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March 27, 2019 17:15
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LiveData implementation that is based on Kotlin coroutines
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class MainViewModel : DisposableViewModel() { | |
val title = ChannelLiveData("New Title 0") | |
val isReady = ChannelLiveData(false) | |
init { | |
disposableLaunch { | |
(1..Int.MAX_VALUE).forEach { time -> | |
delay(1, TimeUnit.SECONDS) | |
title.send("New Title $time") | |
} | |
} | |
disposableLaunch { | |
title | |
.openSubscription() | |
.map { it.contains("3") } | |
.consumeEach { isReady.send(it) } | |
} | |
} | |
} | |
open class DisposableViewModel : ViewModel() { | |
protected val compositeDisposable = mutableListOf<Job>() | |
override fun onCleared() { | |
super.onCleared() | |
runBlocking { compositeDisposable.forEach { it.cancelAndJoin() } } | |
} | |
protected fun disposableLaunch(block: suspend CoroutineScope.() -> Unit) { | |
compositeDisposable += launch(block = block) | |
} | |
} | |
class ChannelLiveData<T>(value: T) : LiveData<T>(), BroadcastChannel<T> { | |
private val channel = ConflatedBroadcastChannel(value) | |
private var subscription: Closeable? = null | |
override fun onActive() { | |
super.onActive() | |
subscription = channel.openSubscription().apply { | |
launch(CommonPool) { consumeEach(::postValue) } | |
} | |
} | |
override fun onInactive() { | |
super.onInactive() | |
subscription?.close() | |
} | |
override val isClosedForSend: Boolean | |
get() = channel.isClosedForSend | |
override val isFull: Boolean | |
get() = channel.isFull | |
override val onSend: SelectClause2<T, SendChannel<T>> | |
get() = channel.onSend | |
override fun close(cause: Throwable?) = channel.close() | |
override fun offer(element: T) = channel.offer(element) | |
override fun openSubscription() = channel.openSubscription() | |
override suspend fun send(element: T) = channel.send(element) | |
} |
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