1. NSSpain 2015
Soroush Khanlou

3. Overstuffed App Delegate

4. @interface SKTabBarController : UITabBarController

5. Model-View Binding
Model Mutation
Navigation FlowLayout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER

6. — Graham Lee
When you get overly attached to MVC, then
you look at every class you create and ask the
question “is this a model, a view, or a
controller?”. Because this question makes no
sense, the answer doesn’t either: anything that
isn’t evidently data or evidently graphics gets
put into the amorphous “controller” collection,
which eventually sucks your entire codebase
into its innards like a black hole collapsing
under its own weight.

7. — Graham Lee
When you get overly attached to MVC, then
you look at every class you create and ask the
question “is this a model, a view, or a
controller?”. Because this question makes no
sense, the answer doesn’t either: anything that
isn’t evidently data or evidently graphics gets
put into the amorphous “controller” collection,
which eventually sucks your entire codebase
into its innards like a black hole collapsing
under its own weight.

8. — Graham Lee
When you get overly attached to MVC, then
you look at every class you create and ask the
question “is this a model, a view, or a
controller?”. Because this question makes no
sense, the answer doesn’t either: anything that
isn’t evidently data or evidently graphics gets
put into the amorphous “controller” collection,
which eventually sucks your entire codebase
into its innards like a black hole collapsing
under its own weight.

9. Model-View Binding
Model Mutation
Navigation FlowLayout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER

10. Controller
User Input
Model
Domain State
View
Display and Layout

11. Adapter
Mediates Model-View Interaction
Model
Domain State and Behavior
View
Display and Layout
Mutate
Update View
Notify
User Action

12. View Controller
Mediates Model-View Interaction
Model
Domain State and Behavior
View
Display and Layout
Mutate
Update View
Notify
User Action

13. - (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
id object = [self.dataSource objectAtIndexPath:indexPath];
DetailViewController *detail =
[[DetailViewController alloc] initWithObject:object];
[self.navigationController pushViewController:detail animated:YES];
}

14. - (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
id object = [self.dataSource objectAtIndexPath:indexPath];
DetailViewController *detail =
[[DetailViewController alloc] initWithObject:object];
[self.navigationController pushViewController:detail animated:YES];
}

15. - (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
id object = [self.dataSource objectAtIndexPath:indexPath];
DetailViewController *detail =
[[DetailViewController alloc] initWithObject:object];
[self.navigationController pushViewController:detail animated:YES];
}

16. - (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
id object = [self.dataSource objectAtIndexPath:indexPath];
DetailViewController *detail =
[[DetailViewController alloc] initWithObject:object];
[self.navigationController pushViewController:detail animated:YES];
}

17. PhotoSelectionViewController
StraighteningViewController
FilteringViewController
CaptionViewController

18. Frameworks
vs
Libraries

19. Frameworks call you
vs
Libraries

20. Frameworks call you
You call
vs
Libraries

21. UIView
UIViewController

22. UIView
UIViewController
CALayer

23. UIView
UIViewController
CALayer
???

24. UIView
UIViewController
CALayer
Coordinators

25. App Coordinator

26. App Coordinator
aka Application Controller

27. What does a coordinator do?

28. Model-View Binding
Model Mutation
Navigation FlowLayout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

29. Model-View Binding
Model Mutation
Navigation FlowLayout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

30. Model-View Binding
Model Mutation
Navigation Flow
Layout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

31. Model-View Binding
Model Mutation
Navigation Flow
Layout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

32. Model-View Binding
Model Mutation
Navigation Flow
Layout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

33. Model-View Binding
Model Mutation
Navigation Flow
Layout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

34. Model-View Binding
Model Mutation
Navigation Flow
Layout
Subview Allocation
User Input
Data Transformation
Data Fetching
VIEW CONTROLLER
COORDINATOR
VIEW MODEL

