Unable to parse and display result in Toast (Android)?

I am newbie in Android, so I am getting problem in JSON parsing on HTTP Request. Let me give a brief about that. Actually I am trying to make a login, from where a user will type "email" as username and "password" as passsword, as soon as he clicks on login button a http request will be made on url http://excoflare.com/dev2010/bb_snet/baranzan/index.php?json=json&UM_email="+sUserName+"&UM_password="+sPassword and if succeded a Toast message will arrive "Welcome username" on the same layout. I have two class (i) HelloAndroid.java and (ii) RestJsonClient.java

HelloAndroid.java

 public class HelloAndroid extends Activity implements OnClickListener {
                   /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle icicle) {
                         super.onCreate(icicle);
                         setContentView(R.layout.main);
                         Button login = (Button)findViewById(R.id.login_button);
                        login.setOnClickListener(this);
                     }

                     public void onClick(View v) {
                         EditText usernameEditText = (EditText) findViewById(R.id.txt_username);
                         EditText passwordEditText = (EditText) findViewById(R.id.txt_password);
                         String sUserName = usernameEditText.getText().toString();
                         String sPassword = passwordEditText.getText().toString();
                         String address = "http://excoflare.com/dev2010/bb_snet/baranzan/index.php?json=json&UM_email="+sUserName+"&UM_password="+sPassword+"";
                         JSONObject json = RestJsonClient.connect(address); 
                          /* is something missing here if yes Please HELP*/
                         next();
    开发者_StackOverflow                }

                     private void next(){
                         Toast.makeText(HelloAndroid.this, "Welcome username", Toast.LENGTH_SHORT).show();
                    }

                   }

RestJsonClient

public class RestJsonClient {

    public static JSONObject connect(String url)
    {

        HttpClient httpclient = new DefaultHttpClient();

        // Prepare a request object
        HttpGet httpget = new HttpGet(url); 

        // Execute the request
        HttpResponse response;

        JSONObject json = new JSONObject();

        try {
            response = httpclient.execute(httpget);

            HttpEntity entity = response.getEntity();

            if (entity != null) {

                // A Simple JSON Response Read
                InputStream instream = entity.getContent();
                String result= convertStreamToString(instream);

                json=new JSONObject(result);

                instream.close();
            }

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return json;
    }
    /**
     *
     * @param is
     * @return String
     */
    public static String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

}

Now i am trying with only correct/valid email and password, for now that only i want. PLEASE HELP. THANKS A LOT

JSONObject json = RestJsonClient.connect(address); 
                      /* is something missing here if yes Please HELP*/
                     next();

Here you should have a if-else condition to check the data that you are getting from the json response. in you case you should check the user authentication . The if the user is authenticate then you should show the Toast else not.