android - Kotlin接口(interface)无法实例化!接口(interface)名称 : kotlinx. 协程.Deferred

Question

我正在开发一个 Android 应用程序，该应用程序将 MVVM 与 Koin 和 Retrofit 结合使用。

突然间我不断收到错误消息

Interface can't be instantiated! Interface name: kotlinx.coroutines.Deferred

但是我找不到问题出在哪里。

当前的结构是这样的。

View 模型。

class ExchangeRateBanksViewModel (private val comercialBanksRepository: ComercialBanksRepository): ViewModel() , KoinComponent{

    private val _uiState = MutableLiveData<CredentialsDataState>()
    val uiState: LiveData<CredentialsDataState> get() = _uiState

    init {
        viewModelScope.launch {
            runCatching {
                emitUiState(showProgress = true)
                comercialBanksRepository.getExchangeRateByToday()
            }.onSuccess {root ->
                val nameMap: MutableList<ExchangeRate> = root.data.map { it }.toMutableList()
                emitUiState(result = Event(nameMap))
            }.onFailure {
                println(it.printStackTrace())
            }
        }
    }

    private fun emitUiState(showProgress: Boolean = false, result: Event<List<ExchangeRate>>? = null, error: Event<Int>? = null){
        val dataState = CredentialsDataState(showProgress, result, error)
        _uiState.value = dataState
    }

    data class CredentialsDataState(val showProgress: Boolean, val result: Event<List<ExchangeRate>>?, val error: Event<Int>?)
}

界面

interface ComercialBanksInterface {
    @GET("api/commercialBankExchangeRates/date/today")
    suspend fun requestExchangeRateToday(): Deferred<RootExchangeRate>
}

存储库。

interface ComercialBanksRepository {
    suspend fun getExchangeRateByToday(): RootExchangeRate
}

class ComercialBanksRepositoryImplement(val comercialBanksService: ComercialBanksInterface): ComercialBanksRepository{
    override suspend fun getExchangeRateByToday(): RootExchangeRate {
        return comercialBanksService.requestExchangeRateToday().await()
    }
}

最后是我调用 viewModel 的部分。

exchangeRateBanksViewModel.uiState.observe(this, Observer {
            val dataState = it ?: return@Observer
            if (!dataState.showProgress) displayHideSkeleton(hide = true) else displayHideSkeleton(hide = false)
            if (dataState.result != null && !dataState.result.consumed){
                dataState.result.consume()?.let { result ->
                    println("RESULT: ${result}")
                    exchangeRateAdapter.submitList(result)
                }
            }
            if (dataState.error != null && !dataState.error.consumed){
                dataState.error.consume()?.let { error ->
                    Toast.makeText(applicationContext, resources.getString(error), Toast.LENGTH_LONG).show()
                }
            }
        })

我找不到界面的哪个部分有问题...

Answer 1

Retrofit 已处理挂起函数，因此您无需返回 Deferred。只需返回 RootExchangeRate 即可。

此外，您的存储库的功能也应该是可挂起的，并且 View 模型应该返回一个 LiveData，其中 Activity (或 fragment )将观察它。