Cross Platform Native Mobile App Development for iOS, Android and

Windows Using the Power of C#

Marcel de VriesTechnology Manager @marcelv

AgendaIntroduction to Xamarin& MobileCreating your first iOS appCreating your first Android appCode Sharing TipsSummary

Building mobile apps

Building apps for the Mobile SpaceUser Experience Developer

productivity

Which platforms?

Application Lifecycle

Management

Distribution: Public or private

Corporate?Security &

privacy

Application types

Application types

Native look & feel -- -- ++Camera Access -- +- ++GPS ++ ++ ++

Secure service communication JSON/REST JSON/REST JSON/SOAP

Access to calendar -- -- ++Twitter integration +- +- +Distribution ++ AppStore presence AppStore presence

3 types

App Logic

Vendor tools “Magic Box” Hybrid

XCodeObjective-C

WP7 Silverlight

C#

Android SDKJava

Appcelerator TitaniumJavaScript > Native

PhoneGapHTML5 / CSS / JS

Adobe AIRActionScript

AntennaRapid Scripting

Language

Service2MediaLua C#

XamarinXamarin.iOS

WP8/win8 Xaml + C#

XamarinXamarin.Android

RhodesRuby + HTML

Sybase Unwired“4GL” code gen

Shared languageKony

Javascript Lua

Xamarin HistoryOver a Decade of Enterprise Production Use

2000

Ximian Founded

2001

MonoLaunches

2003

Ximian Acquired by Novell

2009

First iOS product (now Xamarin.iOS) launches

2011

Xamarin Founded

First Release of Xamarin.Android

2012

First release of Xamarin.Mac

LaunchPartnerProgram

2013

Xamarin 2.0

Component Store

Xamarin TestCloud

Evolve 2013

Microsoft Partnership

Reach 200,000Developer

Mark

450,000 Developers

100+ Partners100+ Components

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

Xamarin.iOS does full Ahead Of Time (AOT) compilation to produce an ARM binary suitable for Apple’s App Store.

Native Performance

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 same-day support: iOS 5, iOS 6, iOS 6.1 and

iOS 7.

✔

iOS

3rd party app

AppDelegate

UIKit

Tap app icon

main()

UIApplicationMain()

Quit foreground msg

Background

Event loop

FinishedLaunching

HandleEvent

OnResignActivation

DidEnterBackgroundWillTerminate

Save stateSave data

Free resources

Pause tasksThrottle down

frame rates

OnActivatedRestart tasksReload stateRefresh UI

App model

View

Controller

Model

NavigationController

Model manipulation

UIView

UIViewController

Outlets Actions

UITableView & Navigation

UITableView & Navigation

UITableViewController

UITableViewDataSource

UITableViewDelegate

UITableViewSource

Data + table cells

Events

DemoiOS app basics

Android

Android

Mobile OS made by googleTargets: Tablets and mobile phones

Mono for AndroidArchitectural picture of Mono for Android

Linux Kernel

Mono (.NET Runtime) Dalvik (Java Runtime)

.NET APIs Android Bindings

Android.* Java.*MCW

ACW

App model - Activity lifecycleActivity

Launched

onCreate()

onStart()

onResume()

onPause()

onStop()

onDestroy()

onRestart()

Activity shut down

Activity running

User navigates to the activity

Apps with higher priority need

memory

User returns to the activity

User navigates to the activity

Another activity comes into the foreground

App process killed

The activity is no longer visible

The activity is finishing or being destroyed by the system

Initialize layout here

Save state here

Restore state here

Building apps on android

Activity Activity

View View

Intent

IntentBroadcast Receiver

Service

Content Provider

Intent

Intent

Intent

Intent

Inte

nt

DemoAndroid app basics

The promise…

Reusable34%

Shared Logic17%

Android10%

iOS8%

Win-dows Phone10%

Services21%

Shared84%

Specific16%

Per App

DataSerialization

Caching

SecurityAuthN/AuthZEncryption

Data Self Destruction

UtilitiesAnalyticsLogging

Device services

Platform Agnostic API

Application Business Logic

Platform UI

Design Patterns for Reuse

Glue together the application layers

Design Patterns for Reuse

Basics

Services

ModelController

Etc.

GPS

Storage

Motion sensors

View

Model ImplementationWe implement the Model as a SingletonModel Implements INotifyPropertyChangedEasy to enlist subscribers

Facilitate automatic databinding in XAMLModel contains rich features such as filtering and advanced selections

Easy to share logic

Model Implementationpublic 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

Reusable Business Logic

Device SpecificXAML /

ValueConverter

Model PropertyValue

Transformation

Controller implementation

Controller is a singleton as well• Maintains a reference to the service proxy• Singleton helps to prevent threading issues with proxy initialization

on iOS device

Expose public methods to provide business logic

Handle service calls and threading in the controller as much as possible

• Now much easier with async/await

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 }}

Controller implementation

Callback pattern

Shared Controller

UIViewController

XAML View Activity

Web Services

S F S F S F

ModelGetActualEvents

(Action<object> OnSuccess, Action<Exception> OnFail)

PropertyChanged(“Events”);

public void OnFailed(Exception e){ // Do something with error}

public void OnSuccess(object data){ // Do something with data // Notify user}

DemoAction<T>

What about accessing device capabilities?

Platform agnostic API for capabilities• If you squint, device capabilities look the same

across platformsiOS

MonoTouch.CoreLocationMonoTouch.CoreMotionMonoTouch.AVFoundationMonoTouch.AddressBookMonoTouch.EventKit…

Android: Android.Hardware.SensorAndroid.LocationAndroid.BluetoothAndroid.Nfc…

Windows Phone: Microsoft.Devices.Sensors.GyroscopeMicrosoft.Devices.Sensors.AccelerometerMicrosoft.Devices.Sensors.CompassMicrosoft.Devices.Sensors.Motion…

Use device abstractions!Xamarin.Mobile or Roll Your

Own

Partial classes & methods

Partial classes 101

• Span a class implementation over multiple files

• Useful for partly generated code• ...or separating shared implementation and

device specific implementation

partial class A{    // Half of the implementation}

partial class A{    // The other half}

A.cs

A.extra.cs

Partial methods 101

• Put implementation details in a partial method and put shared logic around it

partial class A{ // Declare the method here partial void DoSomethingEx(); public void DoSomething() { // Some shared logic DoSomethingEx(); }}

partial class A{    // Provide the implementation here partial void DoSomethingEx() { // Do something iOS specific }}

Can be used from shared logic

Leaves room for specific

implementation

Always private and returns void

A.cs

A.iOS.cs

Device Abstraction Patterns

DemoDevice Abstractions

SummaryXamarin 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!