35. How do you make a coordinator?

36. - (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)options {
self.window = [UIWindow new];
self.rootViewController = [UINavigationController new];
self.coordinator = [[AppCoordinator alloc]
initWithNavigationController:self.rootViewController];
[self.appCoordinator start];
[self.window makeKeyAndVisible];
}

37. - (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)options {
self.window = [UIWindow new];
self.rootViewController = [UINavigationController new];
self.coordinator = [[AppCoordinator alloc]
initWithNavigationController:self.rootViewController];
[self.appCoordinator start];
[self.window makeKeyAndVisible];
}

38. - (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)options {
self.window = [UIWindow new];
self.rootViewController = [UINavigationController new];
self.coordinator = [[AppCoordinator alloc]
initWithNavigationController:self.rootViewController];
[self.appCoordinator start];
[self.window makeKeyAndVisible];
}

39. - (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)options {
self.window = [UIWindow new];
self.rootViewController = [UINavigationController new];
self.coordinator = [[AppCoordinator alloc]
initWithNavigationController:self.rootViewController];
[self.appCoordinator start];
[self.window makeKeyAndVisible];
}

40. @interface AppCoordinator : NSObject

41. - (instancetype)initWithNavigationController:
(UINavigationController *)navigationController {
self = [super init];
if (!self) return nil;
_navigationController = navigationController;
return self;
}

42. - (void)start {
if ([self isLoggedIn]) {
[self showContent];
} else {
[self showAuthentication];
}
}

43. - (void)showAuthentication {
AuthCoordinator *authCoordinator =
[[AuthCoordinator alloc]
initWithNavigationController:
self.navigationController];
authCoordinator.delegate = self;
[authCoordinator start];
[self.childCoordinators addObject:authCoordinator];
}

44. - (void)coordinatorDidAuth:(AuthCoordinator *)coordinator {
[self.childCoordinators removeObject:coordinator];
[self showContent];
}

45. @implementation AuthCoordinator
- (instancetype)initWithNavigationController:
(UINavigationController *)navigationController {
self = [super init];
if (!self) return nil;
_navigationController = navigationController;
return self;
}

46. - (void)start {
FirstRunViewController *firstRun =
[FirstRunViewController new];
firstRun.delegate = self;
[self.navigationController
pushViewController:firstRun
animated:NO];
}

47. - (void)firstRunViewControllerDidTapSignup:
(FirstRunViewController *)firstRun {
SignUpViewController *signup =
[[SignUpViewController alloc] init];
signup.delegate = self;
[self.navigationController
pushViewController:signup
animated:YES];
}

48. - (void)signUpViewController:(SignUpViewController *)signup
didTapSignupWithEmail:(NSString *)email
password:(NSString *)password {
//...
}
Etc.

49. Why are coordinators great?

50. 1. View controllers are isolated

51. A B C D

52. A B C D
Coordinator

53. 1. View controllers are isolated
2. View controllers are reusable

54. 1. View controllers are isolated
2. View controllers are reusable
3. Every task is encapsulated

55. 1. View controllers are isolated
2. View controllers are reusable
3. Every task is encapsulated
4. Display-binding is separate from side effects

56. 1. View controllers are isolated
2. View controllers are reusable
3. Every task is encapsulated
4. Display-binding is separate from side effects
5. Coordinators are fully in your control

58. App
Coordinator
Auth
Coordinator
Content
Coordinator
Create Profile
Coordinator
Choose Image
Coordinator
Create Message
Coordinator
Edit Profile
Coordinator
Choose Image
Coordinator
Choose Image
Coordinator

59. App
Coordinator
Auth
Coordinator
Content
Coordinator
Create Profile
Coordinator
Choose Image
Coordinator
Create Message
Coordinator
Edit Profile
Coordinator
Choose Image
Coordinator
Choose Image
Coordinator

60. App
Coordinator
Auth
Coordinator
Content
Coordinator
Create Profile
Coordinator
Choose Image
Coordinator
Create Message
Coordinator
Edit Profile
Coordinator
Choose Image
Coordinator
Choose Image
Coordinator

61. Thanks!
@khanlou