Unable to find resource ID #0xffffffff when trying to move through AppShell

Question

I've tried and tried solutions I find online and none have worked so far.

I have a Xamarin app with a LogInPage and a LoggedInPage. On start I navigate to the LogInPage, hosted within a TabBar, so the FlyoutMenu is not visible, and when the user logs in correctly I try to move the Shell to the LoggedInPage, which is part of a FlyoutMenu.

However, the app crashes and it returns the following response:

Android.Content.Res.Resources+NotFoundException Message=Unable to find resource ID #0xffffffff

My code is as follows:

App

<Application xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="FinalProject.App">
    <Application.Resources>
        <ResourceDictionary>
            <Style TargetType="Button">
                <Setter Property="TextColor" Value="White"></Setter>
                <Setter Property="VisualStateManager.VisualStateGroups">
                    <VisualStateGroupList>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal">
                                <VisualState.Setters>
                                    <Setter Property="BackgroundColor" Value="DodgerBlue" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="Disabled">
                                <VisualState.Setters>
                                    <Setter Property="BackgroundColor" Value="Transparent" />
                                </VisualState.Setters>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateGroupList>
                </Setter>
            </Style>
        </ResourceDictionary>
    </Application.Resources>
</Application>

AppShell

<Shell x:Name="MainShell" xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="FinalProject.AppShell"
             Title="FinalProject"
             xmlns:core="clr-namespace:FinalProject"
             xmlns:coreviews="clr-namespace:FinalProject.Views">

    <Shell.Resources>
        <ResourceDictionary>
            <Style x:Key="BaseStyle" TargetType="Element">
                <Setter Property="Shell.BackgroundColor" Value="DodgerBlue" />
                <Setter Property="Shell.ForegroundColor" Value="White" />
                <Setter Property="Shell.TitleColor" Value="White" />
                <Setter Property="Shell.DisabledColor" Value="Transparent" />
                <Setter Property="Shell.UnselectedColor" Value="Transparent" />
                <Setter Property="Shell.TabBarBackgroundColor" Value="DodgerBlue" />
                <Setter Property="Shell.TabBarForegroundColor" Value="White"/>
                <Setter Property="Shell.TabBarUnselectedColor" Value="Transparent"/>
                <Setter Property="Shell.TabBarTitleColor" Value="White"/>
            </Style>
            <Style TargetType="TabBar" BasedOn="{StaticResource BaseStyle}" />
            <Style TargetType="FlyoutItem" BasedOn="{StaticResource BaseStyle}" />

            
            <Style Class="FlyoutItemLabelStyle" TargetType="Label">
                <Setter Property="TextColor" Value="White"></Setter>
            </Style>
            <Style Class="FlyoutItemLayoutStyle" TargetType="Layout" ApplyToDerivedTypes="True">
                <Setter Property="VisualStateManager.VisualStateGroups">
                    <VisualStateGroupList>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal">
                                <VisualState.Setters>
                                    <Setter Property="BackgroundColor" Value="{x:OnPlatform UWP=Transparent, iOS=White}" />
                                    <Setter TargetName="FlyoutItemLabel" Property="Label.TextColor" Value="DodgerBlue" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="Selected">
                                <VisualState.Setters>
                                    <Setter Property="BackgroundColor" Value="DodgerBlue" />
                                </VisualState.Setters>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateGroupList>
                </Setter>
            </Style>

            
            <Style Class="MenuItemLayoutStyle" TargetType="Layout" ApplyToDerivedTypes="True">
                <Setter Property="VisualStateManager.VisualStateGroups">
                    <VisualStateGroupList>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal">
                                <VisualState.Setters>
                                    <Setter TargetName="FlyoutItemLabel" Property="Label.TextColor" Value="DodgerBlue" />
                                </VisualState.Setters>
                            </VisualState>
                        </VisualStateGroup>
                    </VisualStateGroupList>
                </Setter>
            </Style>
        </ResourceDictionary>
    </Shell.Resources>

    <FlyoutItem Title="Main">
        <ShellContent Route="LoggedPage" ContentTemplate="{DataTemplate coreviews:LoggedPage}" />
    </FlyoutItem>
    <FlyoutItem Title="Trial">
        <ShellContent Route="TrialPage" ContentTemplate="{DataTemplate coreviews:TrialPage}" />
    </FlyoutItem>

   
    <MenuItem Text="Logout" StyleClass="MenuItemLayoutStyle" Clicked="Logout">
    </MenuItem>

    
    <TabBar>
        <ShellContent Route="LoginPage" ContentTemplate="{DataTemplate coreviews:LogInPage}" />
    </TabBar>

LogInPage.xaml:

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="FinalProject.Views.LogInPage"
             BackgroundColor="White">
    <ContentPage.Content>
        <StackLayout 
        VerticalOptions="Center"
        Margin="20">
            
            <Label
                Text="Caminante"
                HorizontalOptions="Center"
                TextColor="Black"
                FontSize="35"
                Margin="0, 20"
            />

            <Entry
                Placeholder="E-mail"
                PlaceholderColor="Black"
                TextColor="Black"
                Keyboard="Email"
                x:Name="EmailInput"
            />

