UICollectionViewCell DequeueIceCreamCell(IceCream iceCream, NSIndexPath indexPath)
{
var cell = CollectionView.DequeueReusableCell(IceCreamCell.ReuseIdentifier, indexPath) as IceCreamCell;
if (cell == null)
{
throw new Exception("Unable to dequeue am IceCreamCell");
}
cell.RepresentedIceCream = iceCream;
// Use a placeholder sticker while we fetch the real one from the cache.
var cache = IceCreamStickerCache.Cache;
cell.StickerView.Sticker = cache.PlaceholderSticker;
// Fetch the sticker for the ice cream from the cache.
cache.GetSticker(iceCream, (sticker) => {
// If the cell is still showing the same ice cream, update its sticker view.
if (cell.RepresentedIceCream == iceCream)
{
cell.StickerView.Sticker = sticker;
}
});
return(cell);
}
public UIViewController InstantiateCompletedIceCreamController(IceCream iceCream)
{
// Instantiate a `BuildIceCreamViewController` and present it.
var controller = Storyboard.InstantiateViewController(CompletedIceCreamViewController.StoryboardIdentifier) as CompletedIceCreamViewController;
if (controller == null)
{
throw new Exception("Unable to instantiate an CompletedIceCreamViewController from the storyboard");
}
controller.IceCream = iceCream;
return(controller);
}
MSMessage ComposeMessage(IceCream iceCream, string caption, MSSession session = null)
{
var components = new NSUrlComponents {
QueryItems = iceCream.QueryItems
};
var layout = new MSMessageTemplateLayout {
Image = iceCream.RenderSticker(true),
Caption = caption
};
var message = new MSMessage(session ?? new MSSession())
{
Url = components.Url,
Layout = layout
};
return(message);
}
public void GetSticker(IceCream iceCream, Action <MSSticker> completion)
{
if (iceCream.Base == null || iceCream.Scoops == null || iceCream.Topping == null)
{
throw new Exception("Stickers can only be created for completed ice creams");
}
// Determine the URL for the sticker.
var fileName = $"{iceCream.Base.RawValue}{iceCream.Scoops.RawValue}{iceCream.Topping.RawValue}.png";
var url = Path.Combine(cacheURL, fileName);
// Check if the sticker already exists at the URL
if (!NSFileManager.DefaultManager.FileExists(url))
{
// Create the sticker image and write it to disk.
var image = iceCream.RenderSticker(false);
var imageData = image?.AsPNG();
if (image == null || imageData == null)
{
throw new Exception("Unable to build image for ice cream");
}
try {
File.WriteAllBytes(url, imageData.ToArray());
} catch {
throw new Exception("Failed to write sticker image to cach");
}
}
NSError error;
var sticker = new MSSticker(new NSUrl($"file://{url}"), "Ice Cream", out error);
if (error != null)
{
throw new Exception($"Failed to write image to cache, error: {error.LocalizedDescription}");
}
completion?.Invoke(sticker);
}