Cross Platform Native Mobile App
Development for iOS, Android and
Windows Using the Power of C#

Marcel de Vries
Technology Manager
@marcelv
Agenda
Introduction to Xamarin& Mobile
Creating your first iOS app
Creating your first Android app
Code Sharing Tips
Summary
Building apps for the Mobile Space
Developer

User
Experience

productivity

Security &
privacy

Distribution:
Public or private
Corporate?

Which
platforms?
Application
Lifecycle
Management
Application types
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
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
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
Anything you can do in Objective-C or Java can be
done in C# and Visual Studio with Xamarin.
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.
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
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.
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
App model
View

UIView
Actions

Outlets
Controller
NavigationController

Model manipulation

Model

UIViewController
UITableView & Navigation
UITableView & Navigation
Data + table cells

UITableViewDataSource

UITableViewController

UITableViewSource

Events

UITableViewDelegate
Demo
iOS app basics
Android

Mobile OS made by google
Targets: Tablets and mobile phones
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)
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
Building apps on android

Intent

Intent

Activity
Intent

Content
Provider

View

Intent

Activity

Intent

View

Service

Intent

Broadcast
Receiver
Demo
Android app basics
Services
21%

Reusable
34%

Per App
Specific
16%

Windows
Phone
10%
Shared
84%

iOS
8%
Android
10%

Shared Logic
17%
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
Design Patterns for Reuse
Basics
View

Controller
Model

GPS
Motion sensors
Storage
Etc.

Services
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
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;
Check your water level
XAML /

Device Specific

ValueConverter

Reusable Business Logic
Model Property
Value
Transformation
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
}
}
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”)
;
Demo
Action<T>
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
…
Partial classes &
methods
A.cs
partial class A
{
// Half of the implementation
}

A.extra.cs
partial class A
{
// The other half
}
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
}

}
Demo
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!

Cross platform native mobile app development for iOS, Android and Windows using the power of C#

Editor's Notes

  • #7 Rhodes – rhomobile ; Ruby + HTML; MVC architectuur met extra framework zakenvoor sync en ORMAntenna: Appcellerator: pure javascriptoplossing met cross platform API. Wel: native UI bindings. Interpreted door meegedeployde interpreter
  • #27 Data Self Destruction: when a device gets compromised, you’d want some way built into the app to enable data self destruction. This might be some generic security class that is able to wipe the data portion of the application based on some (remote) signal.
  • #28 Controller acts as a Mediator in Cocoa interpretation of MVC
  • #32 Photo Credit: &lt;a href=&quot;http://www.flickr.com/photos/45409431@N00/3499224439/&quot;&gt;marfis75&lt;/a&gt; via &lt;a href=&quot;http://compfight.com&quot;&gt;Compfight&lt;/a&gt; &lt;a href=&quot;http://creativecommons.org/licenses/by-sa/2.0/&quot;&gt;cc&lt;/a&gt;