Articles are assigned to categories, and menu link items are used to open the category or article, which displays in the content area of the website. Most websites have specific articles to be displayed on the front page, and these articles may be assigned to one, or different categories.
The majority of the content on a Joomla! website consists of articles. Articles are assigned to categories, regardless of its hierarchy or level. Subcategories (child categories) can be created and associated with any Category above (a parent category). There is no limit to the number of categories or subcategories that can be created.
There are several steps required so that sorting works properly. The state variables list.ordering and list.direction are used to store the ordering column and ordering direction (ascending or descending).
Joomla! comes with many installed modules. A Joomla! installation can have a number of modules that are installed but have not been included as functional content elements. This means that a module extension can be installed by the Extensions Manager, but not yet included to be part of a web page.
The calendar form field type provides a text box for entry of a date. An icon next to the text box provides a link to a pop-up calendar, which can also be used to enter the date value. If the field has a saved value this is shown in the text box. Otherwise the default value, if any, is displayed.
Accessing user information (like name, username, registered date) is very simple process in Joomla. getUser function of JFactory class returns a reference to the global user object. You can use this information about the current user in any part of your Joomla! extension. You only need to fetch the object and access the member variables.
The main entry point, helloworld.php, passes control to the controller, which handles performing the task that was specified in the request. At present, the component specific controller doesn't do anything more than the parent class already does, which is why the controller class is empty.
The view asks the model for the item. In the model, you need the id of the item for querying the database. You can get this id from the Joomla system URL and store it as a state variable in the populateState(). You can also load the global parameters in the state variable.
If you like to change the way a Joomla! Extension is displayed on your site, you can either re-code the extension from the scratch or you can use overrides. The standard output from any Joomla module or component can be overridden by adding code to the html directory of your template.
The checkboxes form field type provides a set of checkboxes. Unlike most standard form field types, such as textfield or checkbox, this field is little different. It will create checkboxes, and submit their values in form of an array, but it will not store them in the database.
The groupedlist form field type provides a drop down list or a list box of custom-defined entries which has the ability to show grouped data. If the field has a saved value this is selected when the page is first loaded. If not, the default value (if any) is selected.
The imagelist form field type provides a drop down list of image files in a specified directory. Only files with .png, .gif, .jpg, .bmp, .ico extensions are listed. If the field has a saved value, this is selected when the page is first loaded. If not, the default value (if any) is selected.
The media form field type provides modal access to the media manager for the choice of an image. Users with appropriate permissions will be able to upload files. If the user is not authorised to view or add media they will see an error page in the modal popup.
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