public Task <string> FromGallery()
{
UIWindow window = GetRootWindow();
if (window == null)
{
throw new InvalidOperationException("No root controller.");
}
var viewController = window.RootViewController;
while (viewController.PresentedViewController != null)
{
viewController = viewController.PresentedViewController;
}
var ndelegate = new GalleryDelegate(viewController);
var od = Interlocked.CompareExchange(ref pickerDelegate, ndelegate, null);
if (od != null)
{
throw new InvalidOperationException("Delegate still running");
}
var picker = new GalleryController(ndelegate)
{
MediaTypes = new string[] { "public.image" },
SourceType = UIImagePickerControllerSourceType.PhotoLibrary
};
viewController.PresentViewController(picker, true, null);
return(ndelegate.Task.ContinueWith(
t =>
{
Interlocked.Exchange(ref pickerDelegate, null);
return t;
}).Unwrap());
}
internal GalleryController(GalleryDelegate mpDelegate)
{
base.Delegate = mpDelegate;
}