Monitor network connectivity in android using callbackFlow.

NetworkMonitor.kt

interface NetworkMonitor {
    val isOnline: Flow<Boolean>
}

class NetworkMonitorImpl @Inject constructor(
    @ApplicationContext private val context: Context,
    @Dispatcher(IO) private val ioDispatcher: CoroutineDispatcher,
) : NetworkMonitor {
    override val isOnline: Flow<Boolean>
        get() = callbackFlow {
            val connectivityManager = context.getSystemService<ConnectivityManager>()
            if (connectivityManager == null) {
                channel.trySend(false)
                channel.close()
                return@callbackFlow
            }

            val callback = object : NetworkCallback() {
                private val networks = mutableSetOf<Network>()

                override fun onAvailable(network: Network) {
                    networks += network
                    channel.trySend(true)
                }

                override fun onLost(network: Network) {
                    networks -= network
                    channel.trySend(networks.isNotEmpty())
                }
            }

            val request = Builder()
                .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
                .build()
            connectivityManager.registerNetworkCallback(request, callback)

            channel.trySend(connectivityManager.isCurrentlyConnected())

            awaitClose {
                connectivityManager.unregisterNetworkCallback(callback)
            }
        }.flowOn(ioDispatcher).conflate()

    @Suppress("DEPRECATION")
    private fun ConnectivityManager.isCurrentlyConnected() = when {
        VERSION.SDK_INT >= VERSION_CODES.M ->
            activeNetwork
                ?.let(::getNetworkCapabilities)
                ?.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)

        else -> activeNetworkInfo?.isConnected
    } ?: false
}