class-widget-name.php

<?php
/**
 * Plugin Name.
 *
 * @package   Plugin_Name
 * @author    Your Name <email@example.com>
 * @license   GPL-2.0+
 * @link      http://example.com
 * @copyright 2014 Your Name or Company Name
 */

// TODO: change 'Widget_Name' to the name of your plugin
class Widget_Name extends WP_Widget {

	/*--------------------------------------------------*/
	/* Constructor
	/*--------------------------------------------------*/

	/**
	 * Specifies the classname and description, instantiates the widget,
	 * loads localization files, and includes necessary stylesheets and JavaScript.
	 */
	public function __construct() {

		// TODO: update widget-name-id, classname and description
		// TODO: replace 'widget-name-locale' to be named more plugin specific. Other instances exist throughout the code, too.
		parent::__construct(
			'widget-name-id', // <-- Change this
			__( 'Widget Name', 'plugin-name' ),
			array(
				'classname'  => 'widget-name-class',
				'description' => __( 'Short description of the widget goes here.', 'plugin-name' )
			)
		);

		// Refreshing the widget's cached output with each new post
		add_action( 'save_post',    array( $this, 'flush_widget_cache' ) );
		add_action( 'deleted_post', array( $this, 'flush_widget_cache' ) );
		add_action( 'switch_theme', array( $this, 'flush_widget_cache' ) );

	} // end constructor

	/*--------------------------------------------------*/
	/* Widget API Functions
	/*--------------------------------------------------*/

	/**
	 * Outputs the content of the widget.
	 *
	 * @param array args  The array of form elements
	 * @param array instance The current instance of the widget
	 */
	public function widget( $args, $instance ) {

		
		// Check if there is a cached output
		$cache = wp_cache_get( 'widget-name-id', 'widget' );

		if ( !is_array( $cache ) )
			$cache = array();

		if ( ! isset ( $args['widget_id'] ) )
			$args['widget_id'] = $this->id;

		if ( isset ( $cache[ $args['widget_id'] ] ) )
			return print $cache[ $args['widget_id'] ];
		
		// go on with your widget logic, put everything into a string and …


		extract( $args, EXTR_SKIP );

		$widget_string = $before_widget;

		// TODO: Here is where you manipulate your widget's values based on their input fields
		ob_start();
		include( plugin_dir_path( __FILE__ ) . 'public/views/widget.php' );
		$widget_string .= ob_get_clean();
		$widget_string .= $after_widget;


		$cache[ $args['widget_id'] ] = $widget_string;

		wp_cache_set( 'widget-name-id', $cache, 'widget' );

		print $widget_string;

	} // end widget


	public function flush_widget_cache() {
    		wp_cache_delete( 'widget-name-id', 'widget' );
	}

	/**
	 * Processes the widget's options to be saved.
	 *
	 * @param array new_instance The new instance of values to be generated via the update.
	 * @param array old_instance The previous instance of values before the update.
	 */
	public function update( $new_instance, $old_instance ) {

		$instance = $old_instance;

		// TODO: Here is where you update your widget's old values with the new, incoming values

		return $instance;

	} // end widget

	/**
	 * Generates the administration form for the widget.
	 *
	 * @param array instance The array of keys and values for the widget.
	 */
	public function form( $instance ) {

		// TODO: Define default values for your variables
		$instance = wp_parse_args(
			(array) $instance
		);

		// TODO: Store the values of the widget in their own variable
		// Display the admin form
		include( plugin_dir_path(__FILE__) . 'admin/views/widget.php' );

	} // end form

	/*--------------------------------------------------*/
	/* Public Functions
	/*--------------------------------------------------*/

	/**
	 * Registers and enqueues widget-specific styles.
	 */
	public function register_widget_styles() {

		// TODO: Change 'widget-name' to the name of your plugin
		wp_enqueue_style( 'widget-name-widget-styles', plugins_url( 'widget-name/css/widget.css' ) );

	} // end register_widget_styles

	/**
	 * Registers and enqueues widget-specific scripts.
	 */
	public function register_widget_scripts() {

		// TODO: Change 'widget-name' to the name of your plugin
		wp_enqueue_script( 'widget-name-script', plugins_url( 'widget-name/js/widget.js' ), array('jquery') );

	} // end register_widget_scripts

} // end class

// TODO: Remember to change 'Widget_Name' to match the class name definition
add_action( 'widgets_init', create_function( '', 'register_widget("Widget_Name");' ) );