public class TampilUser extends AppCompatActivity {

ListView listView;
CustomAdapter customAdapter;
ArrayList<User> user = new ArrayList<>();

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

    listView = (ListView) findViewById(R.id.listUser);

    getJSON("http://www.trigroupindonesia.com/php/read_user.php");
}

@Override
public void onResume() {
    super.onResume();

    getJSON("http://www.trigroupindonesia.com/php/read_user.php");
}

private void getJSON(final String urlWebService) {

    class GetJSON extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
            try {
                loadIntoListView(s);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

        @Override
        protected String doInBackground(Void... voids) {
            try {
                URL url = new URL(urlWebService);
                HttpURLConnection con = (HttpURLConnection) url.openConnection();
                StringBuilder sb = new StringBuilder();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
                String json;
                sb.setLength(0);
                while ((json = bufferedReader.readLine()) != null) {
                    sb.append(json + "n");
                }
                bufferedReader.close();
                con.disconnect();
                return sb.toString().trim();
            } catch (Exception e) {
                return null;
            }
        }
    }
    GetJSON getJSON = new GetJSON();
    getJSON.execute();
}

public void loadIntoListView(String json) throws JSONException {
    JSONArray jsonArray = new JSONArray(json);
    user = new ArrayList<>();
    user.clear();
    User u;
    for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject obj = jsonArray.getJSONObject(i);
        String email = obj.getString("email");
        String nama = obj.getString("nama");

        u = new User();
        u.setEmail(email);
        u.setNama(nama);

        user.add(u);
    }
    customAdapter = new CustomAdapter(getApplicationContext(),user);
    listView.setAdapter(customAdapter);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            String nama = customAdapter.user.get(position).getNama();
            String email = customAdapter.user.get(position).getEmail();
            Intent i = new Intent(getApplicationContext(), DetailUser.class);

            i.putExtra("email", email);
            i.putExtra("nama", nama);
            startActivityForResult(i, 0);
        }
    });
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
    getJSON("http://www.trigroupindonesia.com/php/read_user.php");
    customAdapter.notifyDataSetChanged();
    customAdapter.notifyDataSetInvalidated();
}
}

public View getView(int position, View convertView, ViewGroup parent) {

   if(convertView==null)
   {
       convertView=inflater.inflate(R.layout.daftar_user,parent,false);
   }
   TextView textView_email = (TextView) convertView.findViewById(R.id.textView_email);
   TextView textView_nama = (TextView) convertView.findViewById(R.id.textView_nama);

   textView_email.setText(user.get(position).getEmail());
   textView_nama.setText(user.get(position).getNama());

   return convertView;
}