Hey guys, I am using

MutableStateFlow

in my project. When we initialise the

MutableStateFlow

object we need to give default value.

val topics = MutableStateFlow<List<String>>(emptyList())

when I collect this value

[null, "Hello", "world"]

I want to pass this list in

adapter

. So is there a way we can remove the null object before passing in adapter or Is there any better way ?

viewModel.topics.collect { topicsList ->
    println(topicsList)         // [null, "Hello", "world"]
    adapter.submitList(topicsList)
}

is this what you want?

adapter.submitList(topicsList.filterNotNull())

Yes but if I add this line is do again check in whole list ?

I think you always need to filter those null value manually because it came from the data source (I suppose?). Also if you concern with the performance, perhaps you can move the filter computation to other dispatcher first. Something like this:

viewModel.topics
    .filter { ... }
    .flowOn(Dispatcher.Default)
    .collect { ... }

Okk great. Thanka

I would be interested in how this turns out. My guess is that adding flowOn() actually takes longer (in terms of CPU time used on main thread) due to the overhead of having to dispatch in and out of another thread each time vs simply comparing for nulls It would depend on how big topicList is. My 'guess' is that it would take a list > several 1000's long before it was less time (cpu time used in main thread) to switch threads and back vs filtering inline .