences.Set("token", "default_value");
    }
    catch (HttpRequestException httpRequestException)
    {
        Debug.WriteLine(httpRequestException.Message);
        MainThread.BeginInvokeOnMainThread(() =>
        {
            var toast = Toast.Make("No internet.", duration, fontSize);

            toast.Show(cancellationTokenSource.Token);
        });
    }
    catch (Exception e)
    {
        Debug.WriteLine(e);
        if (e.Message.Contains("Unable to resolve host"))
        {
            MainThread.BeginInvokeOnMainThread(() =>
            {
                //DependencyService.Get<Toast>().Show("Unexpected error happened");

                var toast = Toast.Make("No internet.", duration, fontSize);

                toast.Show(cancellationTokenSource.Token);
            });
        }
        else
        {
            MainThread.BeginInvokeOnMainThread(() =>
            {
                //DependencyService.Get<Toast>().Show("Unexpected error happened");

                var toast = Toast.Make("Unexpected error happened.", duration, fontSize);

                toast.Show(cancellationTokenSource.Token);
            });
        }
    }
    finally
    {
        if (validation)
        {
            await SimpleToolkit.SimpleShell.SimpleShell.Current.GoToAsync($"//main");
        }
    }
}

Should simple shell be installed in platform specific projects too or not?

[RadekVyM]

Hi @ziomek64,

I have finally tried to take a look at this issue. However, I probably will not be able to fix it because of the way how creating a handler for a ShellItem works.

A workaround to this issue is to delay the navigation using Task.Delay() a bit:

await Task.Delay(100);
await Shell.Current.GoToAsync($"//main");

The delay is needed only on the first navigation to the initial page. On subsequent navigations to that page and on other pages it should not be needed.

And by the way, I currently do not plan to continue developing the SimpleToolkit.SimpleShell.Controls package, so I do not recommend using that.