private void RemoveTracker(OverlayTrackerTileProvider tracker)
{
TileOverlay overlay = tracker.TileOverlay;
tracker.RemoveAllTiles();
overlay.Remove();
_TileTrackers.Remove(tracker);
}
private void AddTrackerForOverlay(SKMapOverlay sharedOverlay)
{
OverlayTrackerTileProvider tracker = new OverlayTrackerTileProvider(Context, NativeMap, sharedOverlay);
TileOverlayOptions overlayOptions = new TileOverlayOptions().InvokeTileProvider(tracker);
TileOverlay overlay = NativeMap.AddTileOverlay(overlayOptions);
tracker.TileOverlay = overlay;
_TileTrackers.Add(tracker);
}
private void MapOverlaysCollectionChanged(object sender, NotifyCollectionChangedEventArgs args)
{
IEnumerable <SKMapOverlay> newItems = args.NewItems?
.OfType <SKMapOverlay>()
.DefaultIfEmpty();
IEnumerable <SKMapOverlay> removedItems = args.OldItems?
.OfType <SKMapOverlay>()
.DefaultIfEmpty();
switch (args.Action)
{
case NotifyCollectionChangedAction.Add:
{
foreach (SKMapOverlay mapOverlay in newItems)
{
AddTrackerForOverlay(mapOverlay);
}
break;
}
case NotifyCollectionChangedAction.Remove:
{
foreach (SKMapOverlay mapOverlay in removedItems)
{
OverlayTrackerTileProvider tracker = FindTrackerForOverlay(mapOverlay);
if (tracker != null)
{
RemoveTracker(tracker);
}
}
break;
}
case NotifyCollectionChangedAction.Replace:
{
foreach (SKMapOverlay mapOverlay in removedItems)
{
OverlayTrackerTileProvider tracker = FindTrackerForOverlay(mapOverlay);
if (tracker != null)
{
RemoveTracker(tracker);
}
}
foreach (SKMapOverlay mapOverlay in newItems)
{
AddTrackerForOverlay(mapOverlay);
}
break;
}
case NotifyCollectionChangedAction.Reset:
{
List <OverlayTrackerTileProvider> oldTrackers = new List <OverlayTrackerTileProvider>(_TileTrackers);
foreach (OverlayTrackerTileProvider tracker in oldTrackers)
{
RemoveTracker(tracker);
}
foreach (SKMapOverlay overlay in _SharedControl.MapOverlays)
{
AddTrackerForOverlay(overlay);
}
break;
}
}
}