For callbackFlow: You cannot use emit() as the simple Flow (because it’s a suspend function) inside a callback. Therefore the callbackFlow offers you a synchronized way to do it with the trySend() option. Example: fun observeData() = flow { myAwesomeInterface.addListener{ result -> emit(result) // NOT ALLOWED } } So, coroutines offer you the option of … Read more
You can use StateFlow or SharedFlow APIs for such use case. Here’s a sample code with the usage of StateFlow. import kotlinx.coroutines.* import kotlinx.coroutines.flow.* val chatFlow = MutableStateFlow<String>(“”) fun main() = runBlocking { // Observe values val job = launch { chatFlow.collect { print(“$it “) } } // Change values arrayOf(“Hey”, “Hi”, “Hello”).forEach { delay(100) … Read more
Collect will collect every value , and CollectLatest will stop current work to collect latest value, The crucial difference from collect is that when the original flow emits a new value then the action block for the previous value is cancelled. flow { emit(1) delay(50) emit(2) }.collect { value -> println(“Collecting $value”) delay(100) // Emulate … Read more
It seems that the Android team changed the API and documentation after this thread. You can check it here: Continuous collection SharedFlow/StateFlow is a hot flow, and, as described in the docs, A shared flow is called hot because its active instance exists independently of the presence of collectors. It means the scope that launches … Read more
Probably, you are using the direct collect() function on Flow. For your syntax, you need to import the collect() extension function. (and I really wish that they did not name these the same…)
The answer is, NO, collect is not only internal kotlinx.coroutines API. The error message is misleading. As per @ir42’s comment, add import kotlinx.coroutines.flow.collect solve the problem. Additional info, why I didn’t pick collectLatest as the answer collect and collectLatest is different. Using this example fun simple(): Flow<Int> = flow { // flow builder for (i … Read more
I can observe LiveData from multiple Fragments. Can I do this with Flow? If yes then how? Yes. You can do this with emit and collect. Think emit is similar to live data postValue and collect is similar to observe. Lets give an example. Repository // I just faked the weather forecast val weatherForecast = … Read more