In this webinar deck Craig Dunn shows what’s new in iOS 11 and how to take advantage of the latest updates – from drag-and-drop for iPad to machine learning and more – 100% in .NET and Visual Studio. Whether you’re building new or updating existing Xamarin.iOS apps, you’ll see how to implement new frameworks, APIs, and UI features, walk-through code samples, get expert tips and tricks, so you can start shipping iOS 11-ready apps to your users. Watch webinar at https://youtu.be/mXAbpXLT1vo

5. aka.ms/xamarin/ios11-todo11

7. 



8. // UINavigationController
NavigationBar.PrefersLargeTitles = true;
// UIViewController (second one in stack)
NavigationItem.LargeTitleDisplayMode = UINavigationItemLargeTitleDisplayMode.Never;
// AppDelegate
UINavigationBar.Appearance.LargeTitleTextAttributes = new UIStringAttributes
{
ForegroundColor = UIColor.FromRGB(0x5A, 0x86, 0x22), // 5A8622 dark-green
};

10. 

new

12. 
SafeAreaLayoutGuide

13. 
 MarginLayoutGuide

14. 



15. 




16. 
Safe Areavar safeGuide = View.SafeAreaLayoutGuide;
NSLayoutConstraint.ActivateConstraints(new NSLayoutConstraint[] {
CloseButton.TrailingAnchor.ConstraintEqualTo(safeGuide.TrailingAnchor, -23),
CloseButton.BottomAnchor.ConstraintEqualTo(safeGuide.BottomAnchor, -13),
CloseButton.WidthAnchor.ConstraintEqualTo(60),
CloseButton.HeightAnchor.ConstraintEqualTo(60)
});
-23
-13

17. 
var safeGuide = View.SafeAreaLayoutGuide;
NSLayoutConstraint.ActivateConstraints(new NSLayoutConstraint[] {
CloseButton.TrailingAnchor.ConstraintEqualTo(safeGuide.TrailingAnchor, -23),
CloseButton.BottomAnchor.ConstraintEqualTo(safeGuide.BottomAnchor, -13),
CloseButton.WidthAnchor.ConstraintEqualTo(60),
CloseButton.HeightAnchor.ConstraintEqualTo(60)
});

18. 
NSLayoutConstraint.ActivateConstraints(new NSLayoutConstraint[] {
CameraButton.TrailingAnchor.ConstraintEqualTo(CloseButton.LeadingAnchor, -23),
CameraButton.BottomAnchor.ConstraintEqualTo(safeGuide.BottomAnchor, -13),
CameraButton.WidthAnchor.ConstraintEqualTo(60),
CameraButton.HeightAnchor.ConstraintEqualTo(60)
});
Safe Area
-23
-13

19.  -13
var marginGuide = View.LayoutMarginsGuide;
NSLayoutConstraint.ActivateConstraints(new NSLayoutConstraint[] {
ClassificationLabel.LeadingAnchor.ConstraintEqualTo(marginGuide.LeadingAnchor),
ClassificationLabel.TrailingAnchor.ConstraintEqualTo(marginGuide.TrailingAnchor),
ClassificationLabel.BottomAnchor.ConstraintEqualTo(CloseButton.TopAnchor, -13),
ClassificationLabel.HeightAnchor.ConstraintEqualTo(120)
});
MarginMargin

20. 

21. 


22. 
var context = new LAContext();
// Face ID or Touch ID
context.CanEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, out var err1)
context.BiometryType == LABiometryType.TouchId ? "Touch ID" : "Face ID"
// PIN/Password
context.CanEvaluatePolicy(LAPolicy.DeviceOwnerAuthentication, out var err2)

23. 
var context = new LAContext();
// Face ID or Touch ID
context.CanEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, out var err1)
context.BiometryType == LABiometryType.TouchId ? "Touch ID" : "Face ID"
context.EvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason,
replyHandler);
// PIN/Password
context.CanEvaluatePolicy(LAPolicy.DeviceOwnerAuthentication, out var err2)
context.EvaluatePolicy(LAPolicy.DeviceOwnerAuthentication, localizedReason, replyHandler);

25. 


