Hi, Why on MutableLiveData value change Compose didn`t compose the UI?

# compose

[Asad Mukhtar]

Hi, Why on MutableLiveData value change Compose didn`t compose the UI?

[Asad Mukhtar]

viewModel.listOfRoundFlights.observeAsState()
    .value?.let{
 // some compose function
}

[Adam Powell]

If you're modifying a list and setting the livedata to that same list again, compose doesn't consider that a new value so it won't recompose. Emit a new list instead of mutating the contents of the livedata

[Adam Powell]

Alternatively, skip the livedata entirely and use mutableStateListOf for your listOfRoundFlights in your ViewModel and you can modify the list directly and compose will notice and respond to the modifications

[Asad Mukhtar]

@Adam Powell i use this

private val _listOfRoundFlights =
    MutableStateFlow<List<Pair<Pair<Int, Int>, Pair<OutboundX, OutboundX>>>>(listOf())

val listOfRoundFlights: StateFlow<List<Pair<Pair<Int, Int>, Pair<OutboundX, OutboundX>>>> =
    _listOfRoundFlights

But same problem again.

[Adam Powell]

I think you should consider writing one or more data classes; Pair<Pair<Int, Int>, Pair<OutboundX, OutboundX>> is quite hard to read or make sense of 🙂

[Adam Powell]

if at any point in your other code you are modifying a mutable list and expecting it to emit a new value, compose's state management does not consider it a new value since it is the same list object. This is the same regardless of whether you're importing that state from a livedata or a flow

[Chris Fillmore]

_listOfRoundFlights.update {
  it.toMutableList().apply {
    // modify your list here
  }
}

Something like the above should do