Tom Walker presented on building iOS applications with Xamarin and C#. He discussed how Xamarin allows building apps once that run on iOS and Android, with native performance. It uses C# and the .NET framework, while providing full coverage of platform APIs. He demonstrated the development environment, how Xamarin compiles to native code, and the iOS application lifecycle. Finally, he showed a demo of a Bing Images app built with Xamarin.

1. Building iOS
applications with
Xamarin and C#
• Microsoft and Xamarin MVP
• @Tinytoot | www.tomwalker.codes
• Tom Walker

2. Meet Tom Walker | @Tinytoot
• Founder @LdnOntNetDevs | LondonNetDevelopers.ca
• Windows Platform Development MVP
• Xamarin MVP
• Developer for 15+ years now focusing on mobile and web frontend
– Worked with large enterprises, startups and software companies
– Design & build internal enterprise and consumer facing software

3. Objectives
• Define the Problem
• How Xamarin Works
• Development Environment
• iOS Application Life Cycle
• Demo - Bing Images

4. Define the Problem

5. Silo Approach
Build Apps Multiple Times
• Multiple Teams
• Multiple Code Bases
• Different toolsets

6. Xamarin’s Unique Approach
• Native User Interface
• Native Performance
• Shared code across
platforms
• C# & .NET Framework
• Full API Coverage

7. How
Xamarin
Works

8. Xamarin.iOS does full Ahead Of
Time (AOT) compilation to produce
an ARM binary for Apple’s App
Store.
Native Performance
Xamarin.Android takes advantage
of Just In Time (JIT) compilation
on the Android device.

9. .NET + Windows APIs

10. .NET + iOS APIs | 100% Coverage

11. Always Up-to-Date
Track record of offering
same-day support:
iOS 5, iOS 6, iOS 7, iOS 7.1, iOS 8
Full support for:
• Google Glass
• Android Wear
• Amazon Fire TV
• More!

12. Distribute Everywhere
A Xamarin app can be distributed everywhere

13. Xamarin Studio
PC or Mac
Visual Studio Plugin
VS 2010 and Higher
Development Environment

14. Create native iOS, Android, Mac and
Windows apps in Visual Studio and C#

15. Visual Studio Integration
A single solution:
• iOS
• Android
• Windows Phone
• Windows Store
Leverage the entire
Microsoft ecosystem:
• ReSharper
• Team Foundation Server
• Your favorite code coverage
and profiling tools

17. Visual Studio Integration
Debug to:
• Emulators
• Devices
Integrated into toolbar
• Status
• Logs
• List of devices
Just Click Start Debugging!

18. Xamarin Designer for iOS
• World’s first iOS Designer
available in Xamarin Studio
and Visual Studio
• Follows familiar Visual Studio
designer idioms
• Supports all UIKit elements
• Edit custom and 3rd party
components
• Live preview of changes to
properties

19. iOS App Settings

20. Xamarin Component Store
Build Apps Faster
• Add high quality pre-built
app components directly
from Visual Studio and
Xamarin Studio
• Beautiful cross-platform UI
controls, cloud services and
enterprise backend
integrations are just a few
clicks away

21. iOS Application
Lifecycle & Structure

22. Background
Foreground
Not Running
Inactive
Active
Backgrounded
Suspended
Xamarin.iOS notifies us of all these states using various overrides
in AppDelegate.cs

23. MethodState
AppDelegate.cs
Not Running
Inactive
Active
Backgrounded
Suspended
OnActivated(UIApplication)
OnResignActivation
DidEnterBackground
WillEnterForeground
WillTerminate

24. AppDelegate.cs
AppDelegate
ViewController.cs
UIViewController
Storyboard

25. Model-View-Controller (MVC)
Model
View Controller
Performs Action
Changes ModelUpdates UI
User Sees Changes

26. Demo

27. Recap
• Define the Problem
• How Xamarin Works
• Development Environment
• iOS Application Life Cycle
• Demo - Bing Images

28. Thanks you
Questions?
• Microsoft and Xamarin MVP
• @Tinytoot | www.tomwalker.codes
• Tom Walker