How to run the code with another thread behind the scene

Question

I'm working on xamarin. The tabbed page on load when is clicked. And i want to load the data by api behind the scene and showing the loading indicator.

protected override void OnAppearing()
{
    base.OnAppearing();

    if (!_appeared)
    {
        // Want this to be run behind
        ProductViewData productViewData = new ProductViewData();
        products = productViewData.GetProductList("10");
        count = 10;

        productListView.ItemsSource = products;

        _appeared = true;
    }
}

Thanks for any helping.

Answer 1

You can make the method async and await your response. You shouldn't update UI thread from another thread, so using Task.Run is a bad idea. Take a look at Async Programming if you need more details

protected override async void OnAppearing()
{
    base.OnAppearing();

    if (!_appeared)
    {
        try
        {
            ProductViewData productViewData = new ProductViewData();
            // make the method asynchronous
            products = productViewData.GetProductListAsync("10");
            count = 10;

            productListView.ItemsSource = products;

            _appeared = true;
        }
        catch(Exception exception)
        {
            // good idea to catch any network exceptions
        }
    }
}

Answer 2

Just put inside the Task.Run and it will work

protected override void OnAppearing()
    {
        base.OnAppearing();

        if (!_appeared) // Avoid repeat loding
        {
            activity.IsEnabled = true;
            activity.IsRunning = true;
            activity.IsVisible = true;

            var task = Task.Run(() =>
            {
                ProductViewData productViewData = new ProductViewData();
                products = productViewData.GetProductList("10");
                count = 10;
                productListView.ItemsSource = products;
            });

            _appeared = true;
        }
    }