A gentle introduction to Kotlin Coroutines Arturo Mejia Twitter: @ArturoMejia481 ArturoMejiaMarmol.com 

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Alternatives @ArturoMejia481 Threads Callbacks RX (Reactive extensions) Futures Promises 

Threads @ArturoMejia481 Expensive, not easy to use. IOS deprecate threads. DispatchQueue 

Callbacks @ArturoMejia481 Don't call me, I'll call you! 

Callbacks @ArturoMejia481 Callback Hell 

Callbacks @ArturoMejia481 Callback Hell a.k.a Tilted Christmas Tree. 

Callbacks @ArturoMejia481 Difficult error handling. 

Promises and Futures @ArturoMejia481 

Reactive Extensions @ArturoMejia481 You have to change the way that you approach a problem. Operators RX Schedulers Streams 

@ArturoMejia481 Reactive Extensions 

@ArturoMejia481 Kotlin Coroutines Do async work the same way, exceptions, loops, etc… 

@ArturoMejia481 Kotlin Coroutines Clear differences between suspend functions 

@ArturoMejia481 Kotlin Coroutines Same function signature 

Coroutines = Lightweight @ArturoMejia481 Threads Coroutines 

@ArturoMejia481 Kotlin Coroutines 

Goal @ArturoMejia481 Suspend Dispatchers Coroutine Builders Launch Async/await 

Suspend @ArturoMejia481 A key word to indicate the compiler that a function can be suspended. 

Suspend @ArturoMejia481 A suspend function should be called from a coroutine or another suspend function. 

Suspend @ArturoMejia481 The Kotlin compiler transforms the function to a callback model and uses state machines to know when a function should be suspended or resume. 

@ArturoMejia481 Coroutine ≈ Threads 

Let’s get our hands dirty! @ArturoMejia481 

Launch @ArturoMejia481 Launch is when we want to fire and forget. 

Async @ArturoMejia481 Async is when we want to run something, then await the result. 

Dispatchers @ArturoMejia481 DEFAULT (Computational) Uses the # cores of the CPU, not good for computations like I/O, network, disk, etc. IO designed for doing blocking I/O operations, max #64 thread, share the pool with DEFAULT. MAIN designed to operate UI objects. Indicate in which thread pool a coroutine should run 

Interoperate @ArturoMejia481 kotlinx-coroutines-rx2: Utilities for Rx. kotlinx-coroutines-jdk8: Integration with JDK8 CompletableFuture (Android API level 24). kotlinx-coroutines-android: Designed to operate UI objects. 

“With a great power, comes responsibility” @ArturoMejia481 Spiderman 

Questions? @ArturoMejia481 

Thanks! Twitter: @ArturoMejia481 ArturoMejiaMarmol.com Android Tutorials RayWenderLich.com/u/amejia481