A common base page for using IsBusy property to show a busy indicator.

BaseContentPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="LoadingPage"
             x:Name="ContentPage">
    <ContentPage.Content>
        <AbsoluteLayout>
            <ContentView Content="{Binding Source={x:Reference ContentPage},Path=MainContent}"
                         HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" 
                         AbsoluteLayout.LayoutBounds="0,0,1,1" AbsoluteLayout.LayoutFlags="All">
            </ContentView>
            <!-- Your Busy Indicator (Check out syncfusion's busy indicator) -->
            <ContentView Content="{Binding Source={x:Reference ContentPage}, Path=LoadingView}" 
                         IsVisible="{Binding Source={x:Reference ContentPage},Path=IsBusy}" 
                                    AbsoluteLayout.LayoutBounds="0,0,1,1" AbsoluteLayout.LayoutFlags="All" />
        </AbsoluteLayout>
    </ContentPage.Content>
</ContentPage>

BaseContentPage.xaml.cs

[ContentProperty(nameof(MainContent))]
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class LoadingPage : ContentPage
{
    public LoadingPage()
    {
        InitializeComponent();
    }

    public static readonly BindableProperty MainContentProperty =
        BindableProperty.Create(nameof(MainContent), typeof(View), typeof(LoadingPage));

    public static readonly BindableProperty LoadingContentProperty =
        BindableProperty.Create(nameof(LoadingView), typeof(View), typeof(LoadingPage));

    public View LoadingView
    {
        get => (View) GetValue(LoadingContentProperty);
        set => SetValue(LoadingContentProperty, value);
    }

    public View MainContent
    {
        get { return (View) GetValue(MainContentProperty); }
        set { SetValue(MainContentProperty, value); }
    }

    protected override void OnBindingContextChanged()
    {
        base.OnBindingContextChanged();
        if (MainContent == null)
        {
            return;
        }
        SetInheritedBindingContext(MainContent, BindingContext);
    }
}

Hi @QiMata
How do you use this base page? Can you share usage of this LoadingPage?
Thanks.

The other pages in the application would inherit from BaseContentPage instead of Content page.

Instead of inheriting from BasePage we can also create a controltemplate like shown here http://surfy57.free.fr/?p=42