J2.5 talk

Developing a MVC Component/Adding categories

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Revision as of 19:32, 13 January 2013 by Neo314 (Talk | contribs)

Why $query = new JDatabaseQuery; but not $query = &new JDatabaseQuery; ?

In ../models/fields/helloworld.php on line 29

If you use the line, $query = new JDatabaseQuery;, component works, but when helloworlds is added as menu item it causes the following error when item is clicked:

Fatal error: Cannot instantiate abstract class JDatabaseQuery in C:\xampp\htdocs\test_site\administrator\components\com_helloworld\models\fields\helloworld.php on line 29

Reverting back to code from part 11, $query = $db->getQuery(true);, does not throw error.

Just an observation.


People who are using Joomla >= 2.5.5. will probably encounter a problem with categories menu - buttons for basic user actions missing (such as "New", "Edit" etc.) The solution can be found here:

Additional explanation about the controller helloworld.php file changes would be helpful.

The controller helloworld.php file changes from

// set default view if not set
JRequest::setVar('view', JRequest::getCmd('view', 'HelloWorlds'));


// set default view if not set
$input = JFactory::getApplication()->input;
$input->set('view', $input->getCmd('view', 'HelloWorlds'));

without any explanation as to the changes.