            <Entry
                Placeholder="Password"
                PlaceholderColor="Black"
                TextColor="Black"
                IsPassword="true"
                x:Name="PasswordInput"
            />

            <Button
                Text="Enter"
                Clicked="LoginClicked"
                Margin="60, 40"
                BackgroundColor="DodgerBlue"
                TextColor="White"
            />

            <Button
                Text="Register"
                Clicked="RegisterClicked"
                Margin="60, 40"
                BackgroundColor="DodgerBlue"
                TextColor="White"
            />

        </StackLayout>
    </ContentPage.Content>
</ContentPage>

LogInPage.xaml.cs

using FinalProject.Services;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace FinalProject.Views
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class LogInPage : ContentPage
    {
        IAuth auth;

        public LogInPage()
        {
            InitializeComponent();

            auth = DependencyService.Get<IAuth>();

            //Routing
        }

        async void LoginClicked(object sender, EventArgs e)
        {
            string Token = await auth.LoginWithEmailPassword(EmailInput.Text, PasswordInput.Text);
            
            if (Token != "")
            {
                Storage.uid = Token;
                Storage.userEmail = EmailInput.Text;
                await Shell.Current.GoToAsync("///LoggedPage");
                //Application.Current.MainPage = new AppShell();
            }
            else
            {
                ShowError();
            }
        }

        async void RegisterClicked(object sender, EventArgs e)
        {
            await auth.RegisterWithEmailPassword(EmailInput.Text, PasswordInput.Text);
            string Token = await auth.LoginWithEmailPassword(EmailInput.Text, PasswordInput.Text);
            await FireBaseActions.AddUser(Token, EmailInput.Text);

            LoginClicked(sender, e);
        }


        async private void ShowError()
        {
            await DisplayAlert("Authentication Failed", "E-mail or password are incorrect. Try again!", "OK");
        }
    }
}

LoggedPage.xaml

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="FinalProject.Views.LoggedPage">
    <ContentPage.Content>
        <StackLayout x:Name="slLoggedIn1">
            <Label Text="Working?"/>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

LoggedPage.xaml.cs

namespace FinalProject.Views
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class LoggedPage : ContentPage
    {
        public string noChars { get; set; }
        public List<Character> lista { get; set; }
        public bool Visible { get; set; }
        public bool notVisible { get { return !Visible; } }
        public LoggedPage()
        {
            BindingContext = this;
            noChars = "Hello, " + Services.Storage.userEmail + "!" + Environment.NewLine + "It seems you don't have any characters yet, press the button below to fix that.";
            if (FireBaseActions.GetUserCharacters().Result.Count.Equals(0) || FireBaseActions.GetUserCharacters().Result.Equals(null))
            {
                lista = new List<Character>();
                Visible = false;
            }
            else
            {
                lista = FireBaseActions.GetUserCharacters().Result;
                Visible = true;
            }

            InitializeComponent();
        }

Edit: Added IAuth by a commenter's suggestion.

IAuth implementing class:

[assembly: Dependency(typeof(AuthDroid))]
namespace CaminanteFinal.Droid
{
    class AuthDroid : IAuth
    {
        public async Task<string> LoginWithEmailPassword(string email, string password)
        {
            try
            {
                var user = await FirebaseAuth.Instance.SignInWithEmailAndPasswordAsync(email, password);
                var token = await (FirebaseAuth.Instance.CurrentUser.GetIdToken(false).AsAsync<GetTokenResult>());
                //return FirebaseAuth.Instance.CurrentUser.Uid;
                return token.Token;
            }
            catch (FirebaseAuthInvalidUserException e)
            {
                Acr.UserDialogs.UserDialogs.Instance.Alert(e.ErrorCode, "Error", "Ok");
                e.PrintStackTrace();
                return "";
            }
            catch (FirebaseAuthInvalidCredentialsException e)
            {
                Acr.UserDialogs.UserDialogs.Instance.Alert(e.ErrorCode, "Error", "Ok");
                e.PrintStackTrace();
                return "";
            }
        }
        public async Task<string> RegisterWithEmailPassword(string email, string password)
        {
            try
            {
                var user = await FirebaseAuth.Instance.CreateUserWithEmailAndPasswordAsync(email, password);
                Acr.UserDialogs.UserDialogs.Instance.Alert("User " + email + " with password " + password + " has been created.", "Success!", "Ok");
                return "";
            }
            catch (FirebaseAuthUserCollisionException e)
            {
                Acr.UserDialogs.UserDialogs.Instance.Alert(e.ErrorCode, "Error", "Ok");
                e.PrintStackTrace();
                return "";
            }
            catch (FirebaseAuthWeakPasswordException e)
            {
                Acr.UserDialogs.UserDialogs.Instance.Alert(e.ErrorCode, "Error", "Ok");
                e.PrintStackTrace();
                return "";
            }
            catch (FirebaseAuthInvalidCredentialsException e)
            {
                Acr.UserDialogs.UserDialogs.Instance.Alert(e.ErrorCode, "Error", "Ok");
                e.PrintStackTrace();
                return "";
            }
        }
    }
}

Answer 1

This is an issue with Xamarin.Forms, which is already tracked on github.

You need to wait for next SR for XF5 when this PR is merged or rollback to XF 4.8