Add Shell Navigation templates for various pages Xamarin.Forms Shell - xamarin

Question

I have multi-page app, which has preLogin section and postLogin section.
Which is the best approach to make shell templates for these two sections?
preLogin pages doesnt have backbutton in navigationBar. I tried in xaml page NavigationPage.HasNavigationBar="false" (not AppShell.xaml, either in my page xaml) as well as in code behind NavigationPage.SetHasNavigationBar(this, false);
example xaml page which regardless on my NavigationPage.HasBackButton="false"
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:customViewEntry="clr-namespace:App.CustomViews.Entries"
xmlns:header="clr-namespace:App.CustomViews.CustomHeaders"
mc:Ignorable="d"
x:Class="App.Views.Login.EnterEmailAndPasswordPage"
NavigationPage.HasBackButton="false"
BackgroundImageSource="Login_Screen_Green.png">
<ContentPage.Content>
<StackLayout>
<header:HeaderWithTopRightIcon ImageUri="greenIcon.png"/>
<StackLayout VerticalOptions="EndAndExpand" Padding="0,50">
<customViewEntry:EvEntry
Placeholder="Enter your email"/>
<customViewEntry:EvEntry
Placeholder="Enter your password"
IsPassword="True"/>
<Button
Text="LOGIN"
Margin="25,0"
CornerRadius="7"
BackgroundColor="{StaticResource DarkGrayColor}"
TextColor="White"
Command="{Binding OpenEmailVerificationPageCommand}"/>
<Label
Padding="0,25,0,0"
Text="Don't have an account?"
FontSize="Small"
Style="{StaticResource WhiteSmallLabelStyle}"
HorizontalOptions="Center"
VerticalOptions="Start"/>
<Label
Text="SIGN UP"
TextDecorations="Underline"
FontSize="Small"
Style="{StaticResource WhiteSmallBoldLabelStyle}">
<Label.GestureRecognizers>
<TapGestureRecognizer Command="{Binding SignUpClickCommand}"/>
</Label.GestureRecognizers>
</Label>
</StackLayout>
</StackLayout>
</ContentPage.Content>
</ContentPage>
my AppShell looks like:
<?xml version="1.0" encoding="UTF-8"?>
<Shell xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:views="clr-namespace:App.Views"
xmlns:loginViews="clr-namespace:App.Views.Login"
x:Class="App.AppShell"
FlyoutBehavior="Disabled">
<!--Styles and Resources-->
<Shell.Resources>
<ResourceDictionary>
...removed due simplicity...
</ResourceDictionary>
</Shell.Resources>
<ShellContent ContentTemplate="{DataTemplate loginViews:EnterEmailPage}"/>
</Shell>
So, my questions are
1. How to dynamically hide back button on some pages and on some not? For navigation Im using await Shell.Current.GoToAsync(route)
2. Also I need a redirection when user leaves application, and again enter it based on elapsed time, to redirect to preLogin page (login) or to let him directly to postLogin (full access to the app) so I need maybe two AppShell classes, and to call it different shells OnResume() ?

Answer 1

How to dynamically hide back button on some pages and on some not? For navigation Im using await Shell.Current.GoToAsync(route)
About this question , here is a Workaround for you .
Shell application has Back button behavior to ovveride Back Button dynamically , even can Hide/Show it .
If using Shell.Current.GoToAsync(route) to navigate to destination page , you can follow the below code to use in your destination page.
// Button click to show Back Button
private void Button_Clicked_Show(object sender, EventArgs e)
{
Shell.SetBackButtonBehavior(this, new BackButtonBehavior
{
IsEnabled = true
});
}
// Button click to hide Back Button
private void Button_Clicked_Hide(object sender, EventArgs e)
{
Shell.SetBackButtonBehavior(this, new BackButtonBehavior
{
IconOverride = "null.png", // null.png not exists in project ,just want
the program to show a blank Back button
IsEnabled = false
});
}
I will show the effect with a Gif :
Also I need a redirection when user leaves application, and again enter it based on elapsed time, to redirect to preLogin page (login) or to let him directly to postLogin (full access to the app) so I need maybe two AppShell classes, and to call it different shells OnResume() ?
About this question , here is a Suggestion for you , you can conside that whether fit your needs .
You can use Navigation.PushModalAsync(new LoginPage()) to redirect to preLogin page based on elapsed time . Otherwise using Shell.Current.GoToAsync(route) to Navigate . You can deal with them in OnResume Method .
For example as follow :
protected override void OnResume()
{
if(time > xxx)
{
Navigation.PushModalAsync(new LoginPage());
}
else
{
Shell.Current.GoToAsync(route);
}
}
Here using PushModalAsyncto Login Page that is a Model Page . After using Navigation.PopModalAsync() can dismiss LoginPage and redirect to other Page with Shell.Current.GoToAsync(route).