Is there a way to bring up the native iOS and Android busy indicators with Xamarin Forms apps?

Question

I have a Forms app that takes a few seconds to populate data when I click on a viewCell.

Is there a way that I can show a circular busy indicator during this time through custom renderers or something like that?

Answer 1

You can implement the same by using ActivityIndicator control.

If you are expecting have busy-indicators on multiple pages, then would recommend to implement this using the ControlTemplate (it also allows you to define overlays if needed).

Page Template

<Application.Resources>
    <ResourceDictionary>
        <ControlTemplate x:Key="DefaultTemplate">
            <Grid> 
                         <!-- page content -->
                <ContentPresenter />
                         <!-- overlay -->
                <BoxView BackgroundColor="Black" Opacity="0.5" 
                        IsVisible="{TemplateBinding BindingContext.IsBusy}"/>
                        <!-- busy indicator with text --> 
                <Frame HorizontalOptions="Center" VerticalOptions="Center"
                     IsVisible="{TemplateBinding BindingContext.IsBusy}">
                    <StackLayout>
                        <ActivityIndicator IsRunning="{TemplateBinding BindingContext.IsBusy}" />
                        <Label Text="{TemplateBinding BindingContext.BusyText}" />
                    </StackLayout>
                </Frame>
            </Grid>
        </ControlTemplate>
    </ResourceDictionary>
</Application.Resources>

Sample usage:

XAML - assign template to page

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" 
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
            ControlTemplate="{StaticResource DefaultTemplate}"
            .. >
    .... 
</ContentPage>

View Model

public class BaseViewModel : ObservableObject
{
    bool _isBusy;
    public bool IsBusy
    {
        get => _isBusy;
        set => SetProperty(ref _isBusy, value);
    }

    string _busyText = "loading..";
    public string BusyText
    {
        get => _busyText;
        set => SetProperty(ref _busyText, value);
    }
}

public class TestViewModel : BaseViewModel
{
    public ICommand OnTapCommand {
        get => new Command(async (obj) =>
        {
            IsBusy = true;

            //do heavy lifting here
            await Task.Delay(2000);

            IsBusy = false;
        });
    }
...

Answer 2

You can use Acr.UserDialogs, it's a cross-platform package with busy indicators, dialogs, toasts, etc.

In your case, you need to use Loading.

using (Acr.UserDialogs.UserDialogs.Instance.Loading("your message here"))
{                
    //your long task here
}

For example...