Xamarin XAML ActivityIndicator, content doesn't show up - xaml

Question

I have a ListView in my XAML in which I show some data from my database, the problem is that in the meantime the ActivityIndicator show up as excpected, but when I set it to False, the content that is suppose to show up, doesn't. I don't know if I'm using the ActivityIndicator wrong, how I suppose to use it then?
XAML:
<?xml version="1.0" encoding="UTF-8"?>
<ContentPage...">
<ActivityIndicator x:Name="load1" Color="Red" IsRunning="true" />
<ContentPage.Content>
<ListView x:Name="XPS" ItemTapped="OnItemSelected"
...
</ListView>
</ContentPage.Content>
</ContentPage>
CS:
load1.IsRunning=false;

Answer 1

It looks like you're using ContentPage incorrectly. That page only supports having 1 child element (named Content). You're trying to define 2 different Content on 1 ContentPage. Xamarin.Forms just throws away your ListView so it will never show up.
So now you might wonder... How is that thing even useful? Good question! When you need to put multiple Views in 1 ContentPage you need to use a Layout. Xamarin.Forms has a bunch of layouts available that all behave differently - see https://developer.xamarin.com/guides/cross-platform/xamarin-forms/controls/layouts/ for some more details there.
Let's check out some code.... (I haven't actually tested this, I'm typing it directly into here, so you might need to fix some things...)
An updated ContentPage XAML:
<ActivityIndicator x:Name="load1" Color="Red" IsRunning="true" />
<ContentPage.Content>
<StackLayout x:Name="Layout">
<ActivityIndicator x:Name="load1" Color="Read" IsRunning="true"/>
<ListView x:Name="XPS" ItemTapped="OnItemSelected" Opacity="0"
...
</ListView>
</StackLayout>
</ContentPage.Content>
</ContentPage>
Now for some Code Behind...
public void LoadYourStuff()
{
LoadSomeTotallyAwesomeData();
WriteSomeTotallyAwesomeDataIntoAFancyListView();
PerhapsDoMoreFancyThings();
Layout.Children.Remove(load1);
XPS.Opacity = 1.0;
}

Answer 2

in your xmal file put :
<ActivityIndicator x:Name="popupView" VerticalOptions="Center" HorizontalOptions="Center" Color="DarkBlue" IsRunning="True" IsVisible="false" IsEnabled="True" />
when need this in C# code :
popupView.IsVisible = true;
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popupView.IsVisible = false;