Unknown Error: "null" when running an Httppost with Parameters

Question

Explanation:

I own a simple Android app, and also a Nodejs server. I have the following permissions on AndroidManifest.xml of my application:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET"/>

I am trying to perform an HTTP Post and a Local URL, but this generates an unknown error:null, when running HTTP Post. So I have no way of knowing what’s going on.

I’ve checked Logcat but no mistakes, just that mistake null of my Exception is appearing.

Here is the HTTP Post code:

HttpPost post = new HttpPost("http://192.168.25.32:8080/signup");
HttpParams params = new BasicHttpParams(); //eu estava usando Params, agora uso Pairs
List<NameValuePair> pairs = new ArrayList<NameValuePair>();
pairs.add(new BasicNameValuePair("name", "Teste2"));
pairs.add(new BasicNameValuePair("email", "[email protected]"));
pairs.add(new BasicNameValuePair("country", "Brazil"));
pairs.add(new BasicNameValuePair("user", "teste"));
pairs.add(new BasicNameValuePair("pass", "123456"));
post.setEntity(new UrlEncodedFormEntity(pairs));            
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(post); //aqui vai para a Exception

Question:

What am I doing wrong? How can I solve this problem ?

I would also like to know why this error is being generated.

Observing:

When accessing http://192.168.25.32:8080/signup I have an html registration form working right, from there to know that my Nodejs server is communicating right, and working, so I’m sure the error is on Android.

Answer 1

In my view your code is correct, but the codes I did I never put the port next to ip, try to remove the port you added the url and access only by ip and the /signup as follows:

HttpPost post = new HttpPost("http://192.168.25.32/signup");

then tell me if it worked.

Hugs.

Answer 2

1. Is the url accessible in the device browser? I believe this is not the case, because this is more common when using localhost that is not recognized by the device, even AVD.
2. Are you using a single thread to do the Post? By your code we cannot know this, but it is a possible answer.

Try to use Asynctask:

new TheTask().execute("http://192.168.25.32/signup");

And the class would look something like this:

class TheTask extends AsyncTask<String,String,String>
    {

@Override
protected String onPostExecute(Void result) {
    // TODO Auto-generated method stub
    super.onPostExecute(result);
    // update textview here
    textView.setText("Server message is "+result);
}

@Override
protected void onPreExecute() {
    // TODO Auto-generated method stub
    super.onPreExecute();
}

@Override
protected String doInBackground(String... params) {
     try
        {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost method = new HttpPost(params[0]);
            HttpResponse response = httpclient.execute(method);
            HttpEntity entity = response.getEntity();
            if(entity != null){
                return EntityUtils.toString(entity);
            }
            else{
                return "No string.";
            }
         }
         catch(Exception e){
             return "Network problem";
         }

}
}