Xamarin form activityindicator not working in constructor - xamarin

Question

I am working on Xamarin forms,I need to display data from database on form load.
So I want to display Activity indicator when database operation is taking time.
I am setting ActivityIndicator to true on constructor load andat the end setting it to false.
But its not showing
Here is code
Xaml is as below
<ContentPage.Content>
<StackLayout VerticalOptions="StartAndExpand" Padding="5,5,5,5">
<ListView HasUnevenRows="True" RowHeight="100" HeightRequest="-1" x:Name="ListViewAppointments" VerticalOptions="StartAndExpand">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid Padding="20,0,20,0" ColumnSpacing="20">
<Grid.RowDefinitions>
<RowDefinition Height="40"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="40"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="40"></ColumnDefinition>
</Grid.ColumnDefinitions>
<!--<BoxView Color="#f7f7f7" Grid.Column="0" Grid.RowSpan="2"/>
<BoxView Color="#ffffff" Grid.Column="1" Grid.RowSpan="2"/>-->
<Image Grid.RowSpan="2" Grid.Column="0" Source="documenticon.png" Aspect="AspectFit"></Image>
<Label TextColor="#00344e" FontAttributes="Bold" Text="{Binding ReportName}" Grid.Row="0" Grid.Column="1" VerticalTextAlignment="End"></Label>
<Label TextColor="#0073ae" Text="{Binding PrintDate}" Grid.Row="1" Grid.Column="1" VerticalTextAlignment="Start"></Label>
<Image Grid.RowSpan="2" Grid.Column="2" Source="downloadicon.png" Aspect="AspectFit"></Image>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<ActivityIndicator x:Name="ActLoder" HorizontalOptions="CenterAndExpand" Color="#ffffff" VerticalOptions="CenterAndExpand" />
</StackLayout>
</ContentPage.Content>
and code behind
public partial class CurrentDocuments : ContentPage
{
public CurrentDocuments()
{
InitializeComponent();
new Task(Initializer).Start();
}
public async void Initializer()
{
ShowLoader(true);
NavigationPage.SetBackButtonTitle(this, "");
Title = "CURRENT DOCUMENTS";
DocumentsResponse appointsData = null;
await Task.Run(async () =>
{
appointsData = await GetCurrentDocuments();
}).ContinueWith(_ =>
{
Device.BeginInvokeOnMainThread(() => {
ListViewAppointments.ItemsSource = appointsData.ListOfDocuments;
ShowLoader(false);
});
});
}
private async Task<DocumentsResponse> GetCurrentDocuments()
{
DocumentManager manager = new DocumentManager();
var result = await manager.GetCurrentDocuments(Application.Current.Properties["SessionId"].ToString());
return result;
}
public async void ShowLoader(bool isVisible)
{
ActLoder.IsRunning = isVisible;
ActLoder.IsVisible = isVisible;
ActLoder.IsEnabled = true;
}
}

Answer 1

GetCurrentDocuments is returning a Task<DocumentsResponse> and you are not awaiting it to activate that Task.
var appointsData = await GetCurrentDocuments();
But, you should not await in an .ctor.
Something like this will get you started (I did this on the fly, so correct any typos/syntax errors/etc:
public partial class CurrentDocuments : ContentPage
{
public CurrentDocuments()
{
InitializeComponent();
new Task(Initializer).Start();
}
public async void Initializer()
{
ShowLoader(true);
NavigationPage.SetBackButtonTitle(this, "");
Title = "CURRENT DOCUMENTS";
Task<DocumentsResponse> appointsData;
await Task.Run(async () =>
{
appointsData = await GetCurrentDocuments();
}).ContinueWith(_ =>
{
Device.BeginInvokeOnMainThread(() => {
ListViewAppointments.ItemsSource = appointsData;
ShowLoader(false);
});
});
}
public void ShowLoader(bool isVisible)
{
ActLoder.IsRunning = isVisible;
ActLoder.IsVisible = isVisible;
ActLoder.IsEnabled = true;
}
public async Task<DocumentsResponse> GetCurrentDocuments()
{
DocumentManager manager = new DocumentManager();
var result = await manager.GetCurrentDocuments(Application.Current.Properties["SessionId"].ToString());
return result;
}
}