好吧，我已经想通了，不久后，我张贴了这个问题。 这code在这里工作得很好：

Ok, I have figured out soon after I posted this question. This code here works fine:

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://192.168.192.131/");

try {
    StringEntity se = new StringEntity( "<aaaLogin inName=\"admin\" inPassword=\"admin123\"/>", HTTP.UTF_8);
    se.setContentType("text/xml");
    httppost.setEntity(se);

    HttpResponse httpresponse = httpclient.execute(httppost);
    HttpEntity resEntity = httpresponse.getEntity();
    tvData.setText(EntityUtils.toString(resEntity));        
} catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}