How to fetch user data in json when user is logged in?

Question

I am new in android.I want to fetch user information using Mysql ,when the user is logged in.But when i am going to second activity after login i am getting blank page.I have used NameValuePair to pass the value to php variable.

public class Messages extends BaseActivity {

    private String[] navMenuTitles;
    private TypedArray navMenuIcons;
    private EditText editTextName;
    SharedPreferences sp;
    private String jsonResult;
    private ListView listView;
    private Button b;
    EditText etname, et;
    TextView tv;
    String myJSON;

    private static final String TAG_RESULTS="result";
    private static final String TAG_NAME = "message_recd";
    private static final String TAG_ADD ="message_sent";

    JSONArray peoples = null;

    ArrayList<HashMap<String, String>> personList;

    ListView list;

    public static final String USER_NAME = "USERNAME";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_first);

        Intent intent = getIntent();
        String fName = intent.getStringExtra("fname");

        TextView textView = (TextView) findViewById(R.id.fname);

        textView.setText("Welcome "+fName);

        navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items); 

        navMenuIcons = getResources().obtainTypedArray(R.array.nav_drawer_icons);
        // load icons from
                                                            // strings.xml

        set(navMenuTitles, navMenuIcons);
        editTextName = (EditText) findViewById(R.id.editTextName);
        b=(Button)findViewById(R.id.button1);
        list = (ListView) findViewById(R.id.listView);
        personList = new ArrayList<HashMap<String,String>>();

        getData();

     }



        protected void showList(){
            try {
                JSONArray peoples = new JSONArray(myJSON);

                for(int i=0;i<peoples.length();i++){
                    JSONObject c = peoples.getJSONObject(i);
                    String name=null, address=null;
                    if(c.has("message_recd"))
                        name = c.getString("message_recd");
                    else if(c.has("message_sent"))
                        address = c.getString("message_sent");

                    HashMap<String,String> persons = new HashMap<String,String>();
                    persons.put(TAG_NAME,name);
                    persons.put(TAG_ADD,address);
                    personList.add(persons);
                }

                ListAdapter adapter = new SimpleAdapter(
                        Messages.this, personList, R.layout.list_item,
                        new String[]{TAG_NAME,TAG_ADD},
                        new int[]{R.id.name, R.id.address}
                );

                list.setAdapter(adapter);

            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        public void getData(){
            class GetDataJSON extends AsyncTask<String, Void, String>{

                @Override
                protected String doInBackground(String... params) {
                    DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams());
                    HttpPost httppost = new HttpPost("http://10.0.2.2/progress_card/testing.php");
                    httppost.setHeader("Content-type", "application/json");

                    InputStream inputStream = null;
                    String result = null;
                    try {
                        Intent intent1 = getIntent();
                        String fName = intent1.getStringExtra("fname");

                        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
                        nameValuePairs.add(new BasicNameValuePair("username", fName));
                        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
                        HttpEntity entity = response.getEntity();

                        inputStream = entity.getContent();
                        // json is UTF-8 by default
                        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
                        StringBuilder sb = new StringBuilder();

                        String line = null;
                        while ((line = reader.readLine()) != null)
                        {
                            sb.append(line + "\n");
                        }
                        result = sb.toString();
                    } catch (Exception e) {
                        // Oops
                    }
                    finally {
                        try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
                    }
                    return result;
                }

                @Override
                protected void onPostExecute(String result){
                    myJSON=result;
                    showList();
                }
            }
            GetDataJSON g = new GetDataJSON();
            g.execute();
        }
     }

