MvvmCross Introduction

An introduction to MvvmCross - see video on http://www.youtube.com/watch?v=jdiu_dH3z5k

Transcript

1. MvvmCross Introduction 13th December 2012 @slodge
2. Presentation Model Represent the state and behavior of the presentation independently of the GUI controls used in the interface. http://martinfowler.com/eaaDev/PresentationModel.html
3. In 2005… Model/View/ViewModel is a variation of Model/View/Controller that is tailored for modern UI development platforms where the View is the responsibility of a designer rather than a classic developer. Tales from the Smart Client, John Grossman http://blogs.msdn.com/b/johngossman/archive/2005/10/08/478683.aspx
4. Also in 2005… • 10 years of dev – C++, C, VB, Java, JavaScript, LISP, SmallTalk, Delphi, … • A year off travelling – from Argentina to Zambia • DeveloperDeveloperDeveloper • 1 conclusion:
5. MvvmCross Introduction 13th December 2012 @slodge Evolving the dinosaur
6. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
7. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
8. M-V-VM
9. Detailed flow
10. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
11. ViewModels Public Properties private bool _isSearching; public bool IsSearching { get { return _isSearching; } set { _isSearching = value; RaisePropertyChanged("IsSearching"); } }
12. For ViewModel Changes public interface INotifyPropertyChanged { event PropertyChangedEventHandler PropertyChanged; } public class PropertyChangedEventArgs : EventArgs { public string PropertyName { get; } }
13. For Collections public interface INotifyCollectionChanged { event NotifyCollectionChangedEventHandler CollectionChanged; } public enum NotifyCollectionChangedAction { Add, Remove, Replace, Move, Reset, } public class NotifyCollectionChangedEventArgs : EventArg { public NotifyCollectionChangedAction Action { get; } public IList NewItems { get; } public IList OldItems { get; } public int NewStartingIndex { get; } public int OldStartingIndex { get; } }
14. For Actions public interface ICommand { event EventHandler CanExecuteChanged; bool CanExecute(object parameter); void Execute(object parameter); }
15. .Net Implementation ICommand Public Property Set INotifyPropertyChanged INotifyCollectionChanged Public Property Get
16. Why? To Enable • Awesome UI and Data Development • Unit Testing of code • Large applications to have a common architecture • Different platforms can share code
17. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
18. What is MvvmCross? Code!
19. Code evolution I • Single Mono for Android Project • Good separation of UI from ‘Model’ code • Simple – it works • But: – No testing – No testability – Portability by cut/paste
20. Code Evolution 2 • MvvmCross Library switched in – PCL code – Formal DI/IoC used • On UI: – DataBinding arrived – Code got much thinner! – XML got bigger • Not all win: – External Dependencies got larger – Code overall increased in size
21. Code Evolution 3 • Cross Platform • All UIs MVVM • 100% shared application logic • 100% shared test harness
22. Data-Binding WP/WinRT 99% Xaml Droid Mainly Axml Some .Dialog Touch Some .Dialog Some .XIB Some C#
23. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
24. Portable Class Libraries
25. Unit Testing “I get paid for code that works, not for tests, so my philosophy is to test as little as possible to reach a given level of confidence. … When coding on a team, I modify my strategy to carefully test code that we, collectively, tend to get wrong.” Kent Beck http://stackoverflow.com/questions/153234/how-deep-are-your-unit-tests
26. Plugin – Native abstractions public interface IMvxComposeEmailTask { void ComposeEmail(string to, string cc, string subject, string body, bool isHtml); } protected void ComposeEmail(string to, string subject, string body) { Cirrious.MvvmCross.Plugins.Email.PluginLoader.Instance.EnsureLoaded(); var task = this.GetService<IMvxComposeEmailTask>(); task.ComposeEmail(to, null, subject, body, false); } public class MvxComposeEmailTask : MvxWindowsPhoneTask, IMvxComposeEmailTask { public void ComposeEmail(string to, string cc, string subject, string body, bool isHtml) { var task = new EmailComposeTask() { To = to, Subject = subject, Cc = cc, Body = body }; DoWithInvalidOperationProtection(task.Show); } } 1. Declare common functionality (an interface) 2. Write platform specific implementations 3. In apps, use the interface and not the implementation
27. Sphero – Plugin Magic • Plugin Magic • Each Plugin: – 1 PCL – 1 Assembly per platform
28. Why? To Enable • Awesome UI and Data Development • Unit Testing of code • Large applications to have a common architecture • Different platforms can share code
29. What we’ll cover… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
30. MonoCross
31. A team in a galaxy far far away @imaji @mrlacey @sichy @slodge @touch4apps …
32. Redth in Canada https://github.com/Redth/WshLst/
33. Rune in Norway https://github.com/runegri/CrossBox
34. Jason in UK http://www.aviva.co.uk/drive/
35. CheeseBaron in Denmark http://blog.ostebaronen.dk/
36. Greg in NYC http://bit.ly/mvxgshac
37. JSON.Net Downunder (?)
38. Olivier in France http://www.e-naxos.com/UsIndex.html
39. Dan in Italy http://bit.ly/mvxDanA
40. Zoldeper in Hungary? https://github.com/Zoldeper/Blooor
41. Daniel in Redmond http://channel9.msdn.com/Events/Build/2012/3-004
42. What we’ve covered… • MVVM Theory • .Net MVVM • A practical example – some code! • Interface Driven Development – Portable Class Libraries – Unit Testing – Plugins • Some examples
43. To join in… • Tool up • Share • Reuse • Test • Architect If you want to join in:
44. MS-PL on GitHub http://github.com/slodge/MvvmCross
45. Some other talks available http://bit.ly/mvxTweetPic
46. C# - 1 Stack - Cloud to Mobile WP7 iOS Droid Win8 Data Access Business Logic Presentation Service Consumption Business Logic Local Data/Services UI Logic
47. Not as cool as dinosaurs WP7 iOS Droid Win8 Data Access Business Logic Presentation Service Consumption Business Logic Local Data/Services UI Logic
48. Some credits Images from Wikipedia Commons: • http://en.wikipedia.org/wiki/File:Macronaria_scrubbed_enh.jpg • http://en.wikipedia.org/wiki/File:Human- eoraptor_size_comparison%28v2%29.png Diagrams from Java – ZK • http://books.zkoss.org/wiki/ZK_Developer%27s_Reference/MVVM Sample projects as credited inline
49. Thanks for listening… http://cirrious.com http://slodge.blogspot.com http://github.com/slodge/mvvmcross me@slodge.com @slodge Stuart Lodge, I’m a Dinosaur
50. Xamarin Seminar 13th December 2012 Please give us your feedback Follow us on Twitter http://bit.ly/xamfeedback @XamarinHQ