Good Coding Practice Objective - C

Thanks to Mr: Jean-Luc David

 

Presentation Transcript

• 1. Agenda• Project Structure• Design Patterns & Architecture• Storing Data• Coding Conventions
• 2. What main design pattern doesApple recommend forstructuringyour iOS projects?
• 3. Model-View-Controller Controller Update Coordination Changes Changes Update Model Data View Display
• 4. Default Project • Notice Classes is a catch-all default ‘’bucket’’ for code
• 5. MVC Formatted Project• Remove references• Create class folders in Finder • AppDelegate • Controllers • Helpers • Models• Drag into Xcode
• 6. According to Apple, should themodel, view or controller be usedto capture events?
• 7. Roles & Responsibilities• Model • Data/Algorithms/Networking • Most of your custom code lives here• View • Display/Event Capture/Visual Appeal • Don’t try to reinvent UIKit, use it• Controller • Coordination/Delegation/Odd Jobs • Transitions, Startup/Shutdown
• 8. Is this a good pattern & why? Update
• 9. Don’t cut out the controller! Avoid bi-directional messaging Reject DelayValidate Update • Network Access • Multiple Choices • Commit
• 10. Is this a good pattern & why?
• 11. Loose Coupling• Don’t skip MVC layers when messaging • Use controllers to coordinate messages• Don’t mix MVC roles in one object • Don’t gather too much work in one place• Don’t declare data in your view classes • Maintenance nightmare • You can display data in a view, just don’t store it
• 12. What are three of the designpatterns used to communicatebetween the model, view &controller?
• 13. Communication Between Objects Target-Action Notification Delegation Reuse controls without Broadcast changes Control reuse subclassing “Yes” « When tapped, call this method » « Software keyboard “End Editing?”-setTarget:(id)target action:(SEL)action…about to appear! » UIKit (UIScrollView, ect) NSNotificationCenter Will/Did/Should -(void)scrollViewDidZoom:
• 14. How do you create a customcontroller to split the screen in twoparts?
• 15. You Don’t! Use the UISplitViewController• Don’t try to reinvent the wheel • UIKit has a lot of the base controls you need • Really question whether you need a custom control (and if it exists already)• Don’t misuse framework classes • ie Removing views from UIViewControllers• Don’t try to reinvent the way models, views & controllers talk to each other • Use delegates & notifications
• 16. Is this a good pattern & why?-(void)scrollViewDidScroll:(UIScrollView *)scrollView{ if ([scrollView isKindOfClass:[UITableView class]}){ // do something } else { // use UIScrollView logic}
• 17. Class checks in delegate methodsCode unmanagable over time - EverythingControllersCoding horror - iOS version of a GOTOCorrect Approach oniPadParcel out yourcontrollers
• 18. MANDATORY: ALWAYS write/model out your iOS app design before coding!At first, I was like… But then, it was like… (in your brain) (in the repo)
• 19. Creating an MVC diagram of your project• Means you thought through the architecture• Means you know how the code will be organized physically & logically• Means you potentially avoided structural bugs• Easier to validate with the team• High quality projects & happy clients
• 20. What’s the optimal architecture fora Universal Application?
• 21. Optimal Universal App Architecture iPhone App iPad App UI Framework (Views & Controllers) Non-UI Framework (Networking & Models)
• 22. Photo Sharing Application Data from the model is in both the inspector and in the toolbar
• 23. MVC Structure Update Change Change Update
• 24. What are the six primary ways ofstoring data on iOS?
• 25. Six Model Options• Property Lists• Archives• Custom Files• Server/iCloud/APIs• SQLite• CoreData
• 26. According to Apple, what data shouldyou store in your AppDefaults/Preferences?
• 27. Don’t store data in settings!• Wrong tool for the job• App may get rejected• Settings Panel test • On/Off Advanced Features
• 28. What should you use for quick storageofstrings, numbers, arrays, dictionaries, ect?
• 29. Property Lists.
• 30. What should you use to store partialgraphs?
• 31. CoreData• Modeling Tools• Simple save/restore• Queries• Data Protection• Ordered Relationships• UIManagedDocument• Partial Graphs• Undo• Incremental Stores• ect…
• 32. What should you use to include datawith queue-based concurrency in yourapp?
• 33. CoreData again.
• 34. What should you use if you are dealingwith a lot of legacy code or data, or youneed to create an NSObject-basedgraph?
• 35. Custom Files.
• 36. When would you want to use a dataarchive?
• 37. For easily « serializing »and « deserializing »objects in a data file.
• 38. What are the two primary features ofSQLite?
• 39. Provides Database functionality for iOS appsSupports Object Relational Mapping
• 40. Know Your Data Model Options• Property Lists• Archives• Custom Files• Server/iCloud/APIs• SQLite• CoreData
• 41. Coding Conventions • Brace style for if-else • Parenthesis style • Leading underscores • Code indenting • CapitalizationStyle (ie capitalization_style) Check out the Google iOS Style guide & Apple docs: http://google- styleguide.googlecode.com/svn/trunk/objcguide .xml
• 42. What is KVO?
• 43. Key-Value Observing (KVO) • Requires your code to be compliant • Follow style guide • Instrument your own notifications • Automatic Change Notifications for your objects