I am trying to learn more about MySQL and using Java (on Android) to access and retrieve information from a database on my WAMS server. The way my app is setup is that it has an initial login screen which also grabs the “uid” of the username that’s logging in (from a different table) and stores it.
Upon login (which is functional – I setup a toast notification that displays the retrieved username and uid of the user logging in), it goes to a new screen (dashboard.xml) which has a TextView field setup to display the retrieved data (from table posted below) associated with the stored “uid”. Here is the table I am trying to pull data from:
Now, I have setup a PHP file that queries my db for rows that are associated with a specific “uid”. I have tested this file using an HTML form.
$connect = mysql_connect($dbhost, $dbuser, $dbpass) or die("connection error");
mysql_select_db($dbdb)or die("database selection error");
//Retrieve the User ID
$uid = $_POST['uid'];
//Query
$query = mysql_query("SELECT * FROM node WHERE uid='$uid' AND type='goal'");
//store # of rows returned
$num_rows = mysql_num_rows($query);
if ($num_rows >= 1) {
while($results=mysql_fetch_assoc($query)) {
//Store the returned data into a variable
$output = $results;
//encode the returned data in JSON format
echo json_encode($output);
}
mysql_close();
}
The result I get by testing the PHP file using uid value of 1 is:
{“nid”:”1″,”vid”:”1″,”type”:”goal”,”language”:””,”title”:”test”,”uid”:”1″,”status”:”1″,”created”:”1342894493″,”changed”:”1342894493″,”comment”:”2″,”promote”:”1″,”moderate”:”0″,”sticky”:”1″,”tnid”:”0″,”translate”:”0″}
{“nid”:”2″,”vid”:”2″,”type”:”goal”,”language”:””,”title”:”test2″,”uid”:”1″,”status”:”1″,”created”:”1342894529″,”changed”:”1342894529″,”comment”:”2″,”promote”:”1″,”moderate”:”0″,”sticky”:”1″,”tnid”:”0″,”translate”:”0″}
{“nid”:”5″,”vid”:”5″,”type”:”goal”,”language”:””,”title”:”run”,”uid”:”1″,”status”:”1″,”created”:”1343506987″,”changed”:”1343506987″,”comment”:”2″,”promote”:”1″,”moderate”:”0″,”sticky”:”1″,”tnid”:”0″,”translate”:”0″}
{“nid”:”9″,”vid”:”9″,”type”:”goal”,”language”:””,”title”:”run to the
hills”,”uid”:”1″,”status”:”1″,”created”:”1343604338″,”changed”:”1343605100″,”comment”:”2″,”promote”:”0″,”moderate”:”0″,”sticky”:”0″,”tnid”:”0″,”translate”:”0″}
Now, I have written some android code which sets up httppost and is supposed to retrieve the “titles” in my database table. I know it is wrong (obviously since it doesn’t work) but I am confused as to what to do next.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class Dashboard extends Activity implements OnClickListener {
// variable declarations
String uid = "1";
// create textview to display retrieved data
TextView display;
HttpClient httpclient;
HttpPost httppost;
HttpResponse httpresponse;
HttpEntity httpentity;
ArrayList<NameValuePair> resultArray;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dashboard);
display = (TextView) findViewById(R.id.test);
// initialize HttpClient
httpclient = new DefaultHttpClient();
// initialize HttpPost
httppost = new HttpPost("http://192.168.1.112/android/fetch.php");
try {
// Create new List
List<NameValuePair> resultList = new ArrayList<NameValuePair>();
resultList.add(new BasicNameValuePair("uid", uid));
httppost.setEntity(new UrlEncodedFormEntity(resultList));
httpresponse = httpclient.execute(httppost);
httpentity = httpresponse.getEntity();
InputStream instream = entity.getContent();
try {
// store incoming stream in an array
JSONArray jArray = new JSONArray(streamToString(instream));
JSONObject jData = null;
for (int i = 0; i < jArray.length(); i++) {
jData = jArray.getJSONObject(i);
String goals = jData.getString("title");
display.setText(goals);
}
//} catch (JSONException e) {
//Toast.makeText(this, "No entries found", Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(this, e.toString(), Toast.LENGTH_LONG)
.show();
}
} catch (Exception e) {
e.printStackTrace();
Notifications error = new Notifications();
error.userPassErrorDialog();
}
}
private static String streamToString(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();
}
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
I get the following error when testing it in the Android emulator:
Any help or suggestions will be greatly appreciated.
In your Android app, you expect a JSONArray:
However, in your PHP file you only output multiple separate JSON objects instead of a real array. I think, you should collect all items from the database in an PHP array first and then encode and output it only once.
My PHP skills are a bit rusted, but I hope this one will work:
I would expect the output then to be like this (maybe without indentation):