ScopedViewModel

ScopedViewModel.kt

open class ScopedViewModel : ViewModel() {
    private val job = Job()
    protected val scope: CoroutineScope = job + Dispatchers.Main

    override fun onCleared() {
        super.onCleared()
        job.cancel()
    }
}

zDetailViewModel.kt

class DetailViewModel : ScopedViewModel() {
  
    fun startTask() {
        scope.launch {
            // Switch the 'background' thread 
            withContext(Dispatchers.Default) {
                // do your long-running thing
            }
            // We're now back on the Android's Main thread (since we're using
            // the ScopedViewModel's scope)
            updateUi()
        }
    }
    
}

launch // no launch(ui){...} ?

@XinyueZ UI is deprecated in favour of Dispatchers.Main. And since he set that as the coroutine context for theViewModel, launch uses that by default.

That being said, I prefer the default dispatcher to be Dispatchers.Default and switch to the main (or IO, but this shouldn't be necessary with the experimental scheduler) context when necessary.

I C, got it, I have converted my project from experimental to non-experimental and I have seen a lot different things.

I prefer

    override val coroutineContext: CoroutineContext
        get() = Dispatchers.Main + job

private val scope: CoroutineScope = job + Dispatchers.Main
doesn't compile... it expect a CoroutineScope

Yes, it doesn't compile, I have solved it like this:
protected val scope: CoroutineScope = CoroutineScope(Dispatchers.Main + job)

Great stuff!
Is it ok implement CoroutineScope from viewModel and just use launch instead of scope.launch?