java - 当 WiFi 和蜂窝数据在 Android Studio 中连接时，如何以编程方式分别对两者执行网络操作？

Question

此代码用于连接到地址为 192.168.22.1 的 wifi 屏幕。当移动数据关闭时，它工作正常，但如果移动数据打开，则无法工作:

public void onConnectClicked(View view){
        Y2Screen screen = new Y2Screen("http://192.168.22.1");
        final TextView message=findViewById(R.id.mess);
        try {
            message.setText("Connecting....");
            if (!screen.login("guest", "guest")) {
                message.setText("Connection Failed");
            } else {
                message.setText("Done Loging.");
                //VideoArea va = new VideoArea(0, 0, screen.getWidth(), screen.getHeight());
                PicArea pa=new PicArea(0, 0, screen.getWidth(), screen.getHeight());


                File dir = Environment.getExternalStorageDirectory();
                String path = dir.getAbsolutePath();


                //va.addVideo(path+"/glomo/image.jpeg", 100);
                pa.addPage(path+"/glomo/test3.png","PNG");
                ProgramPlayFile prog = new ProgramPlayFile(1);
                prog.getAreas().add(pa);
                String listId = screen.writePlaylist(new ProgramPlayFile[]{prog});
                screen.play(listId);

            }
        } catch (Y2Exception e) {
            e.printStackTrace();
        }
    }

Answer 1

可能是因为 192.168.22.1 是本地地址，所以只能从本地网络(wifi，...)访问它。如果您使用移动连接数据，则您位于公共(public)互联网上，因此您需要将该本地地址 NAT 到公共(public)地址端口。

您可以使用以下方式检测连接类型:

ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = cm.getActiveNetworkInfo();

更多信息请访问 Detect network connection type on Android关于 NAT 问题:Get the NAT translated IP and port of some local port和 How to expose my localhost to the WWW? (port forwarding?)

如果两个连接都处于 Activity 状态，则从connectivityManager.getAllNetworks() 循环所有网络，并使用connectivityManager.bindProcessToNetwork(network) 选择一个；

for (Network network : connectivityManager.getAllNetworks()) {
  NetworkInfo networkInfo = connectivityManager.getNetworkInfo(network);
  if (networkInfo.getType() == ConnectivityManager.TYPE_ETHERNET || networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
    connectivityManager.bindProcessToNetwork(network);
    break;
  }
}

参见Use multiple network interfaces in an app