Your task before coming to this session: know C# and .NET. Your mission during this session: learn how you can leverage your C# knowledge to build iOS apps. If you decide to accept this mission: be prepared to see how in just 60 minutes, a complete iOS app will appear in front of you. All using C#. This session will destroy itself after 60 minutes.

2. Building your first iOS app
using Xamarin
Gill Cleeren - @gillcleeren

3. Hi, I’m Gill!
Gill Cleeren
MVP and Regional Director
.NET Practice Manager @ Ordina
Trainer & speaker
@gillcleeren
gill@snowball.be

4. I’m a Pluralsight author!
• Courses on Windows 8, social and HTML5
• http://gicl.me/mypscourses

5. Agenda
• Overview of Xamarin and Xamarin.iOS
• Preparing for iOS development
• Xamarin.iOS fundamentals
• TableViews in iOS
• Adding navigation
• Optimizing the application
• Preparing for store deployment

6. Targets of this talk
• Understanding the fundamentals of iOS app development with
Xamarin
• See how a fully working app can be built

7. The demo scenario
• iOS Coffee Store Manager
• List of coffee
• Navigation to details page

8. DEMO
Looking at the finished application

9. Overview of Xamarin
and Xamarin.iOS

10. Hello Xamarin
• Xamarin enables developers to reach all major mobile platforms!
• Native User Interface
• Native Performance
• Shared Code Across Platforms
• C# & .NET Framework
• Toolset on top of Visual Studio
• Enables VS to create native iOS and Android apps
• Commercial product

11. Write Everything in C#
iOS, Android, Windows, Windows Phone, Mac
Billions of Devices covered!

12. The Xamarin platform
Xamarin
Xamarin.Android Xamarin.iOS Xamarin Forms

13. Xamarin.iOS
Anything you can do in Objective-C/Swift/XCode can be done in
C# and Visual Studio (or Xamarin Studio) with Xamarin!

14. iOS Runtime model
• Native ARMx code – no JIT is being used here
• Mono runtime provides system services such as Garbage Collection
• Full access to iOS frameworks such as MapKit as well as .NET BCL

15. A word on code-sharing
• Xamarin brings development time through the use of code-sharing
• Possible (currently!) using
• Shared projects:
• allows organizing the shared code
• #if directives for platform specific code
• PCL
• “include” the platforms we want to support
• Abstract to interfaces where platforms have specific implementations

16. Target architecture for a Xamarin app

17. Preparing for iOS development

18. What you need for Xamarin.iOS development
• Xamarin license (Xamarin.iOS)
• PC or Mac or Mac only
• Visual Studio or Xamarin Studio (Mac)
• XCode SDK (free)
• Optionally, a VM (VMWare or Parallels) with Windows 7 or 8
• Optionally, a device
• Optionally, a developer account

19. Installing Xamarin.iOS

20. iOS development on Windows
• Required: a Mac with latest OSX!
• There are no iOS simulators on Windows!
Windows
Visual Studio
Xamarin iOS plugin in
Visual Studio
Mac with OSX
Xamarin Build
Host
iOS SDK
XCode
Interface Builder
Device
iOS
Simulator

21. Connecting Windows & Mac

22. Developing on the Mac? Xamarin Studio!
• Optimized for cross-platform
mobile development
• Explore native APIs with code
completion
• World class Android and iOS
designers
• Powerful debugging on
simulator or device

23. DEMO
A quick look at the development setup
for Xamarin.iOS

24. Xamarin.iOS
fundamentals

25. File  New Project

26. File  New Project

27. Fundamental #1: Application structure
• Main.cs
• Entry point of the application
• Main app class is passed: AppDelegate
• AppDelegate.cs
• Main application class
• Builds the window
• Listens for OS events
• MainStoryboard.storyboard
• Visual design of the app and the flow between the screens

28. Application structure
• ****ViewController.cs
• Powers the view of the app
• View controller handles the interactions between
the user and the view
• ****ViewController.designer.cs
• Auto-generated file
• Glue between controls in the View and
representations in View controller
• Don’t edit this file yourself!

29. Application structure
• Info.plist
• Property list file
• Contains app properties such as app name, icons,
splash screen images…
• Entitlements.plist
• Allows specifying with capabilities the app is
receiving
• PassKit, iCloud…

30. Main.cs
• Entry point for the application
• Contains static Main
• Creates the app
• Passes name of application delegate

31. Application delegate

32. Fundamental #2: Views & Storyboards
• Views are most commonly created using a Storyboard
• Alternatives: code or *.xib files (XCode)
• Designer can be used to edit the Storyboard
• A Storyboard is a file that contains the visual designs of our application’s
screens as well as the transitions and relationships between the screens
• A screen inside a Storyboard is a Scene
• Each Scene represents a controller and the views it manages (content view hierarchy)
• Most templates create a new storyboard automatically
• An app can have more than one storyboard

33. Storyboard designer

34. Auto-generation of the *.designer.cs file
• Controller.cs contains our code
• Handles all that happens in the View
• Controller.designer.cs maps Storyboard controls
to C# objects
• Glue to make controls available in code
• Never edit this file manually!

