Zen-Dreams

As a reminder, this article is the fourth of a series called Write your own plugin for Wordpress

1. Introduction to plugins
2. Plugin’s skeletton
3. Activation, Hooks & Filters
4. Widgets Definition

1. Widgets definition

A widget is, in fact, a plugin that will allow users to display a block on their sidebar. That being said, there are only one action to use in order to create a Widget.

This action is called widgets_init - therefore you can call it like this : add_action(’widgets_init’, function_name);

Once you have done this, you will have to register two other functions inside this function_name function only if sidebars are available with your wordpress install.

Here is some code that can do the trick :

function function_name() {
	if ( !function_exists('register_sidebar_widget') || !function_exists('register_widget_control') )
		return;
	register_sidebar_widget(string $name,callback $function);
	// register_sidebar_widget takes the name of the widget and the function that will be used to display it.
	register_widget_control(string $name, callback $function2);
	// register_widget_control takes the name of the widget and the function that will be used to to change options (in the design panel).
}

That’s pretty all you need to know for Widgets. All the rest is non widget specific (options, actions and filters, api calls)

2. Sample Widget

Here below you will find a sample widget in written in fully object oriented php - not there is no option tab. This widget will only display a Simple Hello World with widget title customisable.

/*
Plugin Name: ZenDreams_Sample_Widget
Plugin URI: http://www.zen-dreams.com/
Description: Sample Widget
Version: 1.0
Author: Anthony PETITBOIS
Author URI: http://www.zen-dreams.com/
*/
class myWidget {

	function myWidget() {
		add_action('widgets_init', array(& $this, 'init_widget'));
	}

	function init_widget() {
		if ( !function_exists('register_sidebar_widget') || !function_exists('register_widget_control') )
			return;
		register_sidebar_widget(array('myWidget','widgets'),array(& $this, 'widget'));
		register_widget_control(array('myWidget', 'widgets'), array(& $this, 'widget_options'));
	}

	function widget($args) {
		global $wpdb;

		$WidgetTitle=get_option('mywidget_options');
		extract($args);

		echo $before_widget.$before_title.$WidgetTitle.$after_title;
		echo 'Hello World !';
		echo $after_widget;
	}

	function widget_options() {
		if ($_POST['mywidget_options']) {
			$option=$_POST['mywidget_options'];
			update_option('mywidget_options',$option);
		}
		$option=get_option('mywidget_options');
		echo '<label for="mywidget_options">Title : <input id="mywidget_options" name="mywidget_options" type="text" value="'.$option.'" /></label>';
	}
}
$myWidgetVariable= new myWidget ();