For example, we can create a LiveData object using a liveData builder function:
var liveData: LiveData<String> = liveData(Dispatchers.IO) {
delay(1000)
emit ("hello")
delay(1000)
emit ("world")
}
This is useful in ViewModel, I create a LiveData object that receives multiple data values from an asynchronous heavy function in one line.
But what if I already have a MutableLiveData object and just want to post values there, without creating a new LiveData object? How can I do this?
I need a way to asynchronously emit multiple values into existed MutableLiveData object inside a ViewModel scope to automatically finish all running tasks when the ViewModel will be cleared.
You can post to a MutableLiveData in a coroutine launched from viewModelScope.
private val myMutableLiveData = MutableLiveData<String>()
fun someFun() {
viewModelScope.launch {
myMutableLiveData.value = “Hello”
delay(500L)
myMutableLiveData.value = “World”
myMutableLiveData.value = someSuspendFunctionRetriever()
val result = withContext(Dispatchers.IO) {
someBlockingCallRetriever()
}
myMutableLiveData.value = result
// or use post() when not on Main dispatcher:
withContext(Dispatchers.IO) {
val result = someBlockingCallRetriever()
myMutableLiveData.post(result)
}
}
}