35. The *.designer.cs file

36. Fundamental #3: Controllers
• iOS apps follow MVC pattern
• Actual code lives in View Controller classes
• Each ViewController inherits from UIViewController
• Different “base” view controllers exist
• NavigationViewController
• TabViewController
• SplitViewController
• …

37. Linking the view and the view controller
• When selecting a screen, we can select the black bar at the bottom
• Points to the View Controller
• Is an instance of UIViewController
• “Code behind”

38. Types of view controllers

39. Handling events in the view controller
• Controller needs to respond to user interaction
• Button press, navigation…
• We need to wire up code in the controller to listen for interaction
with a control
• To write code against controls, they are wired up in the *.designer.cs
• From then, we can work with them in the controller classes
• Controls are available for wiring up in the ViewDidLoad()

40. Responding to user interaction

41. DEMO
Creating our first iOS application together!

42. Adding a list
using
UITableView
I’d like an app for this
please.

43. The UITableView
• Lists of data can be visualized using the UITableView
• Can also be used for detail screens
• Contains cells (individual rows)
• Can have index and grouping (headers and footers)
• Can be placed in editing mode to allow data management
• Similar to Android: works with intermediate: UITableViewSource

44. Typical visualizations of the UITableView
Plain Index Grouped Edit

45. Participating classes
• UITableView
• UITableViewCell
• UITableViewSource
• UITableViewController

46. Loading data in the UITableView
• Each UITableView is assigned a UITableViewSource
• Table queries the source to learn how it should be rendered
• How many rows
• How high are the rows (if not default)
• Source supplies each cell view, populated with data
• 2 methods are required to show data
• RowsInSection
• returns an int count of the total number of rows of data the table should display
• GetCell
• return a UITableCellView populated with data for the corresponding row index passed to
the method

47. DEMO
Loading a list of data
I’d like an app for this
please.

48. Changing the appearance of the cells
• iOS comes with 4 built-in styles
• We can create our own styles as well

49. Built-in styles
Default Subtitle Value1 Value2

50. Using a built-in styles
cell = new UITableViewCell (UITableViewCellStyle.Default, cellIdentifier);
cell = new UITableViewCell (UITableViewCellStyle.Subtitle, cellIdentifier);
cell = new UITableViewCell (UITableViewCellStyle.Value1, cellIdentifier);
cell = new UITableViewCell (UITableViewCellStyle.Value2, cellIdentifier);

51. Creating your own cell layout
• It’s possible to provide an entirely different cell
• Different color
• Different control layout
• We need to create a new UITableViewCell
• Implements
• Constructor
• Creates the UI controls and sets the custom style properties
• UpdateCell
• Method for UITableView.GetCell to use to set the cell’s properties
• LayoutSubviews
• Set the location of the UI controls
• Possible to have more than one layout and create them based on content being displayed

52. DEMO
Changing our table view

53. Navigation

54. Navigation with the UINavigationController
• NavigationController is a lookless controller (UINavigationController)
• Is special type of UIViewController
• Allows navigating from one screen to another
• Doesn’t really manage a Content View Hierarchy
• Instead manages other View controllers
• + A specific, own view hierarchy including a navigation bar, title, back button…
• VERY common pattern in iOS

55. Navigation with the UINavigationController
• Allows us to navigate to second screen
• New views are pushed on the stack
Add to
stack

56. Navigation with the UINavigationController
• Can provide a back button on the title bar
• Pops the current controller off the back stack
• Loads previous one again
Remove from
stack

57. The NavigationController
• Automatically provides a title bar
• Can be used to display controller title

58. Concept of the root view controller
• Navigation controller is lookless
• Needs to be paired with a Root View Controller
• Root view controller is first controller in the stack
• Loads the first content view hierarchy into the window

59. Actual navigation: Segues
• Navigation/transition to another view is done (mostly) through
the use of Segues (pronounced Segways)
• Shown using arrow between views
• A storyboard can contain a segue with no source:
Sourceless segue
• This view will get loaded when the application starts

60. Actual navigation: Segues
• Adding segues can be done in the storyboard designer
• Gives choice of desired action

61. Passing data with segues
• PrepareForSegue is called before transition is executed
• We can access the next view controller using the DestinationViewController
property on the Segue

62. DEMO
Adding a second screen
and navigation

63. Optimizing the application

64. Application properties: info.plist

65. Application
image resources

66. Icon sizes
• Icons (and other images) are required to be added in different
resolutions
iOS 5/6 iOS 7/8 iOS 8 (6plus)
1x 2x 1x 2x 3x
App icon 57x57 114x114 Not supported 120x120 180x180
Spotlight 29x29 58x58 80x80 120x120
Settings 29x29 58x58 - - 87x87

67. entitlements.plist

68. DEMO
Adding application icons

69. Store
deployment

70. Deploying your apps to the store
• Store deployment involves 3 major parts
• Provisioning
• Creating a profile that includes code-signing information used to publish the app
• iTunes Connect information settings
• Online tool to add information that will be used for the application’s page in the App
Store
• Application Submission
• Signed binary can be uploaded to Apple for review
• Will be published in the store soon after that

71. Things to do before submitting
• App needs to meet Apple’s guidelines for quality and content
• Can be rejected
• Must be fixed and resubmitted
• Guidelines can be found at https://developer.apple.com/app-
store/review/guidelines/
• Test the app for crashes under normal circumstances
• Make sure the description matches what the app does!

72. Summary
• Xamarin.iOS leverages your C# knowledge to build apps for Android
• iOS is further from regular .NET development
• Getting your head around UI paradigms will take time!

73. Thanks!

74. Q&A

75. Building your first iOS app
using Xamarin
Gill Cleeren - @gillcleeren

76. Your feedback is important!
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