Reactive cocoa 101¸Ä
- 1. ReactiveCocoa 101¸Ä Hai Feng Kao 1
- 5. Why is debugging difficult?
- 6. Functional Programming ¡ñ Lambda Calculus ¡ñ Functions without side effects ¡ñ Programs as function compositions (y = f(g(h(x))))
- 7. Functional Reactive Programming ¡ñ In functional programming, things get hard because functions can¡¯t have side-effects o Every time a function is called, it must return the same y for same x o y = f(x) ¡ñ In functional reactive programming, time is an implicit parameter (no monads) o y = f(x, t)
- 8. ReactiveCocoa ¡ñ A open source FRP framework developed by Github o iOS / OSX o MIT License o 3.0 supports swift o https://github.com/ReactiveCocoa/Reacti veCocoa
- 9. Signals ¡ñ Primary data source of FRP ¡ñ Signals send values over time until they complete o A signal never sends anything after completing or erring o A signal either completes, or errors out, but never both
- 10. Signals(cont.) ¡ñ A signal has no concept of a ¡°current value¡± or ¡°past value¡± ¡ñ It¡¯s like a pipe ¡ñ Signals can be chained to transform the values o This is core to FRP: data transformation of values sent over time o y = f(g(h(x)))
- 11. KVO Example
- 12. Reactive Example
- 13. RACSignals ¡ñ always send id, not primitives o NSInteger -> NSNumber o CGRect -> NSValue
- 14. Functional Programming ¡ñ The building blocks of functional world o map, reduce, filter
- 15. Map ¡ñ Mapping performs a value transformation on the given signal o It ¡±maps¡± each value sent along the signal to a new value o It then passes that new value along, creating a new signal
- 16. Example
- 17. ¡ñ Combines two or more signals¡¯ values into one o Useful for waiting for conditions to be met o Useful for deciding between values Reduce
- 18. Example
- 19. Filter ¡ñ Filtering allows values that pass some test to ¡°pass through¡±
- 20. Example
- 21. Functional Programming ¡ñ The building blocks of functional world o map, reduce, filter
- 22. Functional Programming ¡ñ The building blocks of functional world o map, reduce, filter USELESS?
- 23. Bindings ¡ñ Bindings can bind a property to the latest value sent on a signal ¡ñ All bindings created with the RAC macro are one-way ¡ñ Bindings are the secret sauce that hold apps together
- 24. Example
- 26. MVC (Model View Controller) 26 ModelView Controller Input Update Update Notify
- 27. MVC (Model View Controller) ? Pros : ? Independent module ? Reusable model ? Cons: ? too may files ? hard to write unit test ? controller need to access view&model 27
- 28. ¶Uʦ-Áåľ¿¡Â¡
- 29. MVVM(Model View ViewModel) 29 ModelView ViewModel Input Update
- 30. MVVM(Model View ViewModel) ? Pros: ? ViewModel can be unit tested ? ViewModel has no access to view ? Model has no access to ViewModel ? View is simple ? UI logic moved to ViewModel ? Cons: ? hard to debug ? performance hit!!! 30
- 31. MVVM(Model View ViewModel) 31 ModelView ViewController ViewModel ReactiveCocoa
- 32. Demo 32
- 33. Reference ¡ñ Ash Furrow Reactive Cocoa 101 o https://www.youtube.com/watch?v=TlgU WYrQ0sc ¡ñ Functional Reactive Programming on iOS o https://leanpub.com/iosfrp/
- 34. Q&A