javasocket。getInetAddress（）不返回任何内容

Question

我使用以下代码从运行在安卓手机上的服务器所在的网络获取IP。 早些时候，同样的代码运行良好。现在它不会返回IP

注意：我没有对此代码进行任何更改

代码：

  public String getIpAddress() {
            String ip = "";
            try {
                Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
                        .getNetworkInterfaces();
                while (enumNetworkInterfaces.hasMoreElements()) {
                    NetworkInterface networkInterface = enumNetworkInterfaces
                            .nextElement();
                    Enumeration<InetAddress> enumInetAddress = networkInterface
                            .getInetAddresses();
                    while (enumInetAddress.hasMoreElements()) {
                        InetAddress inetAddress = enumInetAddress
                                .nextElement();

                        if (inetAddress.isSiteLocalAddress()) {
                            ip += "Server running at : "
                                    + inetAddress.getHostAddress();
                        }
                    }

                }

            } catch (SocketException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                ip += "Something Wrong! " + e.toString() + "\n";
            }
            return ip;
        }
    }
}