kotlin-coroutines

问题 I'm really struggling with this & would appreciate some help please. I'm learning Android Kotlin & building an app that displays a list of walking routes (downloaded from the cloud) in a RecyclerView &, when a route is selected I want to display all details of the route - a simple Master-Detail app. Since, I'm learning I also want to try and use best practice. I have most of it working fine using a Room database & a Repository. The database is correctly populated and the RecyclerView displays

问题 When using Firebase Cloud Messaging on Android, it is often desirable to notify the current Activity of an incoming push notification. One of the recommended ways to do this has been to use LocalBroadcastManager to send an Intent from the FirebaseMessagingService implementation to the Activity (StackOverflow example answer). However, as of version 1.1.0-alpha01 (2018-12-17), LocalBroadcastManager is deprecated: LocalBroadcastManager is an application-wide event bus and embraces layer

问题 I read all the kotlinx UI docs and implement a ScopedActivity like described there (see the code below). In my ScopedActivity implementation, I also add a CouroutineExceptionHandler and despite that I pass my exception handler to all my coroutines, my users are experiencing crashes and the only info I get in the stacktrace is "Job was cancelled". I searched for a couple of days now but I did not find a solution and my users are still randomly crashing but I do not understand why... Here is my

问题 I've one LiveData named sortOrder and then I've another variable named myData that observes any change to sortOrder and populates data accordingly. class TestViewModel @ViewModelInject constructor() : ViewModel() { private val sortOrder = MutableLiveData<String>() val myData = sortOrder.map { Timber.d("Sort order changed to $it") "Sort order is $it" } init { sortOrder.value = "year" } } Observing in Activity class TestActivity : AppCompatActivity() { private val viewModel: TestViewModel by

问题 I've one LiveData named sortOrder and then I've another variable named myData that observes any change to sortOrder and populates data accordingly. class TestViewModel @ViewModelInject constructor() : ViewModel() { private val sortOrder = MutableLiveData<String>() val myData = sortOrder.map { Timber.d("Sort order changed to $it") "Sort order is $it" } init { sortOrder.value = "year" } } Observing in Activity class TestActivity : AppCompatActivity() { private val viewModel: TestViewModel by

问题 I'm trying to build a native in Windows. I'm not sure where to put the dependency for implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.5'. My current gradle file looks like this: buildscript { ext.kotlin_version = '1.3.72' repositories { mavenCentral() } dependencies { classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion") } } plugins { id 'org.jetbrains.kotlin.multiplatform' version '1.3.72' } dependencies { implementation 'org.jetbrains.kotlinx:kotlinx

问题 Let's assume I'm writing a library that returns a string which is a complex and long running task. I can chose between offering this interface StringGenerator { suspend fun generateString(): String } or interface StringGenerator { fun generateString(): Deferred<String> } Are there any (dis-)advantages of either of the options and which are they? Which should I choose? 回答1: Kotlin coroutines are designed along the "sequential by default" guideline. That means that your API should always expose

问题 I have created a very simplified version of my issue below. The strict mode is set up with the following policies: StrictMode.setThreadPolicy( StrictMode.ThreadPolicy.Builder() .detectDiskReads() .detectDiskWrites() .detectNetwork() // or .detectAll() for all detectable problems .penaltyLog() .penaltyDeath() .build() ) The view model has only one function which crashes the application when invoked. The function does nothing (it has an empty body) class MyViewModel : ViewModel() { fun foo() {

问题 I have created a very simplified version of my issue below. The strict mode is set up with the following policies: StrictMode.setThreadPolicy( StrictMode.ThreadPolicy.Builder() .detectDiskReads() .detectDiskWrites() .detectNetwork() // or .detectAll() for all detectable problems .penaltyLog() .penaltyDeath() .build() ) The view model has only one function which crashes the application when invoked. The function does nothing (it has an empty body) class MyViewModel : ViewModel() { fun foo() {

问题 I used to use Channel to send out click event from Anko View class to Activity class, however more and more Channel functions are marked as deprecated. So I wanted to start using Flow apis. I migrated code below: private val btnProduceChannel = Channel<Unit>() val btnChannel : ReceiveChannel<Unit> = btnProduceChannel // Anko button { onClick { btnProduceChannel.send(Unit) } } to: lateinit var btnFlow: Flow<Unit> private set button { btnFlow = flow { onClick { emit(Unit) } } } I have to mark