Dynamically show/hide Header or Footer of Xamarin.Forms.ListView

Question

Is there a way to dynamically show/hide the header of a ListView based on a condition at runtime.

Answer 1

You should use FooterTemplate and Footer properties. It works as ItemTemplate and ItemSource:

And bind to Footer property something nullable (object for example). Or you can use converter to convert: true -> new object() and false -> null

Also it is possible to create a subclass of ListView. My example (IsLoading property is what you searching for):

Xaml:

Code-behind:

public partial class LoadableListView : ListView
{
    public LoadableListView()
    {
        InitializeComponent();

        this.ItemAppearing += OnItemAppearing;
    }

    public static readonly BindableProperty IsLoadingProperty = BindableProperty.Create(
        nameof(IsLoading),
        typeof(bool),
        typeof(LoadableListView),
        false,
        propertyChanged: (bindable, oldValue, newValue) => 
        {
            var element = (LoadableListView)bindable;

            element.Footer = (bool)newValue ? new object() : null;
        }
    );
    public bool IsLoading
    {
        set => SetValue(IsLoadingProperty, value);
        get => (bool)GetValue(IsLoadingProperty);
    }

    public static readonly BindableProperty ScrolledDownCommandProperty = BindableProperty.Create(
        nameof(ScrolledDownCommand),
        typeof(ICommand),
        typeof(LoadableListView)
    );
    public ICommand ScrolledDownCommand
    {
        set => SetValue(ScrolledDownCommandProperty, value);
        get => (ICommand)GetValue(ScrolledDownCommandProperty);
    }

    void OnItemAppearing(object sender, ItemVisibilityEventArgs e)
    {
        if (ItemsSource == null) return;
        if (ScrolledDownCommand == null) return;

        object last = null;

        if (ItemsSource is IList)
        {
            var length = (ItemsSource as IList).Count;
            last = (ItemsSource as IList)[length - 1];
        }
        else 
        {
            foreach (var item in ItemsSource)
                last = item;
        }

        if (e.Item == last && ScrolledDownCommand.CanExecute(null))
            ScrolledDownCommand.Execute(null);

    }

Consuming: