Session presented at vsug Belgium

1. Cross Platform Native Mobile App
Development for iOS, Android and
Windows Using the Power of C#
Marcel de Vries
Technology Manager
@marcelv

2. Agenda
Introduction to Xamarin& Mobile
Creating your first iOS app
Creating your first Android app
Code Sharing Tips
Summary

4. Building apps for the Mobile Space
Developer
User
Experience
productivity
Security &
privacy
Distribution:
Public or private
Corporate?
Which
platforms?
Application
Lifecycle
Management

5. Application types

6. Application types
Native look & feel
--
--
++
Camera Access
-++
+++
++
++
Secure service communication
JSON/REST
JSON/REST
JSON/SOAP
Access to calendar
--
--
++
Twitter integration
+-
+-
+
Distribution
++
AppStore presence
AppStore presence
GPS

7. 3 types
Xamarin
WP8/win8
Xaml + C#
Xamarin
Xamarin.iOS
Xamarin.Android
XCode
Objective-C
WP7
Silverlight
C#
Adobe AIR
ActionScript
Appcelerator Titanium
JavaScript > Native
Service2Media
Lua
Rhodes
Ruby + HTML
Android SDK
Java
Antenna
Rapid Scripting
Language
Kony
Javascript
Lua
Vendor tools
Sybase Unwired
“4GL” code gen
C#
App Logic
PhoneGap
HTML5 / CSS / JS
“Magic Box”
Shared
language
Hybrid

8. Xamarin History
Over a Decade of Enterprise Production Use
450,000
Reach 200,000
Developers
Developer
100+ Partners
Mark
100+ Components
2000
Ximian
Founded
2001
2003
2009
2011
Mono
Launches
Ximian
Acquired
by Novell
First iOS
product (now
Xamarin.iOS)
launches
2013
Xamarin
Founded
2012
First
Xamarin 2.0
release of
Xamarin.Mac Component
First
Store
Release of
Launch
Xamarin Test
Xamarin.Android Partner
Cloud
Program
Evolve 2013
Microsoft
Partnership

9. Anything you can do in Objective-C or Java can be
done in C# and Visual Studio with Xamarin.

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

11. Accelerate Development with Code
Sharing
Code sharing statistics from production Xamarin app: real-time
circuit simulator and editor used to design analog and digital
circuits

12. Completely Up-to-Date with Device OS releases
Always up-to-date with the
latest APIs from Apple and
Google.
Track record of offering sameday support: iOS 5, iOS 6, iOS
✔
6.1 and iOS 7.

14. UIKit
3rd party app
Tap app icon
main()
AppDelegate
UIApplicationMain()
FinishedLaunching
Event loop
HandleEvent
Quit foreground msg
OnActivated
OnResignActivation
Background
DidEnterBackground
WillTerminate
Restart tasks
Reload state
Refresh
Pause tasksUI
Throttle down
frame rates
Save state
Save data
Free resources

15. App model
View
UIView
Actions
Outlets
Controller
NavigationController
Model manipulation
Model
UIViewController

16. UITableView & Navigation

17. UITableView & Navigation
Data + table cells
UITableViewDataSource
UITableViewController
UITableViewSource
Events
UITableViewDelegate

18. Demo
iOS app basics

20. Android
Mobile OS made by google
Targets: Tablets and mobile phones

21. Mono for Android
Architectural picture of Mono for Android
.NET APIs
Android
Bindings
Mono (.NET Runtime)
MCW
ACW
Linux Kernel
Android.
*
Java.*
Dalvik (Java Runtime)

22. App model - Activity lifecycle
Activity
Launched
Restore
state here
Initialize
layout here
onCreate()
User navigates to
the activity
onStart()
onRestart()
onResume()
Another activity
App process comes into the
foreground
killed
Activity
running
The activity is no longer visible
Apps with higher state
The activitySave
is finishing or being onPause()
priority need
destroyed by the system
memory here
onStop()
onDestroy()
Activity shut
down
User returns to
the activity
User navigates to
the activity

