Coroutines not working in jetpack Compose - kotlin

Question

I use the following way to get network data.
I start a network request in a coroutine but it doesn't work, the pagination load is not called.
But if I call the network request through the init method in the ViewModel I can get the data successfully.
#Composable
fun HomeView() {
val viewModel = hiltViewModel<CountryViewModel>()
LaunchedEffect(true) {
viewModel.getCountryList() // Not working
}
val pagingItems = viewModel.countryGroupList.collectAsLazyPagingItems()
Scaffold {
LazyColumn(
contentPadding = PaddingValues(horizontal = 16.dp, vertical = 96.dp),
verticalArrangement = Arrangement.spacedBy(32.dp),
modifier = Modifier.fillMaxSize()) {
items(pagingItems) { countryGroup ->
if (countryGroup == null) return#items
Text(text = "Hello", modifier = Modifier.height(100.dp))
}
}
}
}
#HiltViewModel
class CountryViewModel #Inject constructor() : ViewModel() {
var countryGroupList = flowOf<PagingData<CountryGroup>>()
private val config = PagingConfig(pageSize = 26, prefetchDistance = 1, initialLoadSize = 26)
init {
getCountryList() // can work
}
fun getCountryList() {
countryGroupList = Pager(config) {
CountrySource()
}.flow.cachedIn(viewModelScope)
}
}
I don't understand what's the difference between the two calls, why doesn't it work?
Any helpful comments and answers are greatly appreciated.

Answer 1

I solved the problem, the coroutine was used twice in the code above, which caused network data to not be fetched.
A coroutine is used here：
fun getCountryList() {
countryGroupList = Pager(config) {
CountrySource()
}.flow.cachedIn(viewModelScope)
}
Here is another coroutine：
LaunchedEffect(true) {
viewModel.getCountryList() // Not working
}
current usage：
val execute = rememberSaveable { mutableStateOf(true) }
if (execute.value) {
viewModel.getCountryList()
execute.value = false
}