This document summarizes Chris Hardy's presentation on mobile development platforms. He discussed Windows Phone 7, MonoTouch for iOS, and MonoDroid for Android. He covered code reuse across platforms using libraries like Json.Net and FlickrNet. He demonstrated a Twitter app built with each platform. Key takeaways included strategies for porting code between platforms and leveraging common .NET APIs while working around platform limitations.

1. WP7, iPhone,Android
Oh my!
Chris Hardy
Modern .NET day
Reading 23rd October 2010

2. Chris Hardy
• ASPInsider
• Mobile is my hobby
• http://twitter.com/chrisntr

3. http://greatfridays.com

4. http://emmawatson.com

5. http://dominion-funds.com

6. Covering...
• Windows Phone 7
• MonoTouch
• MonoDroid
• Code reuse
• Porting code
• Demos

7. Windows Phone 7
•Windows Only
•Visual Studio 2010 / Expression Blend 4
• Silverlight for Windows Phone...
• Great information for developers

8. MonoTouch
• Mac only
• MonoDevelop
•Apple’s Interface Builder
• Superset of Silverlight 3
• Good community around

9. MonoDroid(currently in preview form)
• Cross platform
•Visual Studio 2010 / MonoDevelop
• XML Files / DroidDraw
• Superset of Silverlight 3
• Early days

10. Windows Phone 7
• Metro
• Panorama/Pivot
• Launchers/Choosers
• Tombstoning

11. Metro
http://crocusgirl.wordpress.com/

12. Panorama/Pivot

13. Launchers/Choosers
• CameraCaptureTask
• EmailAddressChooserTask
• MarketplaceHubTask
• PhoneCallTask
• PhotoChooserTask
• SearchTask
• SmsComposeTask

14. Tombstoning
sort of multi-tasking

15. Demo
Twitter on Windows Phone 7

16. http://www.youtube.com/watch?v=CZcS5PYG9kw
Twitter on Windows Phone 7

17. What is MonoTouch?

18. What is Mono?
The .Net Framework
created by Miguel De Icaza
et al.

19. Miguel de Icaza

20. Mono’s JIT Engine
CIL
Mono
Memory

21. Apple Rules
• Contractual Requirements
• No interpreted code
• No shared libraries
• Kernel Limitations
• iPhone OS 2.0+ disables JIT

22. Mono’s AOT Engine
CIL
Mono
AOT Mono Runtime
ARM
Native
Code

23. MonoTouch Features
• mtouch
• MonoDevelop iPhone Add-In
• CocoaTouch.NET / monotouch.dll
• Full static AOT compiler
• Support for all your existing code
• Reflection
• Generics
• LINQ
• Anonymous Methods
• Lambda’s etc...

24. MonoTouch’s APIs

25. The Bindings
• MonoTouch namespace
• MonoTouch.Foo namespace
• Maps to CocoaTouch’s Foo Framework
• 1:1 Mapping of classes.
• MonoTouch.UIKit.UILabel
• CocoaTouch’s UIKit framework, UILabel
class

26. Strong Types
• Objective-C
• Arrays are weakly typed:
• NSArray return values.
• MonoTouch has strong types
• UIView[] Subviews { get; }
• vs
• NSArray *subviews;
• Intellisense - explore the API...

27. Garbage Collection
• Automatic:
• Mono’s GC will collect objects on demand
• Deterministic:
• Use when you need control.
• Every object in MonoTouch implements IDisposable
using (var image = UIImage.FromFile(“foo.png”)){
surface.DrawImage(image, 20, 20);
}

28. Linker
and the application size...

29. Linking Assemblies

30. App-store MonoTouch
Minimum App Size
~6MB

31. Integration
• Tight integration between MD and IB
• IB produces XIBs with MD parses
• Automatic class generation in MD
• Generates partial classes for all types,
outlets and actions defined in Interface
Builder

32. MonoTouch Events
• Supports Objective-C pattern:
webView.Delegate = new
MyWebViewDelegate();
• C# style events as well:
webView.PageLoaded += delegate {
HideSpinningWheel();
}

33. Debugging
• Console.WriteLine(“Debugging inside of
MonoTouch”);
• printf(“I made it to this line!n”)

34. Debugger
• MonoTouch debugger leverages Mono’s
new Soft-Debugger
• Supports the Simulator
• Supports the Device...
• even over WiFi

35. Professional iPhone
Programming with
MonoTouch and .NET/
C#
Wallace B. McClure
Rory Blyth
Martin Bowling
Craig Dunn
and me... Chris Hardy
Out Now!