My Logcat

09-23 01:57:45.436: W/System.err(1670): org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONArray
09-23 01:57:45.456: W/System.err(1670):     at org.json.JSON.typeMismatch(JSON.java:111)
09-23 01:57:45.456: W/System.err(1670):     at org.json.JSONArray.<init>(JSONArray.java:96)
09-23 01:57:45.476: W/System.err(1670):     at org.json.JSONArray.<init>(JSONArray.java:108)
09-23 01:57:45.476: W/System.err(1670):     at com.pitechnologies.progresscard.Messages.showList(Messages.java:107)
09-23 01:57:45.476: W/System.err(1670):     at com.pitechnologies.progresscard.Messages$1GetDataJSON.onPostExecute(Messages.java:180)
09-23 01:57:45.486: W/System.err(1670):     at com.pitechnologies.progresscard.Messages$1GetDataJSON.onPostExecute(Messages.java:1)
09-23 01:57:45.486: W/System.err(1670):     at android.os.AsyncTask.finish(AsyncTask.java:632)
09-23 01:57:45.486: W/System.err(1670):     at android.os.AsyncTask.access$600(AsyncTask.java:177)
09-23 01:57:45.496: W/System.err(1670):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
09-23 01:57:45.506: W/System.err(1670):     at android.os.Handler.dispatchMessage(Handler.java:102)
09-23 01:57:45.506: W/System.err(1670):     at android.os.Looper.loop(Looper.java:136)
09-23 01:57:45.516: W/System.err(1670):     at android.app.ActivityThread.main(ActivityThread.java:5001)
09-23 01:57:45.516: W/System.err(1670):     at java.lang.reflect.Method.invokeNative(Native Method)
09-23 01:57:45.516: W/System.err(1670):     at java.lang.reflect.Method.invoke(Method.java:515)
09-23 01:57:45.516: W/System.err(1670):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
09-23 01:57:45.516: W/System.err(1670):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
09-23 01:57:45.536: W/System.err(1670):     at dalvik.system.NativeStart.main(Native Method)

My Php Code

<?php
include "check.php";
define('HOST','localhost');
define('USER','root');
define('PASS','');
define('DB','progress_card');

$con = mysqli_connect(HOST,USER,PASS,DB);

$sql1 = "select * from student_detail where parentusername='".$username."'";
$res1 = mysqli_query($con,$sql1);

$row1=mysqli_fetch_array($res1);

$cl=$row1['class']."-".$row1['section'];
$sql2="select * from teachers where classassign='$cl'";
$res2 = mysqli_query($con,$sql2);

$row2=mysqli_fetch_array($res2);

$to=$row2['email'];
$from=$row1['parentemail'];



$result = array();

$sql = "select * from messages where to_email='".$to."' and from_email='".$from."'";
$res = mysqli_query($con,$sql);

while($row = mysqli_fetch_array($res))
{
array_push($result,array('message_recd'=>$row['message']));
}

$sqlw = "select * from messages where from_email='".$to."' and to_email='".$from."'";
$resw = mysqli_query($con,$sqlw);

while($row5 = mysqli_fetch_array($resw))
{

array_push($result,array('message_sent'=>$row5['message']));
}

//array_push($result,array('message_sent'=>"dfdsghdfgddfgdsd"));
//array_push($result,array('message_sent'=>"sfdsflkufhskfhdskjfsfssadfadsffsafasfsfsadfafsaf"));

//array_push($result,array('message_recd'=>$row1['parentemail'],'message_sent'=>$row2['email']));

echo json_encode($result);

mysqli_close($con);

?>

My php Response

[{"message_recd":"asdadasda"},{"message_recd":"hello"},{"message_recd":"how r u"},{"message_recd":"hello\n"},{"message_recd":"hello"},{"message_recd":"1"},{"message_recd":"qd"},{"message_recd":"1"},{"message_recd":"hello12"},{"message_recd":"hello again"},{"message_recd":"hey whtas up"},{"message_recd":"jhkwdfjdw"},{"message_recd":"is it working"},{"message_recd":"qw"},{"message_recd":"sdfsdfsdfsadf"},{"message_recd":"qwertyuiop"},{"message_recd":"aaaa"},{"message_sent":"hey whtas up"}]

Answer 1

Without seeing your response structure, I can assume you are returning something like this from your PHP page:

{
    "test": [
        {
            "data": "myData"
        }
    ]
}

Meaning you have a JSONArray inside of a JSONObject.

Try changing this line JSONArray peoples = new JSONArray(myJSON); to something like this JSONObject people = new JSONObject(myJSON); and then you can do something like this JSONArray peopleArray = people.getJSONArray("arrayKey");

Hope this helps!

edit:

Just saw your edited question (with the response), and that is a valid JSONArray, so you're probably doing something wrong when reading the response.

Change this line sb.append(line + "\n"); to this sb.append(line); and try again. Also see if your StringBuilder contains good data after you finish fetching the data!

edit 2:

Also, are you sure your API call returns data correctly (not giving you an error), since in the exception it says org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONArray, meaning your StringBuilder string starts with a html <br> tag.