The 2nd Dnepropetrovsk iOS Practice Leaders Community Meet-Up. MVC by Dmitriy Sai, iOS developer with 3+ years of experience. The following presentation covers the issues of the practical use of Model View Controller on iOS, focusing on the principles of roles’ division, clear code, simplification of refactoring and unit-testing.

1. Design Pattern
MVC
July 17th, 2014

2. MVC

3. Agenda
● History
● MVC
● Controller specifications
● View specifications
● Model specifications
● Demo

4. History
Model View Controller (MVC) is one of the most quoted
(and most misquoted) patterns around. It started as a
framework developed by Trygve Reenskaug for the
Smalltalk platform in the late 1970s. Since then it has
played an influential role in most UI frameworks and in
the thinking about UI design.

5. MVC
● Controller sends commands to the model to update state.
Also sends commands to its associated view to change
the appearance.

6. MVC
● Controller sends commands to the model to update state.
Also sends commands to its associated view to change
the appearance.
● A model notifies its controllers when there has been a
change in its state. This notification allows the views to
produce updated output.

7. MVC
● Controller sends commands to the model to update state.
Also sends commands to its associated view to change
the appearance.
● A model notifies its controllers when there has been a
change in its state. This notification allows the views to
produce updated output.
● A view requests information from the model that it needs
for generating an output representation to the user.

8. MVC
Model specifications:
● business logic

9. MVC
Model specifications:
● business logic
● has knowledge about itself but does not know
about the controllers and views;

10. MVC
Model specifications:
● business logic
● has knowledge about itself but does not know
about the controllers and views;
● in some cases is a database manager or a set
of objects;

11. MVC
Business logic - real-world business rules that determine
how data can be created, displayed, stored, and changed.

12. Model
Model base types:
- passive model
- active model (basic type)

13. MVC
Model
ApiClient DataManager
update UI

14. MVC
@property (readonly) DPManagerProvider *provider;

15. MVC
@property (readonly) DPManagerProvider *provider;
#dynamic state
@property (readonly) NSString *email;
@property (readonly) NSString *password;
@property (readonly) NSString *messageText;
@property (readonly) BOOL canEdit;

16. MVC
@property (readonly) DPManagerProvider *provider;
#dynamic state
@property (readonly) NSString *email;
@property (readonly) NSString *password;
@property (readonly) NSString *messageText;
@property (readonly) BOOL canEdit;
#static states
@property (readonly) NSString *emailDefaultText;
@property (readonly) NSString *passwordDefaultText;
@property (readonly) NSString *title;
@property (readonly) NSString *loginTitle;

17. MVC
@property (readonly) DPManagerProvider *provider;
#dynamic state
@property (readonly) NSString *email;
@property (readonly) NSString *password;
@property (readonly) NSString *messageText;
@property (readonly) BOOL canEdit;
#static states
@property (readonly) NSString *emailDefaultText;
@property (readonly) NSString *passwordDefaultText;
@property (readonly) NSString *title;
@property (readonly) NSString *loginTitle;
#data access methods
- (void)login;
- (BOOL)shouldChangeEmailInRange:(NSRange)range
replacementText:(NSString *)text;
- (BOOL)shouldChangePasswordtInRange:(NSRange)range
replacementText:(NSString *)text;

18. MVC
ControllerModel

19. MVC
ControllerModel
● Notification

20. MVC
ControllerModel
● Notification
● KVO

21. MVC
ControllerModel
● Notification
● KVO
● Delegate

22. MVC
ControllerModel
● Notification
● KVO
● Delegate
● Binding

23. MVC
Controller specifications:
● can transmit data

24. MVC
Controller specifications:
● can transmit data
● can place Views on the screen

25. MVC
Controller specifications:
● can transmit data
● can place Views on the screen
● can respond to user’s actions

26. MVC
Controller specifications:
● can transmit data
● can place Views on the screen
● can respond to user’s actions
● can operate with several Views

27. MVC
View specifications:
● can display data

28. MVC
View specifications:
● can display data
● can, in some cases, have code that
implements some business logic

29. MVC
Controller
Model View
@ view;
@ model;

30. MVC
Controller
Model View
View

31. MVC
Controller
Model
ViewController
View

32. MVC
Controller
Model View
View
Controller

33. MVC
Controller
Model
View

34. MVC
Controller
Model
View
View
Controller
Model
@parameters

35. MVC
Controller
Model
Storyboard
Controller
Model @
parameters

36. MVC
Additional materials:
● Msdn MVC
● MVC https://developer.apple.com
● Refactoring code
http://martinfowler.com/books/refactoring.html
● Steve McKinley “Perfect Code”
● Eric Freeman “Design Patterns”

37. Demo: dima.sai github - dsay