ネットワーク監視機構実装

はじめに

今回はAndroidにおけるネットワーク監視の共通処理を実装してみようと思います

コード

fun Context.isOnline(): Boolean {
    val connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as? ConnectivityManager
    return connectivityManager?.getNetworkCapabilities(connectivityManager.activeNetwork)?.run {
        when {
            hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
            hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
            hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
            hasTransport(NetworkCapabilities.TRANSPORT_VPN) -> true
            else -> false
        }
    } ?: false
}
@Singleton
class NetworkConnectivityChecker @Inject constructor(
    @ApplicationContext private val context: Context,
) {
    private val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager

    // ネットワーク状態を Flow で公開
    private val _networkState = MutableStateFlow(context.isOnline())
    val networkState: StateFlow<Boolean> = _networkState.asStateFlow()

    init {
        registerNetworkCallback()
    }

    private fun registerNetworkCallback() {
        try {
            val networkRequest = NetworkRequest.Builder()
                .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
                .build()

            val callback = object : ConnectivityManager.NetworkCallback() {
                override fun onAvailable(network: Network) {
                    _networkState.value = true
                }

                override fun onLost(network: Network) {
                    // 他のネットワークがまだ有効かどうかを確認
                    // Wi-Fi ↔ モバイルネットワークの切り替え時に誤ってfalseにならないようにする
                    _networkState.value = context.isOnline()
                }

                override fun onCapabilitiesChanged(
                    network: Network,
                    networkCapabilities: NetworkCapabilities,
                ) {
                    val hasInternet = networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
                    val hasValidated = networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
                    _networkState.value = hasInternet && hasValidated
                }
            }

            connectivityManager.registerNetworkCallback(networkRequest, callback)
        } catch (e: Exception) {
           
        }
    }
}

最後に

復帰時にすぐ更新をかけたい時などに役立つと思います