23. Building apps on android
Intent
Intent
Activity
Intent
Content
Provider
View
Intent
Activity
Intent
View
Service
Intent
Broadcast
Receiver

24. Demo
Android app basics

25. Services
21%
Reusable
34%
Per App
Specific
16%
Windows
Phone
10%
Shared
84%
iOS
8%
Android
10%
Shared Logic
17%

26. Platform UI
Design Patterns for Reuse
Data
Serialization
Caching
Security
Application Business Logic
AuthN/AuthZ
Encryption
Data Self Destruction
Utilities
Platform Agnostic API
Device services
Analytics
Logging
Glue together the
application layers

27. Design Patterns for Reuse

28. Basics
View
Controller
Model
GPS
Motion sensors
Storage
Etc.
Services

29. Model Implementation
We implement the Model as a Singleton
Model Implements INotifyPropertyChanged
Easy to enlist subscribers
Facilitate automatic databinding in XAML
Model contains rich features such as filtering and
advanced selections
Easy to share logic

30. Model Implementation
public class MainModel : INotifyPropertyChanged
{
private static MainModel _model;
private static object _lockHandle = new object();
// Facilitates Windows Phone app resume
public void RestoreState(MainModel state)
{
_model = state;
}
public static MainModel Current
{
get {
if (_model == null) {
_model = new MainModel();
}
return _model;
}
}
public IEnumerable<Event> ActualEvents {
get {
// E.g. Complex linq stuff
}
}
}
// Model Usage:
var foo = MainModel.Current.ActualEvents;

31. Check your water level
XAML /
Device Specific
ValueConverter
Reusable Business Logic
Model Property
Value
Transformation

33. public class ISKEController
{
private static ISKEController _instance;
private ISKEDomainServicesoap _proxy;
public static ISKEController Current
{
get {
if (_instance == null) {
_instance = new ISKEController();
}
return _instance;
}
}
private void GetActualEvents (Action<object> OnSuccess, Action<Exception> OnFail)
{
// do some logic, or service call
// use actions to report result or trigger UI action
}
}

34. S
F
UIViewControlle
r
S
F
XAML View
Activity
public void OnSuccess(object
data)public void OnFailed(Exception
{
e)
//{Do something with data
Shared Controller
// Notify user
// Do GetActualEvents
something with error
}
}
(Action<object> OnSuccess,
Action<Exception> OnFail)
Web Services
S
F
Model
PropertyChanged(“Events”)
;

35. Demo
Action<T>

37. iOS
MonoTouch.CoreLocation
MonoTouch.CoreMotion
MonoTouch.AVFoundation
MonoTouch.AddressBook
MonoTouch.EventKit
…
Android:
Android.Hardware.Sensor
Android.Location
Android.Bluetooth
Android.Nfc
…
Windows Phone:
Microsoft.Devices.Sensors.Gyroscope
Microsoft.Devices.Sensors.Accelerometer
Microsoft.Devices.Sensors.Compass
Microsoft.Devices.Sensors.Motion
…

38. Partial classes &
methods

39. A.cs
partial class A
{
// Half of the implementation
}
A.extra.cs
partial class A
{
// The other half
}

40. A.cs
A.iOS.cs
partial classAlways private and returns
A
{
void
// Declare the method here
partial void DoSomethingEx();
partial class A
{
// Provide the implementation here
partial void DoSomethingEx()
{
public void DoSomething()
// Do something iOS specific
{
}
// Some shared logic be used from shared
}
Can
Leaves room for specific
DoSomethingEx();
logic
implementation
}
}

42. Demo

43. Summary
Xamarin provides Native Cross platform
capabilities
– Best of all worlds
Use the power of C#
– BCL, LINQ, ASYNC, etc
Keep abstractions as simple as possible
– Avoid IOC, Big frameworks
– Remember your on a mobile device, each cycle
counts!