try
{
	URL url = new URL(getString(R.string.serverurl));
	HttpURLConnection conn = (HttpURLConnection) url.openConnection();
	conn.setRequestMethod("GET");
	conn.setConnectTimeout(5000);

	int code = conn.getResponseCode();
	if (code == 200)
	{
		InputStream is = conn.getInputStream();
		updateInfo = UpdateInfoParser.getUpdateInfos(is);
		if (updateInfo != null)
		{
			if (getVersion().equals(updateInfo.getVersion()))
			{
				// 版本号相同，进入应用程序主界面
				msg.what = LOAD_MAIN_UI;
			}
			else
			{
				// 版本号不相同，提示用户更新应用程序
				msg.what = SHOW_UPDATE_INFO;
			}
		}
		else
		{
			// 解析xml失败
			msg.what = XML_PARSE_ERROR;
		}
	}
	else
	{
		// 服务器错误，资源没找到
		msg.what = SERVER_ERROR;
	}
}
catch (MalformedURLException e)
{
	e.printStackTrace();
	msg.what = URL_ERROR;
}
catch (IOException e)
{
	e.printStackTrace();
	msg.what = NETWORK_ERROR;
}