Centering an Activityindicator on Xamarin.Forms
<p>I have the XAML above code and I am trying to put an ActivityIndicator on the center of the page after click the Button. I tried using examples of the web, but not succesful.</p>

<pre class="lang-cs prettyprint-override"><code>&lt;ScrollView&gt;
  &lt;StackLayout&gt;
    &lt;StackLayout Padding="30" Spacing="2" VerticalOptions="CenterAndExpand" HorizontalOptions="FillAndExpand"&gt;
      &lt;Label x:Name="lblUsuario" Text="ID do Usuário" TextColor="#555" FontSize="20" FontAttributes="Bold"/&gt;
      &lt;Entry x:Name="EntUsuario" Keyboard="Numeric" Placeholder="Digite usuário" PlaceholderColor="#CCC" FontSize="20" TextColor="#555" /&gt;
      &lt;Label x:Name="lblSenha" Text="Senha de acesso" TextColor="#555" FontSize="20" FontAttributes="Bold"/&gt;
      &lt;Entry x:Name="EntSenha" Placeholder="Digite sua senha" Keyboard="Default" IsPassword="True" FontSize="20" PlaceholderColor="#CCC" TextColor="#555" /&gt;   
    &lt;/StackLayout&gt;
    &lt;StackLayout Padding="30" VerticalOptions="CenterAndExpand" HorizontalOptions="FillAndExpand"&gt;  
      &lt;Button x:Name="BtnLogin" Text="Login" BorderColor="#CB9600" BackgroundColor="#F4B400" /&gt;
    &lt;/StackLayout&gt; 
  &lt;/StackLayout&gt;
&lt;/ScrollView&gt;
</code></pre>

<p>This is the beggining of the code:</p>

<pre><code>public partial class LoginPage : ContentPage
    {
        public LoginPage()
        {
            IsBusy = false;
            InitializeComponent();

            int contadorErroLogin = 0;
            string result = null;

            BtnLogin.Clicked += async (sender, e) =&gt;
                {
                    IsBusy = true;
</code></pre>

<p>When starts IsBusy = false but the screen seems like were true .</p>