Will collection data from Flow in viewModelScope maybe block UI in Android Studio?

The Code A is from official article about Flow

viewModelScope.launch{} run in UI thread by default, I think suspend fun fetchLatestNews() will run in UI thread by default too, so I think Code A maybe cause UI blocked when fetchLatestNews() is long time operation, right?

I think Code B can fix the problem, right?

Code A

class LatestNewsViewModel(
    private val newsRepository: NewsRepository
) : ViewModel() {

    init {
        viewModelScope.launch {
            // Trigger the flow and consume its elements using collect
            newsRepository.favoriteLatestNews.collect { favoriteNews ->
                // Update View with the latest favorite news
            }
        }
    }
}



class NewsRemoteDataSource(
    private val newsApi: NewsApi,
    private val refreshIntervalMs: Long = 5000
) {
    val latestNews: Flow<List<ArticleHeadline>> = flow {
        while(true) {
            val latestNews = newsApi.fetchLatestNews()
            emit(latestNews) // Emits the result of the request to the flow
            delay(refreshIntervalMs) // Suspends the coroutine for some time
        }
    }
}

// Interface that provides a way to make network requests with suspend functions
interface NewsApi {
    suspend fun fetchLatestNews(): List<ArticleHeadline>
}

Code B

class LatestNewsViewModel(
    private val newsRepository: NewsRepository
) : ViewModel() {

    init {
        viewModelScope.launch(Dispatchers.IO) {
           //The same
        }
    }
}


//The same

Added content:

To Tenfour04: Thanks!

I think a suspend function maybe block UI, so I think to define dispatchers is the most important in order not to block UI! Is it right?

Code 1 work well when I click "Start" button to display the information if I use Dispatchers.IO.

Code 2 is freezed and no information updated when I click "Start" button if I use Dispatchers.Main.

Code 3 can work just like Code 1 if I use Dispatchers.Main, the reason is only because I set delay(100).

BTW, Flow is suspend. So if there is a long time operation even if it's wrapped with coroutine instead of soundDbFlow().collect { myInfo.value = it.toString() }, I think I can get the same test result just like Code 1, Code 2 and Code 3.

And more, Code 4 is OK after I added flowOn(Dispatchers.IO) for the Flow even if it is launched in viewModelScope.launch(Dispatchers.Main){} !

Code 1 OK

class HandleMeter: ViewModel() {
    var myInfo = mutableStateOf("World")
    private var myJob: Job?=null
    private var k=0

    private fun soundDbFlow() = flow {
          while (true) {
             emit(k++)
             delay(0)
          }
   }

    fun calCurrentAsynNew() {
        myJob?.cancel()
        myJob = viewModelScope.launch(Dispatchers.IO){
            soundDbFlow().collect { myInfo.value = it.toString() }
        }
    }

    fun cancelJob(){
        myJob?.cancel()
    }

}


@Composable
fun Greeting(handleMeter: HandleMeter) {
    var info = handleMeter.myInfo
    Column(
        modifier = Modifier.fillMaxSize()
    ) {
        Text(text = "Hello ${info.value}")

        Button(
            onClick = { handleMeter.calCurrentAsynNew() }
        ) {
            Text("Start")
        }

        Button(
            onClick = { handleMeter.cancelJob() }
        ) {
            Text("Stop")
        }
    }
}

Code 2 Freezed

class HandleMeter: ViewModel() {
   private fun soundDbFlow() = flow {
          while (true) {
             emit(k++)
             delay(0)
          }
   }

    fun calCurrentAsynNew() {
        myJob?.cancel()
        myJob = viewModelScope.launch(Dispatchers.Main){
            soundDbFlow().collect { myInfo.value = it.toString() }
        }
    }
    ...
   //The same

}
...
//The same

Code 3 OK

class HandleMeter: ViewModel() {
   private fun soundDbFlow() = flow {
          while (true) {
             emit(k++)
             delay(100)  //It's 100
          }
   }

    fun calCurrentAsynNew() {
        myJob?.cancel()
        myJob = viewModelScope.launch(Dispatchers.Main){
            soundDbFlow().collect { myInfo.value = it.toString() }
        }
    }
    ...
    //The same

}
...
//The same

Code 4 Ok

class HandleMeter: ViewModel() {
   private fun soundDbFlow() = flow {
        while (true) {
            emit(k++)
            delay(0)
        }
    }.flowOn(Dispatchers.IO)// I added

    fun calCurrentAsynNew() {
        myJob?.cancel()
        myJob = viewModelScope.launch(Dispatchers.Main){
            soundDbFlow().collect { myInfo.value = it.toString() }
        }
    }

    ...
    //The same

}
...
//The same