36. Demo
Twitter on iPhone with MonoTouch

37. Twitter on iPhone with MonoTouch
Will probably do a video in the future :)

38. What is MonoDroid?

39. What is MonoDroid?

40. What is MonoDroid?
C# on Android

41. What is MonoDroid?
A commercial product

42. What is MonoDroid?
Preview release
Not Alpha
Not Beta

43. What is MonoDroid?
Cross-platform

44. What is MonoDroid?
Sign-up for preview
access
http://go-mono.com/monodroid/

45. Demo
Twitter on Android with MonoDroid

46. Twitter on Android with MonoDroid
http://www.youtube.com/watch?v=TKXgugOj56I

47. Application Stores

48. Windows Phone 7
$99 PerYear
iPhone
$99 PerYear
Android
$25 Registration

49. Code reuse

50. Code reuse
Json.Net
FlickrNet
XNATouch

51. Rebuild your libraries
• Can’t just use any DLL
• Re-compile for each lib
• Each framework has its own class library

52. Not an abstraction!

53. Not an abstraction!
• Platform specific APIs
• Platform specific look and feel

54. Mono for WP7?

55. Mono for WP7?
• Look at Mono code and copy over!
• IQueryable support in WP7
• More later...

56. Porting over
Hanselminutes

57. Porting over
Hanselminutes
hanselminutesiphone.codeplex.com

58. Porting over
Hanselminutes
• Make sure your business logic is separate
• Use actions for returning results

59. Getting XML

60. Persisting the XML

61. Isolated Storage
vs
File Storage

62. Storing data
void SaveLocal(string data)
{
#if (MonoTouch || MonoDroid)
File.WriteAllText(_localPath, data);
#elif WINDOWS_PHONE
using (var appStorage =
IsolatedStorageFile.GetUserStoreForApplication())
{
var file = appStorage.OpenFile(_localPath, FileMode.Create);
FileExtension.WriteAllText(file, data);
}
#endif
}

63. Storing data
void SaveLocal(string data)
{
#if (MonoTouch || MonoDroid)
File.WriteAllText(_localPath, data);
#elif WINDOWS_PHONE
using (var appStorage =
IsolatedStorageFile.GetUserStoreForApplication())
{
var file = appStorage.OpenFile(_localPath, FileMode.Create);
FileExtension.WriteAllText(file, data);
}
#endif
}

64. No File.WriteAllText?
No problem!

65. Implementing
File.WriteAllText
public static void WriteAllText(IsolatedStorageFileStream fileStream, string data)
{
using (StreamWriter sw = new StreamWriter(fileStream))
{
sw.Write(data);
sw.Close();
}
}
public static void WriteAllText(string path, string contents)
{
WriteAllText(path, contents, Encoding.UTF8);
}
public static void WriteAllText(string path, string contents, Encoding encoding)
{
using (StreamWriter sw = new StreamWriter(path, false, encoding))
{
sw.Write(contents);
}
}

66. Limited WebClient calls

67. Downloading a file -
MonoTouch
_webClient = new WebClient ();
_webClient.DownloadFileCompleted += (sender, e) =>
{
_fileDownloaded = true;
if (_downloadCompletedSuccessfully) {
File.Copy (_show.PartialAudioPath, _show.OfflineAudioPath);
}
UIHelper.StopInternetActivity ();
};
_webClient.DownloadProgressChanged +=
HandleClientDownloadProgressChanged;
_webClient.DownloadFileAsync (new Uri (_show.Url), _show.PartialAudioPath);

68. Downloading a file WP7
var client = new WebClient();
client.DownloadProgressChanged += (s, e) =>
{
progressBar1.Value = e.ProgressPercentage / 100;
};
client.OpenReadCompleted += (s, e) =>
{
using (var isoStore = IsolatedStorageFile.GetUserStoreForApplication())
using (var fs = new IsolatedStorageFileStream(CurrentShow.OfflineAudioPath,
FileMode.Create, isoStore))
{
int bytesRead;
byte[] bytes = new byte[1024 * 1024 * 1]; // 1meg
while ((bytesRead = e.Result.Read(bytes, 0, bytes.Length)) != 0)
{
fs.Write(bytes, 0, bytesRead);
}
_fileDownloaded = true;
fs.Flush();
}
};
client.OpenReadAsync(new Uri(CurrentShow.Url, UriKind.Absolute));

69. Porting your code
• MOMA for Mobile?

70. Conclusions

71. Thanks! Any questions?
twitter.com/chrisntr
chrisntr@gmail.com