So long, Flow Controller

Presented at CocoaHeads Montreal on September 26th, 2019.

Transcript

1. So long, Flow Controller Olivier Collet. CocoaHeads Montreal. 26.09.2019
2. The Story
3. December 2012
 Seb Morel presents at CocoaHeads Montreal:
 “How to Avoid the Flying Spaghetti Code Monster!”
4. Flow Manager MVC Intent 1. Get Model 2. Setup Flow Dependent Elements 3. Presents MVC Intent 1. Get Model 2. Setup Flow Dependent Elements 3. Presents MVC Intent 1. Get Model 2. Setup Flow Dependent Elements 3. Presents MVC Intent 1. Get Model 2. Setup Flow Dependent Elements 3. Presents MVC Intent 1. Get Model 2. Setup Flow Dependent Elements 3. Presents
5. January 2014
 CocoaHeads Paris:
 “Flow Controller”
6. February 2014
 Blog post:
 “Give Your App a Brain With a Flow Controller”
7. January 2015
 Soroush Khanlou writes a blog post:
 “The Coordinator”
8. February 2016
 CocoaHeads Montreal:
 “Flow Controller - Revisited”
9. Flow Controller 1. Keep the application’s state 2. Manage the logic between view controllers 3. Orchestrate the view controllers 4. Prevent view controller dependencies 5. Handle a portion of the application
10. Flow Controller
11. Flow Controller ☠ DEAD
12. Best code is no code.
13. Inherits from UIResponder with a reference to a root UIViewController Inherits from UIViewController UINavigationController, UITabBarController, or custom container view controller
14. View controllers report via delegate with lots of delegate protocols in a complex view controller hierarchy View controllers report via the responder chain low key introducing the Event and EventHandler protocols
15. Event + EventHandler
16. Event
 protocol • Similar to Error
 Can be used as an enum with associated values 
 or as a struct with properties • Passed along the responder chain
 
 protocol Event { }
17. EventHandler
 protocol • Implement to receive Events • Specifies the event that can keep being propagated
 down the responder chain or no event to propagate protocol EventHandler: AnyObject { func handleEvent(_ event: Event) -> Event? }
18. UIResponder
 extension • func postEvent(_ event: Event)
 propagates the event up the responder chain • var eventHandler: EventHandler?
 can be used to hook an object that is not part of the responder chain

19. Annie Spratt
20. References • https://github.com/smorel/CocoaHeads-Avoiding-Spaghetti-Code/ blob/master/cocoaheads%20- %20How%20to%20avoid%20the%20spaghetti%20code%20Monster.pd f • https://speakerdeck.com/ocollet/flow-controller-give-your-app-a-brain • https://ocollet.com/2014/02/06/flow-controller/ • http://khanlou.com/2015/01/the-coordinator/ • https://speakerdeck.com/ocollet/flow-controller-revisited • https://gist.github.com/ocollet/719216edad74a5135470cf508bf50277
21. Olivier Collet
 @ocollet ✌