强制Android在局域网wifi上使用3G而无需网络访问

时间:2012-01-13 01:36:15

标签: android wifi 3g

我有一个无线网络设置,没有互联网接入。只是连接到它的各种其他本地WiFi设备。 DHCP配置为不返回网关或DNS服务器。只有IP和网络掩码。

当我将我的机器人连接到这个无线网络AP时它连接正常,但手机上的所有互联网连接都停止工作。

我希望由于wifi没有网关设置,android应该意识到互联网无法通过该连接而应该通过3G连接进行路由,这是5条吧。

我也尝试在Android手机上设置静态IP,但这没有帮助。

此设置的主要原因是Android设备可以将此远程网络上的数据传输到基于互联网的服务器,因为它可以毫无问题地连接到本地设备。然而,一旦设置了wifi,3G端就会被打破。

有关如何解决此问题的任何想法?

5 个答案:

答案 0 :(得分:5)

经过一些编码和测试后,我合并了Squonk和this解决方案。这是我创建的课程:

package it.helian.exampleprj.network;

import java.net.InetAddress;
import java.net.UnknownHostException;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo.State;
import android.net.wifi.WifiManager;
import android.text.TextUtils;
import android.util.Log;

public class NetworkUtils {
    private static final String TAG_LOG = "ExamplePrj";

    Context context;
    WifiManager wifiMan = null;
    WifiManager.WifiLock wifiLock = null;

    public NetworkUtils(Context context) {
        super();
        this.context = context;
    }

    /**
     * Enable mobile connection for a specific address
     * @param context a Context (application or activity)
     * @param address the address to enable
     * @return true for success, else false
     */
    public boolean forceMobileConnectionForAddress(Context context, String address) {
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (null == connectivityManager) {
            Log.d(TAG_LOG, "ConnectivityManager is null, cannot try to force a mobile connection");
            return false;
        }

        //check if mobile connection is available and connected
        State state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
        Log.d(TAG_LOG, "TYPE_MOBILE_HIPRI network state: " + state);
        if (0 == state.compareTo(State.CONNECTED) || 0 == state.compareTo(State.CONNECTING)) {
            return true;
        }

        //activate mobile connection in addition to other connection already activated
        int resultInt = connectivityManager.startUsingNetworkFeature(ConnectivityManager.TYPE_MOBILE, "enableHIPRI");
        Log.d(TAG_LOG, "startUsingNetworkFeature for enableHIPRI result: " + resultInt);

        //-1 means errors
        // 0 means already enabled
        // 1 means enabled
        // other values can be returned, because this method is vendor specific
        if (-1 == resultInt) {
            Log.e(TAG_LOG, "Wrong result of startUsingNetworkFeature, maybe problems");
            return false;
        }
        if (0 == resultInt) {
            Log.d(TAG_LOG, "No need to perform additional network settings");
            return true;
        }

        //find the host name to route
        String hostName = extractAddressFromUrl(address);
        Log.d(TAG_LOG, "Source address: " + address);
        Log.d(TAG_LOG, "Destination host address to route: " + hostName);
        if (TextUtils.isEmpty(hostName)) hostName = address;

        //create a route for the specified address
        int hostAddress = lookupHost(hostName);
        if (-1 == hostAddress) {
            Log.e(TAG_LOG, "Wrong host address transformation, result was -1");
            return false;
        }
        //wait some time needed to connection manager for waking up
        try {
            for (int counter=0; counter<30; counter++) {
                State checkState = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
                if (0 == checkState.compareTo(State.CONNECTED))
                    break;
                Thread.sleep(1000);
            }
        } catch (InterruptedException e) {
            //nothing to do
        }
        boolean resultBool = connectivityManager.requestRouteToHost(ConnectivityManager.TYPE_MOBILE_HIPRI, hostAddress);
        Log.d(TAG_LOG, "requestRouteToHost result: " + resultBool);
        if (!resultBool)
            Log.e(TAG_LOG, "Wrong requestRouteToHost result: expected true, but was false");

        state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
        Log.d(TAG_LOG, "TYPE_MOBILE_HIPRI network state after routing: " + state);

        return resultBool;
    }

    /**
     * This method extracts from address the hostname
     * @param url eg. http://some.where.com:8080/sync
     * @return some.where.com
     */
    public String extractAddressFromUrl(String url) {
        String urlToProcess = null;

        //find protocol
        int protocolEndIndex = url.indexOf("://");
        if(protocolEndIndex>0) {
            urlToProcess = url.substring(protocolEndIndex + 3);
        } else {
            urlToProcess = url;
        }

        // If we have port number in the address we strip everything
        // after the port number
        int pos = urlToProcess.indexOf(':');
        if (pos >= 0) {
            urlToProcess = urlToProcess.substring(0, pos);
        }

        // If we have resource location in the address then we strip
        // everything after the '/'
        pos = urlToProcess.indexOf('/');
        if (pos >= 0) {
            urlToProcess = urlToProcess.substring(0, pos);
        }

        // If we have ? in the address then we strip
        // everything after the '?'
        pos = urlToProcess.indexOf('?');
        if (pos >= 0) {
            urlToProcess = urlToProcess.substring(0, pos);
        }
        return urlToProcess;
    }

    /**
     * Transform host name in int value used by {@link ConnectivityManager.requestRouteToHost}
     * method
     *
     * @param hostname
     * @return -1 if the host doesn't exists, elsewhere its translation
     * to an integer
     */
    private int lookupHost(String hostname) {
        InetAddress inetAddress;
        try {
            inetAddress = InetAddress.getByName(hostname);
        } catch (UnknownHostException e) {
            return -1;
        }
        byte[] addrBytes;
        int addr;
        addrBytes = inetAddress.getAddress();
        addr = ((addrBytes[3] & 0xff) << 24)
                | ((addrBytes[2] & 0xff) << 16)
                | ((addrBytes[1] & 0xff) << 8 )
                |  (addrBytes[0] & 0xff);
        return addr;
    }

