我正在使用在Android 2.3.4上运行的三星Galaxy S Plus手机

我在设置 - >无线和网络 - > Wi-Fi设置 - >菜单按钮 - >高级面板中手动设置手机中的代理服务器和端口 .

我的手机仍然无法使用代理进行通信 . 我试过浏览器，但是无法使用代理设置 .

public static InputStream inputStreamForUrl(URL url) throws IOException {

        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); // doesn't work on android 2.3.4
        urlConnection.setRequestMethod("GET");
        urlConnection.setDoInput(true);
        urlConnection.setConnectTimeout(30000);
        urlConnection.setReadTimeout(30000);
        System.out.println(urlConnection.usingProxy());
        urlConnection.connect();
        return urlConnection.getInputStream();
}

但是，如果我在代码中手动硬编码代理，它就可以工作

Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.server.url", 8080));// this needs to be hard coded to make it work in 2.3
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(proxy);// this needs to be hard coded to make it work in 2.3

我试图动态找出系统代理，然后在代码中使用它，

private static void getProxySettings()
    {
        final boolean IS_ICS_OR_LATER = Build.VERSION.SDK_INT >= 14;

        String proxyAddress = "";
        int proxyPort = 0;

        if( IS_ICS_OR_LATER )
        {
            proxyAddress = System.getProperty( "http.proxyHost" );

            String portStr = System.getProperty( "http.proxyPort" );
            proxyPort = Integer.parseInt( ( portStr != null ? portStr : "-1" ) );
        }
        else
        {
            proxyAddress = android.net.Proxy.getHost( ctx );
            proxyPort = android.net.Proxy.getPort( ctx );
        }



        System.out.println(proxyAddress);
        System.out.println(proxyPort);
    }

但代理地址和端口始终为null .

请有人帮忙吗

PS. 我在Android 4.1 / 4.2 / 4.3设备上完全没问题

android proxy android-2.3-gingerbread