Xamarin Forms Tabbed Page Trigger properties not working - xaml

Question

I'm trying to follow this sample
by using font awesome as icon for the tabbed page and use the triggers to change font color
but when I want to apply the style using font awesome I got an error that Property="IsChecked" does not exist for the target.
I noticed in the sample they are using shells how could I replicate that example using regular tabbed pages?
on the app.XAML I have the following
<OnPlatform x:TypeArguments="x:String"
x:Key="FontAwesomeSolid">
<On Platform="Android"
Value="Font5Solid.otf#Regular" />
<On Platform="iOS"
Value="FontAwesome5Free-Solid" />
</OnPlatform>
<OnPlatform x:TypeArguments="x:String"
x:Key="FontAwesomeRegular">
<On Platform="Android"
Value="Font5Regular.otf#Regular" />
<On Platform="iOS"
Value="FontAwesome5Free-Regular" />
</OnPlatform>
For the tabbed page I have the following
<?xml version="1.0" encoding="utf-8"?>
<TabbedPage x:Name="Tab" xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="pages.Views.HomeTabbedPage">
<!--Pages can be added as references or inline-->
<TabbedPage.Resources>
<ResourceDictionary>
<Style TargetType="Tab" x:Key="FollowTab">
<Style.Triggers>
<Trigger TargetType="TabbedPage"
Property="IsChecked" Value="False">
<Setter Property="Icon" >
<Setter.Value>
<FontImageSource FontFamily="{StaticResource FontAwesomeRegular}" Glyph=""/>
</Setter.Value>
</Setter>
</Trigger>
<Trigger TargetType="Tab"
Property="IsChecked" Value="True">
<Setter Property="Icon" >
<Setter.Value>
<FontImageSource FontFamily="{StaticResource FontAwesomeSolid}" Glyph=""/>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</ResourceDictionary>
</TabbedPage.Resources>
<ContentPage Title="sample page" />
</TabbedPage>

Answer 1

To replicate that in a normal TabbedPage you can try these steps:
1 - Create a converter to check TabbedPage.CurrentPage type:
public class SelectedTabTypeConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value == null)
return null;
if (!(value is Page))
throw new ArgumentException("Expected value to be of type " + nameof(Page), nameof(value));
// if value is a NavigationPage check against its RootPage
if (value is NavigationPage navPage)
return navPage.RootPage?.GetType();
return value.GetType();
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
=> throw new NotImplementedException();
}
2 - Add the x:Name attribute to the TabbedPage so we can reference it latter:
<TabbedPage x:Name="MyTabbedPage" ...
3 - Add the converter resource to TabbedPage.Resources:
<TabbedPage.Resources>
<ResourceDictionary>
<converters:SelectedTabTypeConverter x:Key="SelectedTabTypeConverter" />
</ResourceDictionary>
</TabbedPage.Resources>
4 - Add the pages and the DataTriggers:
<TabbedPage.Children>
<!-- Normal page tab default values -->
<views:OnePage Title="Page1">
<views:OnePage.Triggers>
<DataTrigger
TargetType="views:OnePage"
Binding="{Binding Source={x:Reference MyTabbedPage}, Path=CurrentPage, Converter={StaticResource SelectedTabTypeConverter}}"
Value="{x:Type views:OnePage}">
<Setter Property="Title" Value="Page1 Selected" />
</DataTrigger>
</views:OnePage.Triggers>
</views:OnePage>
<!-- NavigationPage tab -->
<NavigationPage Title="Page2">
<x:Arguments>
<views:TwoPage />
</x:Arguments>
<NavigationPage.Triggers>
<DataTrigger
TargetType="NavigationPage"
Binding="{Binding Source={x:Reference MyTabbedPage}, Path=CurrentPage, Converter={StaticResource SelectedTabTypeConverter}}"
Value="{x:Type views:TwoPage}">
<Setter Property="Title" Value="Page2 Selected" />
</DataTrigger>
</NavigationPage.Triggers>
</NavigationPage>
</TabbedPage.Children>