iOS UIRefreshControl

Edit

Available from iOS 6, MvvmCross 5.0.0.

MvvmCross has a extended version of UIRefreshControl on iOS which exposes RefreshCommand, IsRefreshing, and Message. This control is useful when you have a scrollable View such as a UITableView, UICollectionView or a UIScrollView, you want to refresh, when scrolling it to the top and pulling it down. It is also known as pull to refresh.

RefreshCommand

MvxUIRefreshControl internally listens to the ValueChanged event on the UIRefreshControl, to fire the RefreshCommand command when the event is triggered. This allows you to bind an Command from your ViewModel to this event to refresh or load more data.

IsRefreshing

This property is used to toggle the visual representation of the UIRefreshControl. If set to true the UIRefreshControl will show a loading indicator along with the set message. If set to false no loading indicator will be shown. This should always be set from the UI Thread.

Message

This property is the message to be shown when IsRefreshing is true.

Sample usage

ViewModel

private bool _isLoading;
public bool IsLoading
{
    get => _isLoading;
    set => SetProperty(ref _isLoading, value);
}

private string _loadingMessage;
public string LoadingMessage
{
    get => _loadingMessage;
    set => SetProperty(ref _loadingMessage, value);
}

private MvxCommand _refreshCommand;
public ICommand RefreshCommand => _refreshCommand = _refreshCommand ?? new MvxCommand(DoRefreshCommand);

private void DoRefreshCommand()
{
    IsLoading = true;
    LoadingMessage = "Loading dogs and kittens...";

    // load stuff

    IsLoading = false;
}

View

var refreshControl = new MvxUIRefreshControl();

// RefreshControl is a property on a `UIViewController`
RefreshControl = refreshControl;

var set = this.CreateBindingSet<MyView, MyViewModel>();
set.Bind(refreshControl).For(r => r.IsRefreshing).To(vm => vm.IsLoading);
set.Bind(refreshControl).For(r => r.RefreshCommand).To(vm => vm.RefreshCommand);
set.Bind(refreshControl).For(r => r.Message).To(vm => vm.LoadingMessage);
set.Apply();

Resources

• https://montemagno.com/mvxuirefreshcontrol-for-mvvmcross/