我很难理解如何迁移到谷歌认可的Android现代开发。在MVVM中，“业务逻辑”应该在ViewModel中，建议ViewModel的子类应该是Context不知道的，但大多数Android类需要Context才能提供任何功能。例如，如果没有Context（如WifiManager和ConnectivityManager），则无法获取对系统服务的引用。
举个例子，我试图为一个应用构建一个简单的架构，它只有一个按钮，可以根据ConnectivityManager文档中概述的活动默认网络链接来更改其图像。这个系统级操作应该在代码的“业务逻辑”区域处理，因为它与UI无关。它检测网络状态，改变了ViewModel中的一些状态数据，这应该是神奇的。由于一些Observable通知UI数据已更改并触发ComposeRecomposition更改按钮图像，因此更改按钮图像。我已经开始构建此应用程序，我将发布到目前为止我所拥有的内容。如果ViewModel是应用程序状态的仲裁者，那么创建一个没有上下文的ViewModel？这似乎是自相矛盾的。
ViewModel摘录：

enum class ConnectivityState {
    WIFI,
    CELLULAR,
    DISCONNECTED
}

class MainActivityViewModel(context: Context) : ViewModel() {
    private val logger: Logger = LoggerFactory.getLogger(this::class.java)

    private val _uiState = MutableStateFlow(MainUIState())
    val uiState: StateFlow<MainUIState> = _uiState.asStateFlow()

    //TODO: how to perform system level business logic in ViewModel without Context reference?
    //DESIRED: keep this 'business logic' away from UI.  ViewModel should be appropriate but Context should not be used here?
    private val wifiManager =
        context.getSystemService(WIFI_SERVICE) as WifiManager
    private val connectivityManager =
        context.getSystemService(CONNECTIVITY_SERVICE) as ConnectivityManager

    /**
     * a NetworkCallback which will be triggered when a change in network state is sent from the system
     */
    private val networkCallback = object : ConnectivityManager.NetworkCallback() {
        override fun onAvailable(network: Network) {
            super.onAvailable(network)
            _uiState.value.connectivityState = getConnectivityState()
        }

        override fun onCapabilitiesChanged(
            network: Network,
            networkCapabilities: NetworkCapabilities
        ) {
            super.onCapabilitiesChanged(network, networkCapabilities)
            _uiState.value.connectivityState = getConnectivityState()
        }

        override fun onLost(network: Network) {
            super.onLost(network)
            _uiState.value.connectivityState = getConnectivityState()
        }
    }

    init {
        connectivityManager.registerDefaultNetworkCallback(networkCallback)
        _uiState.value.connectivityState = getConnectivityState()
    }

    fun getConnectivityState(): ConnectivityState {
        //these objects represent information about the currently active network
        val currentNetwork = connectivityManager.getActiveNetwork()
        val capabilities = connectivityManager.getNetworkCapabilities(currentNetwork)
        val linkProperties = connectivityManager.getLinkProperties(currentNetwork)

        if(currentNetwork == null) {
            return ConnectivityState.DISCONNECTED
        }

        if(wifiManager.isWifiEnabled) {
            //if wifi is enabled, it should be the current active network
            val isWifi = capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)
            if(isWifi != null) {
                if(isWifi) {
                    //the current active link is a WiFi connection
                    logger.debug("Current active default network is WiFi.")
                    return ConnectivityState.WIFI
                }
            }
        }

        val isCellular = capabilities?.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)
        if(isCellular != null) {
            if(isCellular) {
                logger.info("Current active default network is cellular data.")
                return ConnectivityState.CELLULAR
            }
        }

        return ConnectivityState.DISCONNECTED
    }
}

data class MainUIState(
    var connectivityState: ConnectivityState = ConnectivityState.DISCONNECTED
)

字符串
活动摘录：

@Composable
    fun wifiComposable() {
        //WiFi button
        Button(
            onClick = {
                MainActivity.openWifiSettings(LocalContext.current)
            }
        ) {
            //TODO: this image changes between DOWN, CELLULAR, WIFI images depending on connectivity state / source
            Image(
                //TODO: 'StateFlow.value should not be called within composition' why?
                //DESIRED BEHAVIOR: when this state value changes, recomp and change image accordingly
                painter = when(viewModel.uiState.value.connectivityState) {
                    ConnectivityState.WIFI -> painterResource(id = R.drawable.wifi_indicator)
                    ConnectivityState.CELLULAR -> painterResource(id = R.drawable.cellular_indicator)
                    ConnectivityState.DISCONNECTED -> painterResource(id = R.drawable.down_indicator)
                },
                modifier = Modifier.size(40.dp),
                contentDescription = "WiFi Settings")
        }
    }

型