    @SuppressWarnings("unused")
    private int lookupHost2(String hostname) {
        InetAddress inetAddress;
        try {
            inetAddress = InetAddress.getByName(hostname);
        } catch (UnknownHostException e) {
            return -1;
        }
        byte[] addrBytes;
        int addr;
        addrBytes = inetAddress.getAddress();
        addr = ((addrBytes[3] & 0xff) << 24)


        | ((addrBytes[2] & 0xff) << 16)
            | ((addrBytes[1] & 0xff) << 8 )
            |  (addrBytes[0] & 0xff);
        return addr;
    }

    public Boolean disableWifi() {
        wifiMan = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
        if (wifiMan != null) {
            wifiLock = wifiMan.createWifiLock(WifiManager.WIFI_MODE_SCAN_ONLY, "HelianRCAWifiLock");
        }
        return wifiMan.setWifiEnabled(false);
    }

    public Boolean enableWifi() {
        Boolean success = false;

        if (wifiLock != null && wifiLock.isHeld())
            wifiLock.release();
        if (wifiMan != null)
        success = wifiMan.setWifiEnabled(true);
        return success;
    }
}

这是用法

使用代码

            boolean mobileRoutingEnabled = checkMobileInternetRouting();

            if(!mobileRoutingEnabled) {
                networkUtils.disableWifi();

                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

            networkUtils.forceMobileConnectionForAddress(context, RCA_URL);

            if(!mobileRoutingEnabled) {
                networkUtils.enableWifi();
            }

            // This second check is for testing purpose
            checkMobileInternetRouting();

            return callWebService(RCA_COMPLETE_URL, _plate);

其中 checkMobileInternetRouting 是:

private boolean checkMobileInternetRouting() {
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

    State state = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
    return 0 == state.compareTo(State.CONNECTED) || 0 == state.compareTo(State.CONNECTING);
}

使用程序

  1. 检查是否已启用到主机的路由
  2. 如果是,则无论wifi是否已连接,都要进行通信,并且仅执行第6点(第4点将仅检查路由是否已启用而不执行任何rilevant操作)。否则临时禁用wifi。
  3. 让3g连接回来的线程睡眠时间约为3秒
  4. 将3g路由设置为给定网址
  5. 启用wifi
  6. 现在即使没有网络访问的wifi连接也可以调用给定的URL
  7. 结论

    这有点hacky但工作正常。唯一的问题是这个路由有几秒的超时(如20-30),迫使你再次执行整个上述过程。将此超时设置为更高的值将非常好。

答案 1 :(得分:0)

从代码中,当您检测到没有连接时,您可以关闭WiFi ...

至于设置,没有(没有好的方法来检查是否确实存在普遍可靠的连接)。但有些手机会自动执行您所描述的内容,例如我的LG P-970。

(注意:当Android连接到WiFi时,Android会断开与移动网络的连接,因此无法通过移动设备连接到WiFi但通过移动设备进行互联网访问,即使Linux可以执行此操作(使用{{1}工具套件))

答案 2 :(得分:0)

我不能保证这会有效,因为这是我前一段时间才进行的实验。当无线连接网络无法通往外界时,我也有类似的需要使用3G(或其他移动网络)。

以下代码应删除wifi连接以允许移动网络进入播放。你需要在整个过程中进行各种测试,然后再重新建立wifi连接......

WifiManager wifiMan = null;
WifiManager.WifiLock wifiLock = null;

private Boolean disableWifi() {
    wifiMan = (WifiManager) getSystemService(Context.WIFI_SERVICE);
    if (wifiMan != null) {
        wifiLock = wifiMan.createWifiLock(WifiManager.WIFI_MODE_SCAN_ONLY, "MyWifiLock");
    }
    return wifiMan.setWifiEnabled(false);
}

private Boolean enableWifi() {
    Boolean success;

    if (wifiLock != null)
        wifiLock.release();
    if (wifiMan != null)
        success = wifiMan.setWifiEnabled(true);
    return success;
}

答案 3 :(得分:0)

Google为此目的在Android SDK 21中添加了一些有用的方法。

您可以创建NetworkRequest

NetworkRequest networkRequest = new NetworkRequest.Builder()
    .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
    .build();

然后您可以使用ConnectivityManager请求此类网络。例如,您希望确保所有HTTP请求都将通过具有Internet访问权限的网络传递。您可以通过以下方式构建Retrofit API:

ApiConfig apiConfig;

ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

connectivityManager.requestNetwork(networkRequest, new ConnectivityManager.NetworkCallback() {
    @Override
    public void onAvailable(Network network) {
        apiConfig = new Retrofit.Builder()
            .baseUrl("https://api.imatrix.io/")
            .client(new OkHttpClient.Builder()
                .socketFactory(network.getSocketFactory())
                .build())
            .build()
            .create(ApiConfig.class);
    }

    @Override
    public void onLost(Network network) {
        apiConfig = null; 
    }
});

请注意使用此类代码段时的线程安全性。

此外,我建议您检查ConnectivityManager#bindProcessToNetwork和此blog

ConnectivityManager.NetworkCallback是一个空类,它有several methods

答案 4 :(得分:-1)

您不需要编码任何东西。我找到了一个完全正确的应用程序。如果此连接没有互联网,您可以配置为自动断开连接。

https://play.google.com/store/apps/details?id=com.nLabs.internetconnectivity&hl=en