"Kotlin и rx в android" Дмитрий Воронин (Avito)

Rx & Single Abstract Method
Observable.just("Hello, world!")
.map(new Func1<String, Integer>() {
@Override
public Integer call(String s) {
return s.hashCode();
}
})
.subscribe(new Action1<Integer>() {
@Override
public void call(Integer i) {
System.out.println(i);
}
});
Java

public interface Func1<T, R> extends Function {
R call(T t);
}

.map(new Func1<String, Integer>() {
@Override
public Integer call(String s) {
return s.hashCode();
}
})
.subscribe(new Action1<Integer>() {
@Override
public void call(Integer i) {
System.out.println(i);
}
});
Java
.map { s -> s.hashCode() }
.subscribe { i -> println(i) }
Kotlin

.map { s -> s.hashCode() }
.subscribe { i -> println(i) }

.map { string -> string.hashCode() }
.subscribe { hashCode -> println(hashCode) }

.map { it.hashCode() }
.subscribe { println(it) }

Rx & High-Order functions
fun yourFunc(one: String, two: Func0<Int>)

fun yourFunc(one: String, two: () -> Int)

fun yourFunc(one: String, two: () -> Int)
yourFunc("Hi") { 1 }

Observable.combineLatest(one, two) { a, b -> a + b }
Observable.zip(one, two, three) { a, b, c -> a + b + c }

Rx & Data types
Observable.combineLatest(location, webResponse){ a, b -> Pair(a, b) }
.distinctUntilChanged()
.map { doSomething(it.first, it.second) }

Rx & Data types
Observable.combineLatest(location, webResponse){ a, b -> LocationAndResponse(a, b)}
.map { doSomething(it.location, it.response) }

Rx & Data types
data class LocationAndResponse(val location: Location, val response: Response)
Observable.combineLatest(location, webResponse){ a, b -> LocationAndResponse(a, b)}
.map { doSomething(it.location, it.response) }

Rx & Null Safety
var a: String = "abc"
a = null // compilation error

Rx & Null Safety
var b: String? = "abc"
b = null // ok

Rx & Null Safety
var b: String? = "abc"
b = null // ok
val l = b.length // error: variable 'b' can be null

Rx & Null Safety
if (b != null && b.length > 0)
print("String of length ${b.length}")
else
print("Empty string")

Rx & Null Safety
observable //Observable<Int?>
.filter { it != null }
.subscribe { println(it) } //Observable<Int?>

Rx & Null Safety
listOf(1, 2, 3, null) // Array<Int?>
.filter { it != null }
.forEach { println(it) } // Array<Int?>

Rx & Null Safety
listOf(1, 2, 3, null) // Array<Int?>
.filterNotNull()
.forEach { println(it) } // Array<Int?>

Rx & Null Safety
fun filterNotNull() {
}

Rx & Null Safety
fun Observable.filterNotNull() {
}

Rx & Null Safety
fun <T> Observable<T?>.filterNotNull(): Observable<T> {
}

Rx & Null Safety
fun <T> Observable<T?>.filterNotNull(): Observable<T> {
return filter { it != null } as Observable<T>
}

Rx & Null Safety
observable //Observable<Int?>
.filterNotNull()
.subscribe { println(it) } //Observable<Int> PROFIT!!!

Rx & Sealed classes
sealed class State {
class Progress() : State()
class Content(val data: Response) : State()
class Error(val error: Throwable) : State()
}

Rx & Sealed classes
stateObservable.subscribe {
when(it) {
is State.Progress -> { /* show progress */ }
is State.Content -> { it.data /* show content */ }
is State.Error -> { it.error /* show error */ }
}
}

Rx & Sealed classes
stateObservable
.filterByType(State.Content::class.java)
.subscribe { it.data }

Rx & Sealed classes
fun <T, R : T> Observable<T>.filterByType(type: Class<R>): Observable<R> =
filter { type.isInstance(it) } .map { type.cast(it) }

Rx & Operator overloading
val subscription = CompositeSubscription()
subscription.add(observable1.subscribe { ... })

operator fun CompositeSubscription.plusAssign(subscription: Subscription) = add(subscription)

subscription += observable1.subscribe { ... }
operator fun CompositeSubscription.plusAssign(subscription: Subscription) = add(subscription)

Rx & Lifecycle
View Model
UI events
Data events

RxBinding
Java
RxView.clicks(button)

RxBinding
Java
Kotlin
button.clicks()

RxBinding
Java
.subscribe(RxTextView.text(textView));
Kotlin
button.clicks()

RxBinding
Kotlin
button.clicks()
.subscribe(textView.text())
Java
.subscribe(RxTextView.text(textView));

RxLifecycle
JAVA
myObservable
.compose(RxLifecycle.bindActivity(lifecycle))
.subscribe();

RxLifecycle
KOTLIN
myObservable
.bindWithLifecycle(activity)
.subscribe {}
JAVA
myObservable
.compose(RxLifecycle.bindActivity(activity))
.subscribe();

RxLifecycle
KOTLIN
myObservable
.bindWithLifecycle(activity)
.subscribe {}
myObservable
.bindUntilEvent(activity,ActivityEvent.PAUSE)
.subscribe {}
JAVA
myObservable
.compose(RxLifecycle.bindActivity(activity))
.subscribe();

Rx & Type safe builders
model.dataStream()
.bindWithLifecycle(view)
.subscribe(dataHandleAction)
model.editIntent()
.subscribe(gotoEditAction)
model.mapData()
.subscribe(markersHandleAction)

view.bindWithLifecycle {
model.dataStream() with dataHandleAction
model.editIntent() with gotoEditAction
model.mapData() with markersHandleAction
}

observable.subscribe { /* on next here*/ }

observable.subscribe ({ /* onNext */ }, { /* onError*/ })

observable.subscribe ({ /* onNext */ }, { /* onError*/ })
observable.subscribe ({ /* onNext */ }, { /* onError*/ }, { /* onComplete*/ })

observable.subscribeWith {
onNext { }
onError { }
}

Testing Rx & Kotlin
val finiteObservable = Observable.from(arrayOf("1", "2", "3"))
val subscriber = TestSubscriber<String>()
finiteObservable.subscribe(subscriber)
subscriber.awaitTerminalEvent()
subscriber.assertValues("1", "2", "3")

Testing Rx & Kotlin
fun <T> Observable<T>.assertValues(vararg values: T) {
val subscriber = TestSubscriber<T>()
this.subscribe(subscriber)
subscriber.assertValues(*values)
}

Testing Rx & Kotlin
fun <T> Observable<T>.assertValues(vararg values: T) {
}
finiteObservable.assertValues("1", "2", "3")

Testing Rx & Kotlin
infix fun <T> Observable<T>.assertValues(values: Array<T>) {
}
finiteObservable assertValues arrayOf("1", "2", "3")

Testing Rx & Kotlin
infix fun <T> Observable<T>.shouldProduce(values: Array<T>) {
}
finiteObservable shouldProduce arrayOf("1", "2", "3")

"Kotlin и rx в android" Дмитрий Воронин (Avito)

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