I have a collection of `Node`s which all have a `StateFlow<NodeState>` property. I also have a...

# coroutines

[William Reed]

I have a collection of `Node`s which all have a StateFlow<NodeState> property. I also have a NodeManager which in turn has a MutableList<Node> (which is just exposed as a List<Node>. At my UI level I want to display something based on each `Node`’s state.

it starts to get a little weird since I need to observe each nodes state flow as well as account for the `NodeManager`s collection of nodes possibly changing. Any suggestions for how to approach this such that in my UI level I can end up with a List<NodeState> so I can render views from it?

I’ve tried exposing a StateFlow<List<Node>> from the NodeManager but then from the UI level I would need to somehow manage the collection of each node / the node’s possibly getting removed or added

[Nick Allen]

If you want to listen for changes to state it must be observable so it can't just be a List.

What about something along the lines of:

class Node {
    val state = MutableStateFlow<Int>(0)
}

class NodeManagerNeedsBetterName {
    val nodes = MutableStateFlow<List<Node>>(emptyList())
    val nodeStates = nodes.flatMapLatest { nodeList ->
        combine(nodeList.map { it.state }) { it.toList() }
    }
}

[William Reed]

sure i was just hand waving the List part (and I already have other names for node/ node manager just simplifying here). Let me think about that snippet you sent though