Click through in order to find out a practical solution to fighting the monster which is UI View Controller. The code used for the demo: https://github.com/yopeso/FightingMonster Watch the video here: https://www.youtube.com/watch?v=QaYB2S5djV8

1. Andrei Raifura iOS Department Manager, YOPESO
#CodeWăy
UIViewController:
Fighting the monster

2. Overview
• The“monster”problem
• A practical solution
• View Controllers from historical perspective

3. Historical approach

4. Historical approach

5. Historical approach

6. Meet UIViewController
• Contains the View
• Manages the View
• Plays well with Interface Builder
• Defines a screen
• Conforms to MVC

7. Conceptual MVC
Model View
Controller
Update
Update
User ActionNotify

8. ViewController’s MVC
Model ViewController
View
Update
Notify

9. Meet UIViewController

10. The problem

11. Things changed

12. ViewController is the same (almost)
Model ViewController
View
Update
Notify

13. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

14. View setup
@interface FMViewController ()
@property (weak, nonatomic) IBOutlet UITextField *usernameTextField;
@property (weak, nonatomic) IBOutlet UITextField *passwordTextField;
@property (weak, nonatomic) IBOutlet UIView *feedbackView;
@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *activityIndicator;
@end
@implementation FMViewController

15. View setup
- (void)viewDidLoad {
[super viewDidLoad];
self.myButton.titleLabel.font = myCustomFont;
UIImage *stretchableImage =
[self.myButton setBackgroundImage:stretchableImage
forControlState:UIControlStateNormal];
}

16. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

17. View layout
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.myLabel.frame = /* ... */
self.myButton.frame = /* ... */
}

18. View layout

19. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

20. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

21. Navigation logic
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
id item = [self itemAtIndexPath:indexPath];
DetailsViewController *detailsVC
= [[DetailsViewController alloc] initWithItem:item];
[self.navigationController pushViewController:detailsVC
animated:YES];
}

22. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

23. Core Data code
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

24. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

25. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

26. Decision making code
DetailsViewController *detailsVC = /* ... */;
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
// display details in the split view controller's
// details pane
} else {
// push details to the current navigation controller
}

27. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

28. iOS Architecture

29. Looking into a View Controller

30. Looking for a solution

31. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

32. ViewController’s Responsibilities
• View layout
• View management code
• Navigation logic
• View setup
• Core Data and NSFetchedResultsController code
• Delegate methods
• Other“decision making”code

33. Demo

34. Reduced Responsibilities
• View layout
• View management code
• View setup

35. View Controller issues
• Cannot be tested (using unit tests)
• Requires changes when the UI is changed

36. ViewController’s MVC
Model ViewController
View
Update
Notify

37. ViewController’s MVC
ViewController
View

38. ViewController’s MVC
ViewController View
Update
User Action

39. Demo

40. • Use View Models to encapsulate the information the view displays
• Put the IBOutlets in the private interface
• Create classes for views
• Use XIBs to define your layout
• Use a delegate to communicate asynchronous events from the view
• View keeps the datasources
Separate View from View Controller

41. • Testable View Controllers
• Ability to change the View without touching the View Controller
• More granular code
• It plays well with MVVM and VIPER concepts
Advantages

42. • Cannot use storyboards
• May lead to class explosion
• Requires some glue code
Disadvantages

43. One more thing?

44. Summary
• The“monster”problem
• A practical solution
• View Controllers from historical perspective

45. Questions?

46. Contacts
Raifura Andrei
iOS Department Manager, YOPESO
andrei.raifura@yopeso.com
thelvis4@gmail.com
#CodeWăy