single-widget.php

<?php
/**
 * Plugin Name: Old-Style Single Widget with Wide Control
 * Description: For testing purposes.
 * Author: Weston Ruter, XWP
 * Author URI: https://weston.ruter.net/
 */

add_action( 'widgets_init', 'single_widget_register' );

/**
 * Register single widget.
 */
function single_widget_register() {
	$id = 'single';
	$name = __( 'Wide Single', 'single-widget' );
	$widget_ops = array(
		'classname' => 'widget_single',
		'description' => __( 'Old single wide widget for testing purposes.', 'single-widget' ),
	);
	$control_ops = array(
		'width' => 500,
		'height' => 100,
		'id_base' => $id,
	);
	wp_register_sidebar_widget( $id, $name, 'single_widget_display', $widget_ops, array() );
	wp_register_widget_control( $id, $name, 'single_widget_update_form', $control_ops, array() );
}

/**
 * Display widget.
 *
 * @see WP_Widget::widget()
 *
 * @param array $args Widget args.
 */
function single_widget_display( $args ) {
	$options = array_merge(
		array( 'title' => '' ),
		get_option( 'widget_single', array() )
	);
	$title = apply_filters( 'widget_title', $options['title'] );
	echo $args['before_widget'];
	if ( ! empty( $title ) ) {
		echo $args['before_title'];
		echo $title;
		echo $args['after_title'];
	}
	?>
	<div id="single_wrap">
		<?php _e( 'I am an old single wide widget which should be deprecated in favor of <code>WP_Widget</code>!', 'single-widget' ); ?>
	</div>
	<?php
	echo $args['after_widget'];
}

/**
 * Show the widget form and handle updates to the widget.
 *
 * @see WP_Widget::form()
 * @see WP_Widget::update()
 */
function single_widget_update_form() {
	global $wp_registered_widget_controls;
	$instance = array_merge(
		array( 'title' => '' ),
		get_option( 'widget_single', array() )
	);
	if ( isset( $_POST['single-submit'] ) ) {
		$instance['title'] = sanitize_text_field( wp_unslash( $_POST['single-title'] ) );
		update_option( 'widget_single', $instance );
	}
	?>
	<p>
		<label for="single-title">
			<?php _e( 'Title:' ); ?>
			<input class="widefat" id="single-title" name="single-title" type="text" value="<?php echo esc_attr( $instance['title'] ); ?>" />
		</label>
	</p>
	<p>
		<em>
			<?php
			/* translators: placeholder is width of widget */
			echo sprintf( __( 'I am an old-style single widget with a %spx wide widget control.', 'single-widget' ), $wp_registered_widget_controls['single']['width'] );
			?>
		</em>
	</p>
	<input type="hidden" id="single-submit" name="single-submit" value="1" />
	<?php
}