android - 如何更改 kotlin StateFlow 的数据源

Question

我正在将此代码示例迁移到 StateFlow。

class RosterMotor(private val repo: ToDoRepository) : ViewModel() {
  private val _states = MediatorLiveData<RosterViewState>()
  val states: LiveData<RosterViewState> = _states
  private var lastSource: LiveData<RosterViewState>? = null

  init {
    load(FilterMode.ALL)
  }

  fun load(filterMode: FilterMode) {
    lastSource?.let { _states.removeSource(it) }

    val items =
      repo.items(filterMode).map { RosterViewState(it, filterMode) }.asLiveData()

    _states.addSource(items) { viewstate ->
      _states.value = viewstate
    }

    lastSource = items
  }
...
}

此示例取自https://commonsware.com/AndExplore/ book

我可以想到这个解决方案，但我不确定这是否是最好的方法

private val _states = MutableStateFlow(RosterViewState())
val states: StateFlow<RosterViewState> = _states

init {
    load(ALL)
}

fun load(filterMode: FilterMode) {
    viewModelScope.launch {
        repository.items(filterMode).map { RosterViewState(it, filterMode) }
            .collect {
                _states.value = it
            }
    }
}

那么我们如何使用 StateFlow 来实现这个场景。

标签： androidkotlin-stateflow