Android 用于网络状态判断的NetworkCapabilities的3种解决方案

前言

如今在Android 7.0版本以上判断网络是否可用，一般采用会ConnectivityManager.NetworkCallback，对其回调内NetworkCapabilities包含的Transports或Capabilities进行判断的方案，Android官方文档。经测试，有3中方案可行。

例如以下是一次状态回调包含的内容：

Transports: WIFI|VPN // 这个尤为重要
Capabilities:
NOT_METERED
&INTERNET
&NOT_RESTRICTED
&TRUSTED
&VALIDATED
&NOT_ROAMING
&FOREGROUND
&NOT_CONGESTED
&NOT_SUSPENDED
LinkUpBandwidth>=176231Kbps LinkDnBandwidth>=176231Kbps
AdministratorUids: []
RequestorUid: -1
RequestorPackageName: null

使用方法

// 在onResume调用
private void registerNetworkStatus() {
        Context context = getContext();
        if (context != null) {
            ConnectivityManager networkService = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                networkService.registerDefaultNetworkCallback(networkCallback);
            } else {
                networkService.registerNetworkCallback(new NetworkRequest.Builder().build(), networkCallback);
            }
        }
    }

// 在onPause调用
private void unRegisterNetworkStatus() {
        Context context = getContext();
        if (context != null) {
            ConnectivityManager networkService = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            networkService.unregisterNetworkCallback(networkCallback);
        }
    }

// 监听回调
private final ConnectivityManager.NetworkCallback networkCallback = new ConnectivityManager.NetworkCallback(){
        @Override
        public void onCapabilitiesChanged(@NonNull Network network, @NonNull NetworkCapabilities networkCapabilities) {
            super.onCapabilitiesChanged(network, networkCapabilities);
            Log.d(TAG, "onCapabilitiesChanged: 网络状态改变--->" + networkCapabilities.toString());
            if (NetworkUtils.isEnableToNetwork(getContext(), networkCapabilities)) {
                Log.d(TAG, "onCapabilitiesChanged ---> 网络可用");
            }
        }
    };

 /**
     * 检测网络连接状态是否可用，这里采用的第一种方案
     * 以下是可用网络: 
     *      NetworkCapabilities.TRANSPORT_CELLULAR,
     *      NetworkCapabilities.TRANSPORT_WIFI,
     *      NetworkCapabilities.TRANSPORT_BLUETOOTH,
     *      NetworkCapabilities.TRANSPORT_ETHERNET,
     *      NetworkCapabilities.TRANSPORT_VPN,
     *      NetworkCapabilities.TRANSPORT_WIFI_AWARE,
     *      NetworkCapabilities.TRANSPORT_LOWPAN
     */
    @SuppressLint("WrongConstant")
    public static boolean isEnableToNetwork(Context context, NetworkCapabilities networkCapabilities) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
            if (context == null) return false;
            ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            if (cm == null) return false;
                NetworkInfo mWiFiNetworkInfo = cm.getActiveNetworkInfo();
                return mWiFiNetworkInfo != null &&
                        (mWiFiNetworkInfo.getType() == ConnectivityManager.TYPE_WIFI || mWiFiNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE);
        } else {
            return networkCapabilities != null &&
                    networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
                    && networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED);

方案一、使用Capabilities

NetworkCapabilities.hasCapability()

方案二、使用Transports

NetworkCapabilities.hasTransport()
以下都是可用的网络，根据实际需求使用（基本上所有情况都符合实际需求）：

NetworkCapabilities.TRANSPORT_CELLULAR
NetworkCapabilities.TRANSPORT_WIFI
NetworkCapabilities.TRANSPORT_BLUETOOTH
NetworkCapabilities.TRANSPORT_ETHERNET
NetworkCapabilities.TRANSPORT_VPN
NetworkCapabilities.TRANSPORT_WIFI_AWARE
NetworkCapabilities.TRANSPORT_LOWPAN

方案三、使用LinkUpBandwidth和LinkDnBandwidth

判断上下行的网络速率，如果不可用的话不会超过100kbps

另外提醒：hasCapability 和 hasTransport 不要用错了