I am making an android application that connects to an external mysql database and i have a login and registration function working on it.
I have a table within my database called lessons and has the columns name and time in it. i have been searching for days of a way to read the database and display the contents of that table in listview but i can not find anything that works for me.
I realise there are a lot of similar question but i have not found any of them helpful and am really starting to struggle.
Here is my activity page:
package com.example.studentregister;
//imports
import com.example.studentregister.library.JSONParser;
import com.example.studentregister.R;
public class ProfilePage extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> lessonList;
// url to get all products list
private static String url_all_lessons = "http://192.168.0.6/android_login_api/get_all_lessons.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_LESSONS = "lessons";
private static final String TAG_PID = "uid";
private static final String TAG_NAME = "name";
// products JSONArray
JSONArray lessons = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.profilepage);
// Hashmap for ListView
lessonList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
ListView lv = getListView();
}
// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ProfilePage.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_lessons, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
lessons = json.getJSONArray(TAG_LESSONS);
// looping through All Products
for (int i = 0; i < lessons.length(); i++) {
JSONObject c = lessons.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
lessonList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
LoginActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
ProfilePage.this, lessonList,
R.layout.eachlesson, new String[] { TAG_PID,
TAG_NAME},
new int[] { R.id.uid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
Here are my two xml files:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<!-- Main ListView
Always give id value as list(@android:id/list)
-->
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<!-- Name Label -->
<TextView
android:id="@+id/name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="6dip"
android:paddingLeft="6dip"
android:textSize="17dip"
android:textStyle="bold" />
</LinearLayout>
The problem atm is that uid in the list adapter
new int[] { R.id.uid, R.id.name });
can not be resolved or is not a field. But i have had this example without that error on another project but nothing shows up on the page.
I'm not positive (when working with MySql on Android), but when working with sqlite, you have to have a filed called _id or it will not work. I would start with that in your mysql database. You also have to select that field when displaying data, or it will not work. I spent several hours dealing with this specific issue.
Maybe this blog can help you: http://nanang18nurhidayat.files.wordpress.com/2013/03/list-view-with-image-from-url-mysql-json-php.pdf
you should ad R.id.uid on second xml with R.id.name.why you don't create that id?