使Android同时使用WiFi与设备通话和移动数据与服务器通话? [英] Make Android simultaneously use WiFi to talk to a device and mobile data to talk to a server?

问题描述

我正在开发一个Android应用程序，该应用程序通过Wifi连接到OBD2设备，并且该应用程序可以读取速度，RPM，发动机冷却液温度等详细信息.因此wifi仅用于与OBD2设备连接(它不具备连接互联网，仅用于与本地客户进行通信).我还需要Internet连接才能使用Web服务.但是连接了wifi后，我无法通过android中的移动数据网络连接互联网.

I'm developing an Android application which connects to an OBD2 device by Wifi and app can read Speed, RPM, Engine coolant temperature details etc. So wifi is used only for connecting with the OBD2 device(it doesn't have facility to connect with internet, only for communication with local clients). I also need an internet connection for web services. But after connecting my wifi I am not able to connect internet via my mobile data network in android.

也为iOS开发了类似的应用程序.在iOS中，我可以使用Wifi上的设备(静态Wifi设置)和来自蜂窝网络的Internet连接.这意味着使用一些静态IP配置我的wifi，这样我就可以在iOS中使用移动数据网络进行Internet连接.

The similar application is also developed for iOS. In iOS, I can use device over Wifi (Static Wifi setting) and Internet connection from my cellular network. It means configure my wifi with some static ip I am able to use mobile data network for Internet connection in iOS.

但是在Android中，如果我使用静态wifi并检查Internet连接，则无法使用.

But in Android, If I use static wifi and check for Internet connection, it is not available.

如何通过在android中配置wifi设置来同时使用Wifi和Internet连接并行运行或以其他任何方式运行?

How can I use Wifi and Internet connection both run parallel or any other way by configuring wifi settings in android ?

推荐答案

首先，我们在这里可能面临的问题是，由于WiFi网络上没有互联网连接，因此HTTP数据将无法通过该连接.参见通过WiFi(无连接)，即使Android M上的移动数据处于打开状态(有连接)作为解决方案

Firstly, the problem we may face here is that because there is no internet connection on WiFi network, HTTP data will not go through that connection. See Send request over WiFi (without connection) even if Mobile data is ON (with connection) on Android M for solution

但是，我遇到了有时没有HTTP请求成功的问题.要解决此问题，我们可以使用

However, I have faced issue where sometimes no HTTP request is successful. To solve this problem, we can use ConnectivityManager.requestNetwork() and Network.openConnection() to achieve this.

确保已启用移动数据和WiFi网络，并且Android Manifest具有正确的连接:

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />

变量:

private ConnectivityManager.NetworkCallback mWifiNetworkCallback, mMobileNetworkCallback;
private Network mWifiNetwork, mMobileNetwork;

获取连接管理器:

final ConnectivityManager manager = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);

构建网络回调:

if(mWifiNetworkCallback == null){
    //Init only once
    mWifiNetworkCallback = new ConnectivityManager.NetworkCallback() {
        @Override
        public void onAvailable(final Network network) {
            try {
                //Save this network for later use
                mWifiNetwork = network;
            } catch (NullPointerException npe) {
                npe.printStackTrace();
            }
        }
    };
}

if(mMobileNetworkCallback == null){
    //Init only once
    mMobileNetworkCallback = new ConnectivityManager.NetworkCallback() {
        @Override
        public void onAvailable(final Network network) {
            try {
                //Save this network for later use
                mMobileNetwork = network;
            } catch (NullPointerException npe) {
                npe.printStackTrace();
            }
        }
    };
}

请求网络

NetworkRequest.Builder wifiBuilder;
wifiBuilder = new NetworkRequest.Builder();
//set the transport type do WIFI
wifiBuilder.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
manager.requestNetwork(wifiBuilder.build(), mWifiNetworkCallback);

NetworkRequest.Builder mobileNwBuilder;
mobileNwBuilder = new NetworkRequest.Builder();
//set the transport type do Cellular
mobileNwBuilder.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR);
manager.requestNetwork(mobileNwBuilder.build(), mMobileNetworkCallback);

像这样发出适当的请求:

public void makeHTTPRequest(final String httpUrl, final String payloadJson, final int timeout,
                          final boolean hasHeaders, final String header1, final String header2) {

    try {
        URL url = new URL(httpUrl);
        HttpURLConnection conn = null;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
            conn = (HttpURLConnection) mWifiNetwork.openConnection(url);

            //Or use mMobileNetwork, if and when required
            //conn = (HttpURLConnection) mMobileNetwork.openConnection(url);
        } else {
            conn = (HttpURLConnection) url.openConnection();
        }
        conn.setRequestProperty("Content-Type", "application/json");
        conn.setReadTimeout(timeout * 1000);
        conn.setConnectTimeout(timeout * 1000);

        conn.setDoInput(true);
        conn.setDoOutput(true);

        if(hasHeaders){
            conn.setRequestProperty("header1", header1);
            conn.setRequestProperty("header2", header2);

        }
        conn.setRequestMethod("PUT");

        OutputStream os = conn.getOutputStream();
        os.write(payloadJson.getBytes());
        os.close();

        final int responseCode = conn.getResponseCode();

        if (responseCode == HttpURLConnection.HTTP_OK) {
            final String statusMessage = conn.getResponseMessage();
            //Log this
        } 
    } catch (SocketException se){
        se.printStackTrace();
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}

注意: 这些功能可从Android Lollipop及更高版本使用.因此，有必要在适当的地方使用Build.Version.SDK_INT，如下所示:

Note: These functions are avaialble from Android Lollipop and above. So, it is necessary to use Build.Version.SDK_INT at appropriate place, like this:

if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {

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