即使Android M上的移动数据处于打开状态(有连接)，也可以通过WiFi(无连接)发送请求

Question

我必须将UDP数据包发送到没有互联网连接的WiFi模块（自带AP），但当我将手机与AP连接时，Android会在移动数据接口上重定向我的数据包，因为它已经连接到互联网。

我已经使用下面的代码来完成我的工作，但它似乎不适用于Android M.

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void setWifiInterfaceAsDefault() {
    ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkRequest.Builder builder = new NetworkRequest.Builder();
    NetworkRequest networkRequest= builder.addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED)
            .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
            .build();
    connectivityManager.requestNetwork(networkRequest, new ConnectivityManager.NetworkCallback());
}

我还添加了

<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />

在我的AndroidManifest.xml上，我确保Settings.System.canWrite(this)返回true，但仍然没有。

提前谢谢。

Answer 1

Stanislav的答案是正确的，但不完整，因为它只适用于棒棒糖。

我已经为棒棒糖和棉花糖编写了一个完整的解决方案，当连接到您选择的特定网络时，您可以通过WiFi路由所有网络请求。

---

Kotlin

在您的活动中，

@RequiresApi(Build.VERSION_CODES.LOLLIPOP)
class RoutingActivity : Activity() {
    private var mConnectivityManager: ConnectivityManager? = null
    private var mNetworkCallback: ConnectivityManager.NetworkCallback? = null
    //...
    override fun onCreate(savedInstanceState: Bundle?) {
        //...
        routeNetworkRequestsThroughWifi("Access-Point-SSID-You-Want-To-Route-Your-Requests")
    }

通过WiFi路由应用程序的未来网络请求（即使给定的WiFi网络没有互联网，移动数据有互联网连接）

/**
 * This method sets a network callback that is listening for network changes and once is
 * connected to the desired WiFi network with the given SSID it will bind to that network.
 *
 * Note: requires android.permission.INTERNET and android.permission.CHANGE_NETWORK_STATE in
 * the manifest.
 *
 * @param ssid The name of the WiFi network you want to route your requests
 */
private fun routeNetworkRequestsThroughWifi(ssid: String) {
    mConnectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    // ensure prior network callback is invalidated
    unregisterNetworkCallback(mNetworkCallback)
    // new NetworkRequest with WiFi transport type
    val request = NetworkRequest.Builder()
            .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
            .build()
    // network callback to listen for network changes
    mNetworkCallback = object : ConnectivityManager.NetworkCallback() {
        // on new network ready to use
        override fun onAvailable(network: Network) {
            if (getNetworkSsid(this@RoutingActivity).equals(ssid, ignoreCase = false)) {
                releaseNetworkRoute()
                createNetworkRoute(network)
            } else {
                releaseNetworkRoute()
            }
        }
    }
    mConnectivityManager?.requestNetwork(request, mNetworkCallback)
}

注销网络回调

private fun unregisterNetworkCallback(networkCallback: ConnectivityManager.NetworkCallback?) {
    if (networkCallback != null) {
        try {
            mConnectivityManager?.unregisterNetworkCallback(networkCallback)
        } catch (ignore: Exception) {
        } finally {
            mNetworkCallback = null
        }
    }
}

创建网络路由

private fun createNetworkRoute(network: Network): Boolean? {
    var processBoundToNetwork: Boolean? = false
    when {
    // 23 = Marshmallow
        Build.VERSION.SDK_INT >= 23 -> {
            processBoundToNetwork = mConnectivityManager?.bindProcessToNetwork(network)
        }
    // 21..22 = Lollipop
        Build.VERSION.SDK_INT in 21..22 -> {
            processBoundToNetwork = ConnectivityManager.setProcessDefaultNetwork(network)
        }
    }
    return processBoundToNetwork
}

释放网络路由

private fun releaseNetworkRoute(): Boolean? {
    var processBoundToNetwork: Boolean? = false
    when {
    // 23 = Marshmallow
        Build.VERSION.SDK_INT >= 23 -> {
            processBoundToNetwork = mConnectivityManager?.bindProcessToNetwork(null)
        }
    // 21..22 = Lollipop
        Build.VERSION.SDK_INT in 21..22 -> {
            processBoundToNetwork = ConnectivityManager.setProcessDefaultNetwork(null)
        }
    }
    return processBoundToNetwork
}

Helper

private fun getNetworkSsid(context: Context?): String {
    // WiFiManager must use application context (not activity context) otherwise a memory leak can occur
    val mWifiManager = context?.applicationContext?.getSystemService(Context.WIFI_SERVICE) as WifiManager
    val wifiInfo: WifiInfo? = mWifiManager.connectionInfo
    if (wifiInfo?.supplicantState == SupplicantState.COMPLETED) {
        return wifiInfo.ssid.removeSurrounding(""")
    }
    return ""
}

Answer 2

使用ConnectivityManager绑定网络。setProcessDefaultNetwork（）可防止漫游并允许完全TCP访问。因此，在onAvailable（）回调中，您可以将应用程序进程绑定到该网络，而不是打开到特定URL的连接。

ConnectivityManager connection_manager = 
(ConnectivityManager) activity.getApplication().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkRequest.Builder request = new NetworkRequest.Builder();
request.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
connection_manager.registerNetworkCallback(request.build(), new NetworkCallback() {
    @Override
    public void onAvailable(Network network) {
        ConnectivityManager.setProcessDefaultNetwork(network);
    }
}

原始答案