26. 
public UIDragItem[] GetItemsForBeginningDragSession(UITableView tableView,
IUIDragSession session, NSIndexPath indexPath)
{
var data = NSData.FromString(todoItems[indexPath.Row], NSStringEncoding.UTF8);
var itemProvider = new NSItemProvider();
itemProvider.RegisterDataRepresentation(UTType.PlainText,
NSItemProviderRepresentationVisibility.All,
(completion) =>
{
completion(data, null);
return null;
});
var dragItem = new UIDragItem(itemProvider);
return new UIDragItem[] { dragItem };
}

27. 
public bool CanHandleDropSession(UITableView tableView, IUIDropSession session)
{
return session.CanLoadObjects(typeof(NSString));
}
public UITableViewDropProposal DropSessionDidUpdate(UITableView tableView,
IUIDropSession session, NSIndexPath destinationIndexPath)
{
if (tableView.HasActiveDrag) {
// moving in current app
} else {
return new UITableViewDropProposal(UIDropOperation.Copy,
UITableViewDropIntent.InsertAtDestinationIndexPath);
}
}

28. public void PerformDrop(UITableView tableView, IUITableViewDropCoordinator coordinator)
{
// determine path from coordinator.DestinationIndexPath
coordinator.Session.LoadObjects<NSString>((items) =>
{
tableView.BeginUpdates();
foreach (var i in items)
{
// add items to table and data store
}
tableView.EndUpdates();
};
}

30. 


31. 
// MKMarkerAnnotationView
ClusteringIdentifier = "todo";
// ViewDidLoad
MapView.Register(typeof(TodoView),MKMapViewDefault.AnnotationViewReuseIdentifier);
MapView.Register(typeof(ClusterView),MKMapViewDefault.ClusterAnnotationViewReuseIdentifier);

32. 
// ClusterView : MKMarkerAnnotationView
var renderer = new UIGraphicsImageRenderer(new CGSize(40, 40));
var count = cluster.MemberAnnotations.Length;
var notDoneCount = CountByType(cluster.MemberAnnotations, MarkerType.NotDone);
Image = renderer.CreateImage((context) => {
// Fill full circle with tricycle color
TodoView.DoneColor.SetFill();
UIBezierPath.FromOval(new CGRect(0, 0, 40, 40)).Fill();
... Custom drawing

33. 
// MapView.GetViewForAnnotation
if (annotation is TodoAnnotation) {
//...
}
else if (annotation is MKClusterAnnotation) {
var cluster = annotation as MKClusterAnnotation;
var view = mapView.DequeueReusableAnnotation
(MKMapViewDefault.ClusterAnnotationViewReuseIdentifier) as ClusterView;
if (view == null) {
view = new ClusterView(cluster,
MKMapViewDefault.ClusterAnnotationViewReuseIdentifier);
}
return view;
}

35. 


customvision.ai

36. 
 developer.apple.com/machine-learning/



37. // Load
var assetPath = NSBundle.MainBundle.GetUrlForResource("VGG16.mlmodelc");
var model = MLModel.Create(assetPath, out err);
// Classify
var inputs = new NSDictionary<NSString, NSObject> (new NSString("image"), imageValue);
var inputFeatures = new MLDictionaryFeatureProvider (inputs, out error);
var outFeatures = model.GetPrediction (inputFeatures, out error2);
var predictionsDictionary = outFeatures.GetFeatureValue ("classLabelProbs").DictionaryValue;

39. 
Info.plist
developer.apple.com/support/app-store/

40. 

if (UIDevice.CurrentDevice.CheckSystemVersion(11, 0))
{
context.LocalizedReason = "Authorize for access to secrets";
}

41. 


if (picker.RespondsToSelector(
new Selector("setPredicateForEnablingPerson:")))
{
picker.PredicateForEnablingPerson = NSPredicate.FromFormat
("emailAddresses.@count > 0");
}

43. aka.ms/xamarin/ios11-todo11
aka.ms/xamarin/ios11
aka.ms/xamarin/ios11-samples
visualstudio.com/xamarin

44. Craig Dunn
Microsoft Docs