Xamarin Code Behind - Login Example - With ActivityIndicator

Login.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"
             xmlns:d="http://xamarin.com/schemas/2014/forms/design"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d"
             Shell.NavBarIsVisible="False"
             Title="Login"
             Visual="Material"
             BackgroundColor="{StaticResource StrongBGColor}"  
             x:Class="LoginExample.Login">
    <ContentPage.Content>
        <Grid>
            <StackLayout VerticalOptions="Center" Padding="30" Margin="10" Spacing="8">
                <Frame HeightRequest="180" Padding="0" CornerRadius="10" IsClippedToBounds="True" HorizontalOptions="CenterAndExpand" Margin="0,0,0,50">
                    <Image Source="LoginLogo.png"  />
                </Frame>
                <Label Text="Login" FontAttributes="Bold"/>
                <Entry Text="" x:Name="txtLogin" />
                <Label Text="Password" FontAttributes="Bold"/>
                <!-- Use Password type instead -->
                <Entry Text="" x:Name="txtPassword" />
                <Button Text="Login" WidthRequest="200" HorizontalOptions="Center" Margin="0,30,0,10" x:Name="btnLogin" Clicked="btnLogin_Clicked" />
            </StackLayout>

            <Frame Padding="10"
                   CornerRadius="35"
                   Margin="10"
                   Opacity="0.8"
                   IsVisible="True"
                   BackgroundColor="{StaticResource StrongBGColor}"
                   x:Name="ActivIndicator"
                   VerticalOptions="StartAndExpand"
                   HorizontalOptions="CenterAndExpand">
                <ActivityIndicator x:Name="actInd"
                                   HeightRequest="50"
                                   WidthRequest="50"
                                   IsRunning="True"
                                   IsVisible="True"
                                   VerticalOptions="CenterAndExpand"
                                   HorizontalOptions="CenterAndExpand"
                                   BackgroundColor="{StaticResource LightBGColor}"
                                   Color="{StaticResource PrimaryColor}"/>
            </Frame>
        </Grid>
    </ContentPage.Content>
</ContentPage>

Login.xaml.cs

using LoginExample.Data;
using LoginExample.Services;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Markup;
using Xamarin.Forms.Xaml;

namespace LoginExample
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class Login : ContentPage
    {
        public Login()
        {
            InitializeComponent();
        }

        protected override void OnAppearing()
        {
            btnLogin.IsEnabled = false;

            try
            {

                var perfilData = new PerfilData();

                var lst = perfilData.GetListAsync().Result;

                if (lst != null && lst.Any())
                {
                    //Got a Perfil/User Saved in the Sqlite/DB
                    var perfil = lst.First();

                    GlobalProperties.Perfil = perfil;

                    Application.Current.MainPage = new AppShell();
                }

            }
            catch (Exception)
            {
 
            }

            base.OnAppearing();
            btnLogin.IsEnabled = true;

            ActivIndicator.IsVisible = false;
        }

        private async void btnLogin_Clicked(object sender, EventArgs e)
        {
            //Check if the ActivIndicator is active/Show 
            if (ActivIndicator.IsVisible)
            {
                return;
            }

            //Make the ActivIndicator is active/Show
            ActivIndicator.IsVisible = true;

            string login = txtLoging.Text;
            string password = txtPassword.Text;

            try
            {
                var client = new LoginService();

                var loginPayload = await client.Login(login, password);

                GlobalProperties.Perfil = new Models.Perfil(loginPayload);

                var perfilData = new PerfilData();

                await perfilData.SaveAsync(GlobalProperties.Perfil);

                //Change Main Page => 
                Application.Current.MainPage = new AppShell();
            }
            catch (Exception ex)
            {
                await DisplayAlert("Erro", ex.Message, "OK");
            }
            finally
            {
                ActivIndicator.IsVisible = false;
            }

        }

    }
}