可以使用Android提供的ConnectivityManager类中的getActiveNetworkInfo方法来获取当前网络连接的信息，并从中获取域名。

具体代码示例如下：

ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected() && networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
    WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
    DhcpInfo dhcpInfo = wifiManager.getDhcpInfo();
    if (dhcpInfo != null) {
        String domainName = dhcpInfo.domainName;
        if (domainName != null && !domainName.isEmpty()) {
            // 域名
        }
    }
}