RxSwift Intro

Transcript

1. RX INTRODUCTION JJ LIN 2018.09.08
2. Rx Introduction • Why Rx • Basic concepts • Creating Observables • Wrapping API call • Dispose bag • Operators • How to make concurrent / serial API calls using Rx
3. Why Rx Let’s start from a small example
4. Why Rx Super fast solution
5. Why Rx Extract common function (Of Course!)
6. Why Rx MVVM - Testable!
7. Why Rx Remove call back by KVO?
8. Why Rx Observe one is ok, how about two?
9. Why Rx Let’s meet RxSwift
10. Basic concepts • Observable is equivalent to Sequence • Sequence in Swift: 
 A type that provides sequential, 
 iterated access to its elements.
11. Basic concepts • Observables and observers (aka subscribers) • Will not execute their subscription closure unless there is a subscriber. • next* (error | completed)?
12. Creating Observables
13. Creating Observables - create custom
14. Creating Observables - API
15. Dispose bag When a sequence sends the completed or error event all internal resources will be freed. To cancel production of sequence elements and free resources immediately, call dispose on the returned subscription. disposed(by: disposeBag) will automatically call dispose at deinit
16. Operators
17. Operators
18. Operators
19. Operators 1 a A 2 b error
20. FlatMap
21. FlatMapLatest The flatMapLatest operator behaves much like the standard FlatMap operator, except that whenever a new item is emitted by the source Observable, it will unsubscribe the Observable that was generated from the previously-emitted item, and begin only mirroring the current one.
22. How to make concurrent API calls
23. How to make serial API calls flatMap works same here
24. Reference https://github.com/ReactiveX/RxSwift http://rxmarbles.com/
25. FlatMap The FlatMap operator transforms an Observable by applying a function that you specify to each item emitted by the source Observable, where that function returns an Observable that itself emits items. FlatMap then merges the emissions of these resulting Observables, emitting these merged results as its own sequence. Note that FlatMap merges the emissions of these Observables, so that they may interleave. In several of the language-specific implementations there is also an operator that does not interleave the emissions from the transformed Observables, but instead emits these emissions in strict order, often called ConcatMap or something similar. http://reactivex.io/documentation/operators/flatmap.html