Espresso 不会等到 RecyclerView 从 LiveData 获取更新

Question

StatsFragment 包含 recyclerview。 recylcerView 显示“Stat”。 recylcerView 适配器通过观察 ViewModel 中的 LiveData 来更新。 ViewModel 通过 Flow 从存储库获取更新。在 StatsFragment 中是一个 FAB，它打开一个 DialogFragment，可以添加一个新的 Stat。

我怀疑问题是 espresso 没有等到适配器更新并且新数据显示在屏幕上。

如何让 espresso 等到存储库流发出它的值，将其传递给 viewModels LiveData，以便更新片段中的列表以通知适配器在 recyclerview 中显示列表？

StatsFragment

class StatsFragment : Fragment() {

    private lateinit var binding: FragmentStatsBinding
    private val mainViewModel: MainViewModel by viewModel()

    private lateinit var recyclerView: RecyclerView
    private lateinit var statsAdapter: StatsAdapter
    private lateinit var layoutManager: LinearLayoutManager

    private lateinit var addStats: FloatingActionButton

    private lateinit var addStatFragment: DialogFragment

    private val stats = mutableListOf<Stat>()

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        binding = FragmentStatsBinding.inflate(inflater, container, false)
        binding.lifecycleOwner = viewLifecycleOwner
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        initObserver()
        initUi()
    }

    private fun initObserver() {
        mainViewModel.stats.observe(viewLifecycleOwner, Observer { statList ->
            stats.clear()
            stats.addAll(statList)
            statsAdapter.notifyDataSetChanged()
        })
    }

    private fun initUi() {
        statsAdapter = StatsAdapter(stats)
        layoutManager = LinearLayoutManager(requireContext())
        recyclerView = binding.recyclerViewStatsData
        recyclerView.layoutManager = layoutManager
        recyclerView.adapter = statsAdapter

        addStats = binding.fabStatsAddStat
        addStats.setOnClickListener(addStatOnClickListener)
    }

    private val addStatOnClickListener = View.OnClickListener {
        addStatFragment = AddStatFragment()
        addStatFragment.show(requireActivity().supportFragmentManager, "addStatFragment")
    }

}

AddStatFragment

class AddStatFragment : DialogFragment() {

    private lateinit var binding: FragmentInputBinding
    private val mainViewModel: MainViewModel by viewModel()

    private lateinit var date: TextView
    private lateinit var time: TextView

    private lateinit var confirm: Button

    override fun onStart() {
        super.onStart()
        val width = resources.displayMetrics.widthPixels
        val height = resources.displayMetrics.heightPixels
        dialog!!.window?.setLayout(width, WRAP_CONTENT)
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        binding = FragmentInputBinding.inflate(inflater, container, false)
        binding.viewModel = mainViewModel
        binding.lifecycleOwner = viewLifecycleOwner
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        initUi()
    }

    private fun initUi() {
        date = binding.textViewInputDate
        time = binding.textViewInputTime
        confirm = binding.buttonInputConfirm

        confirm.setOnClickListener {
            mainViewModel.insertStat()
            dialog!!.hide()
        }
    }
}

MainViewModel

class MainViewModel(private val repository: Repository, application: Application) :
    AndroidViewModel(application) {

    private val _stats = repository.getAllStats().asLiveData()
    val stats: LiveData<List<Stat>>
        get() = _stats

    private val _insertStatStatus = MutableLiveData<Event<Resource<Stat>>>()
    val insertStatStatus: LiveData<Event<Resource<Stat>>>
        get() = _insertStatStatus

    val weight = MutableLiveData<String>()
    val waist = MutableLiveData<String>()
    val kCal = MutableLiveData<String>()
    val date = MutableLiveData<String>()
    val time = MutableLiveData<String>()

    private fun insertStatIntoDatabase(stat: Stat) {
        viewModelScope.launch {
            repository.insertStat(stat)
        }
    }

    internal fun insertStat(weight: String, waist: String, kCal: String, date: String, time: String) {
        val newStat = Stat(weight.toDouble(), waist.toDouble(), kCal.toDouble(), date, time)
        insertStatIntoDatabase(newStat)
        _insertStatStatus.value = Event(Resource.success(newStat))
    }


    internal fun insertStat() {
        insertStat(weight.value ?: "", waist.value ?: "", kCal.value ?: "", date.value ?: "", time.value ?: "")
    }
}

FakeRepository

class FakeStatsRepositoryAndroidTest: Repository {

    private val fakeStats = MutableLiveData<MutableList<Stat>>()
    private val underlyingList = mutableListOf<Stat>()
    private var idCounter = 1

    init {
        fakeStats.value = underlyingList
    }

    override fun getAllStats(): Flow<List<Stat>> {
        return fakeStats.asFlow()
    }

    override suspend fun insertStat(stat: Stat) {

        val newStat = Stat(stat.weight,stat.waist,stat.kCal,stat.date,stat.time,idCounter)
        idCounter++
        underlyingList.add(newStat)
    }

    override suspend fun deleteStat(stat: Stat) {
        underlyingList.remove(stat)
    }

    override suspend fun updateStat(stat: Stat) {
        if(underlyingList.removeIf { it.id == stat.id }) {
            underlyingList.add(stat)
        } else {
            return
        }
    }
}

测试

    @Test
    fun openingAddStatFragmentWhenEnteringInformationAndPressingConfirmThenStatIsVisibleInList() {
        val statToAdd = Stat(70.1,88.5,2300.0,"today", "now",id = 1)

        onView(withId(R.id.fab_stats_addStat)).perform(click())
        onView(withId(R.id.textInputEditText_input_weight)).perform(typeText(statToAdd.weight.toString()))
        onView(withId(R.id.textInputEditText_input_waist)).perform(typeText(statToAdd.weight.toString()))
        onView(withId(R.id.textInputEditText_input_kcal)).perform(typeText(statToAdd.weight.toString()))
        onView(withId(R.id.button_input_confirm)).perform(click())
        onView(withId(R.id.recyclerView_stats_data)).perform(RecyclerViewActions.scrollTo<StatsViewHolder>(hasDescendant(withText("70.1"))))
    }

我删除了一些代码（输入值检查、时间和日期相关的东西等）

Answer 1

错误在别处。没有来自 Fake 存储库的任何数据，因此 liveData 没有更新。

Espresso 不会等到 RecyclerView 从 LiveData 获取更新

Espresso doesn't wait till RecyclerView gets update from LiveData

android

viewmodel

android-espresso

android-recyclerview