Get the Most Out of iOS 11 with Visual Studio Tools for Xamarin
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The document contains code snippets related to the implementation of a Xamarin.iOS application, focusing on user interface elements like navigation controllers, constraints for safe areas, and drag-and-drop functionality in a table view. It also covers biometric authentication with Face ID and Touch ID, as well as map view configuration and custom rendering for clustered annotations. Lastly, it touches on machine learning model loading and prediction using Apple's Core ML framework.
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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](https://image.slidesharecdn.com/ios11-webinar-pdf-171214153813/85/Get-the-Most-Out-of-iOS-11-with-Visual-Studio-Tools-for-Xamarin-16-320.jpg)
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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)
});](https://image.slidesharecdn.com/ios11-webinar-pdf-171214153813/85/Get-the-Most-Out-of-iOS-11-with-Visual-Studio-Tools-for-Xamarin-17-320.jpg)
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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](https://image.slidesharecdn.com/ios11-webinar-pdf-171214153813/85/Get-the-Most-Out-of-iOS-11-with-Visual-Studio-Tools-for-Xamarin-18-320.jpg)
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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](https://image.slidesharecdn.com/ios11-webinar-pdf-171214153813/85/Get-the-Most-Out-of-iOS-11-with-Visual-Studio-Tools-for-Xamarin-19-320.jpg)
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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 };
}](https://image.slidesharecdn.com/ios11-webinar-pdf-171214153813/85/Get-the-Most-Out-of-iOS-11-with-Visual-Studio-Tools-for-Xamarin-26-320.jpg)
Get the Most Out of iOS 11 with Visual Studio Tools for Xamarin
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- 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
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- 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
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- 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);
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- 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(); }; }
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- 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; }
- 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;
- 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"); }