private static void OnCurrentPlaceholderStateChanged(DependencyObject d, DependencyPropertyChangedEventArgs args)
{
if (args != null && (args.NewValue != args.OldValue))
{
PlaceholderState state = (PlaceholderState)args.NewValue;
//initialise
if (layoutManager == null)
{
layoutManager = (new PlaceholderStateManager(d as Grid)
{
PlaceholderItems = GetPlaceholderStateItems(d) as IList <PlaceholderStateItem>
});
}
if (layoutManager != null)
{
// set the layout to loading Template.
if (state == PlaceholderState.Loading)
{
layoutManager.SwitchToPlaceholderTemplate(d as Grid, state);
}
else if (state == PlaceholderState.NoState)
{
layoutManager.SwitchToAppContent(d as Grid);
}
}
}
}
public async void LoadDifferentStates()
{
CurrentState = PlaceholderState.Loading;
await Task.Delay(TimeSpan.FromSeconds(5));
CurrentState = PlaceholderState.NoState;
}
protected void UpdateScores()
{
// don't display any scores or placeholder until the first Scores_Set has been called.
// this avoids scope changes flickering a "no scores" placeholder before initialisation of song select is finished.
if (!scoresLoadedOnce)
{
return;
}
getScoresRequest?.Cancel();
getScoresRequest = null;
pendingUpdateScores?.Cancel();
pendingUpdateScores = Schedule(() =>
{
if (api?.IsLoggedIn != true)
{
PlaceholderState = PlaceholderState.NotLoggedIn;
return;
}
PlaceholderState = PlaceholderState.Retrieving;
loading.Show();
getScoresRequest = FetchScores(scores => Schedule(() =>
{
Scores = scores;
PlaceholderState = Scores.Any() ? PlaceholderState.Successful : PlaceholderState.NoScores;
}));
if (getScoresRequest == null)
{
return;
}
getScoresRequest.Failure += e => Schedule(() =>
{
if (e is OperationCanceledException)
{
return;
}
PlaceholderState = PlaceholderState.NetworkFailure;
});
api.Queue(getScoresRequest);
});
}
internal void SwitchToPlaceholderTemplate(Grid layout, PlaceholderState placeholderState)
{
// save original content if not already done
if (_previousState == PlaceholderState.NoState)
{
_savedContent = layout.Children.ToList();
}
_previousState = placeholderState;
//get PlaceholderStateItem
var template = GetPlaceholderTemplate(placeholderState);
int repeat = template.RepeatItem;
DataTemplate itemTemplate = template.PlaceholderTemplate;
//clear UI
layout.Children.Clear();
//if reapet = 1 or we can find an item template then only repeat this once
if (repeat == 1 || itemTemplate == null)
{
layout.Children.Add(template);
}
else
{
var repeatItemsSource = new List <int>();
for (int i = 0; i < repeat; i++)
{
repeatItemsSource.Add(repeat);
}
var ls = new ListView();
ls.SelectionMode = ListViewSelectionMode.None;
ls.ShowsScrollingPlaceholders = false;
//ls.CanBeScrollAnchor = false;
//insert template
ls.ItemTemplate = itemTemplate;
ls.ItemsSource = repeatItemsSource;
layout.Children.Add(ls);
}
}
internal void SwitchToAppContent(Grid g)
{
_previousState = PlaceholderState.NoState;
//clear placeholder state
g.Children.Clear();
// Put the original content back in.
foreach (var item in _savedContent)
{
try
{
g.Children.Add(item);
}
catch (System.Exception)
{
}
}
}
public void SetRetrievalState(PlaceholderState state)
{
PlaceholderState = state;
}
private PlaceholderStateItem GetPlaceholderTemplate(PlaceholderState placeholderState)
{
var template = PlaceholderItems.Where(a => a.StateItemKey == placeholderState).FirstOrDefault();
return(template);
}
public static void SetCurrentPlaceholderState(UIElement element, PlaceholderState value)
{
element.SetValue(CurrentPlaceholderStateProperty, value);
}
