RxJava vs Coroutines

Transcript

Kotlin Coroutines ve RxJava
kullanım senaryoları
Hadi Tok
Lead Android Dev @CitizenMe

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Data layer
Business Logic Layer
UI Layer
Observable (Single, Completable, Maybe)
I/O (Network-File-DB)

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Data layer
UI Layer

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Data layer
UI Layer

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Coroutines
! Kod akışının belirli bir noktada duraklatılıp
paraleldeki başka bir işin tamamlanmasından sonra
devam edebilmesi
! Hafif siklet (lightweight) thread
! Geçtiğimiz hafta stable release olarak yayınlandı

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Senaryo #1 Basit
asenkron iş

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private fun readFile(name: String): String {
return assets.open(name).bufferedReader().use { it.readText() }
}

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Coroutines

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GlobalScope.launch(Dispatchers.Main) {
textView.text = readFile("thefile.txt")
}

}

}

}

}

}

textView.text = async(Dispatchers.IO) { readFile(“thefile.txt") }.await()
}

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val deferred: Deferred = async(Dispatchers.IO) {
readFile("thefile.txt")
}
val string: String = deferred.await()
textView.text = string
}

}
}

}
}

}
}

}
}

}
}

RxJava

Single.create { singleEmitter ->
val string = readFile("thefile.txt")
singleEmitter.onSuccess(string))
}.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe { string ->
}

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}

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}

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singleEmitter.onSuccess(readFile("thefile.txt")))
}

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RxJava Error
Handling

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.subscribe({ string ->
}, { e ->
if (e is IOException) {
handleIOException(e)
}
})

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.subscribe({ string ->
}, { e ->
}
})

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Coroutines Error
Handling

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try {
textView.text = async(Dispatchers.IO) {
}.await()
} catch (e: IOException) {
}
}

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try {
}.await()
}
}

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RxJava Android
lifecycle

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val disposable = Single.create {…}
.subscribeOn(Schedulers.io())
.subscribe({…}, {…})
compositeDisposable.add(disposable)
override fun onDestroy() {
super.onDestroy()
compositeDisposable.dispose()
}

super.onDestroy()
}

super.onDestroy()
}

super.onDestroy()
}

Coroutines Android
lifecycle

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class MainActivity : AppCompatActivity() , CoroutineScope {
private lateinit var job: Job
override val coroutineContext: CoroutineContext
get() = Dispatchers.Main + job
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
job = Job()
}
super.onDestroy()
job.cancel()
}
}

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job = Job()
}
super.onDestroy()
job.cancel()
}
}

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job = Job()
}
super.onDestroy()
job.cancel()
}
}

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try {
}.await()
}
}

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launch{
try {
}.await()
}
}

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Senaryo #2 iki asenkron işin sonuçlarını birleştirme
! Paralelde çalışan iki iş
! Sonuçları birbirine bağımlı
! Sonuç başarılı ya da başarısız tek bir yerde
toplanmalı

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RxJava Birleştirme
operatörleri

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private fun readFileSingle(name: String): Single {
return Single.create { singleEmitter ->
singleEmitter.onSuccess(readFile(name))
}

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Single.zip(readFileSingle("thefile.txt")),
readFileSingle(“theotherfile.txt")),
BiFunction { t1, t2 ->
"$t1 \n$t2"
}).observeOn(AndroidSchedulers.mainThread())
.subscribe({
textView.text = it
}, { e ->
}
Log.e(TAG,e.message,e)
})

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readFileSingle("theotherfile.txt")),
"$t1 \n$t2"
.subscribe({
textView.text = it
}, { e ->
}
})

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"$t1 \n$t2"
.subscribe({
textView.text = it
}, { e ->
}
})

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"$t1 \n$t2"
.subscribe({
textView.text = it
}, { e ->
}
})

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"$t1 \n$t2"
.subscribe({
textView.text = it
}, { e ->
}
})

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coroutineScope

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private fun readFileDeferred(name: String) = async(Dispatchers.IO) {
readFile(name)
}

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launch(Dispatchers.Main) {
try {
coroutineScope {
val s1 = readFileDeferred("thefile.txt").await()
val s2 = readFileDeferred("theotherfile.txt").await()
textView.text = "$s1 \n$s2"
}
}
}

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try {
coroutineScope {
}
}
}

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try {
coroutineScope {
}
}
}

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Senaryo #3 Asenkron bir api’yi kullanma
! Callback ile çalışan bir api’ı belirli bir flowun içerisine
katmak istiyoruz
! Elimizde halihazırda bir sonuç varsa sonucu dönüp
sonuç yoksa apiden gelecek sonucu döndürmek
istiyoruz.
! Kodlama stilinin proje geneli ile aynı olmasını istiyoruz.

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RxJava ile asenkron
api

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private fun getAppFolder(): Single {
return Single.create { emitter ->
if (folder != null) {
emitter.onSuccess(folder !!)
} else {
getDriveResourceClient().appFolder
.addOnSuccessListener { appFolder ->
folder = appFolder
emitter.onSuccess(appFolder)
}.addOnFailureListener {
emitter.onError(it)
}
}
}
}

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