WP - Latest post from category

widget-barletta-latest-post.php

<?php
/**
 * Custom Latest Post By Category Widget
 *
 * @package Barletta
 */
class barletta_latest_post extends WP_Widget {

	public function __construct(){
		$widget_ops = array('classname' => 'barletta-latest-post','description' => esc_html__( "Barletta Latest Post Widget", 'barletta') );
		parent::__construct('barletta_latest_post', esc_html__('Barletta Latest Post Widget','barletta'), $widget_ops);
	}

	public function widget( $args, $instance ) {
		$title = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );
		$category = ! empty( $instance['category'] ) ? $instance['category'] : false;

		echo $args['before_widget'];
		if ( ! empty( $title ) ) {
			echo $args['before_title'] . $title . $args['after_title'];
		}

		$query_args = array( 
						'cat' 				=> $category, 
						'orderby' 			=> 'date', 
						'order' 			=> 'DESC', 
						'post_status' 		=> 'publish',
						'has_password' 		=> false,
						'posts_per_page' 	=> 1
					);
			
		$posts = new WP_Query( $query_args );
		if($posts->have_posts()){
			while($posts->have_posts()){
				$posts->the_post(); ?>
				<article class="list-post" style="border-bottom: none;margin-bottom: 0px;padding-bottom: 0px;">
					<div class="list-post-body" style="padding: 0px;">
						<h2 class="entry-title"><a href="<?php the_permalink(); ?>" rel="bookmark"><?php the_title(); ?></a></h2>
						<div class="post-meta">
							<span>Přidáno dne: <?php echo get_the_date(); ?></span>
						</div>
						<?php the_content()?>
						<div class="read-more"><a href="<?php the_permalink(); ?>"><?php esc_html_e( 'Continue Reading', 'barletta' ); ?></a></div>
					</div>
				</article>
			<?php }
			wp_reset_query();
		}	
		echo $args['after_widget'];
	}

	public function update( $new_instance, $old_instance ) {
		$instance = $old_instance;
		$instance['title'] = sanitize_text_field( $new_instance['title'] );
		$instance['category'] = sanitize_text_field( $new_instance['category'] );
		return $instance;
	}

	public function form( $instance ) {
		$instance = wp_parse_args( (array) $instance, array( 'title' => '', 'category' => '' ) );
		$title = sanitize_text_field( $instance['title'] );
		$category = sanitize_text_field( $instance['category'] );
		?>
		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($title); ?>" /></p>

		<p><label for="<?php echo $this->get_field_id('category'); ?>"><?php _e('Category:'); ?></label> 
	        <select class='widefat' id="<?php echo $this->get_field_id('category'); ?>" name="<?php echo $this->get_field_name('category'); ?>" >
	        <?php
				$cats = get_categories( array( 'hide_empty' => 0 ) );
				foreach ( $cats as $cat ) {
					echo '<option value="' . $cat->term_id . '"'
						. selected( $category, $cat->term_id, false )
						. '>'. esc_html( $cat->name ) . '</option>';
				}
			?>
	        </select>
    	</p>
		<?php
	}
}