I have recently written a widget that
-
Gets all the terms from the build in taxonomy
categoryand adds them in dropdown in the widget -
Stores the selected category and uses that category in a custom
WP_Queryto get and display posts from the selected category
You can look through it and adjust as needed: (Required PHP 5.4+)
(EDIT: Thanks @birgire for spotting the use of array() and [] notation. Corrected to use only [])
<?php
/**
* Category_Posts widget class
*
* Displays posts from a selected category
*
* @since 1.0.0
*/
class Category_Posts extends WP_Widget
{
public function __construct()
{
parent::__construct(
'widget_category_posts',
_x( 'Category Posts Widget', 'Category Posts Widget' ),
[ 'description' => __( 'Display a list of posts from a selected category.' ) ]
);
$this->alt_option_name="widget_category_posts";
add_action( 'save_post', [$this, 'flush_widget_cache'] );
add_action( 'deleted_post', [$this, 'flush_widget_cache'] );
add_action( 'switch_theme', [$this, 'flush_widget_cache'] );
}
public function widget( $args, $instance )
{
$cache = [];
if ( ! $this->is_preview() ) {
$cache = wp_cache_get( 'widget_cat_posts', 'widget' );
}
if ( ! is_array( $cache ) ) {
$cache = [];
}
if ( ! isset( $args['widget_id'] ) ) {
$args['widget_id'] = $this->id;
}
if ( isset( $cache[ $args['widget_id'] ] ) ) {
echo $cache[ $args['widget_id'] ];
return;
}
ob_start();
$title = ( ! empty( $instance['title'] ) ) ? $instance['title'] : __( 'Category Posts' );
/** This filter is documented in wp-includes/default-widgets.php */
$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );
$number = ( ! empty( $instance['number'] ) ) ? absint( $instance['number'] ) : 5;
if ( ! $number ) {
$number = 5;
}
$cat_id = $instance['cat_id'];
$random = $instance['rand'] ? true : false;
$excerpt = $instance['excerpt'] ? true : false;
$thumbnail = $instance['thumbnail'] ? true : false;
/**
* Filter the arguments for the Category Posts widget.
*
* @since 1.0.0
*
* @see WP_Query::get_posts()
*
* @param array $args An array of arguments used to retrieve the category posts.
*/
if( true === $random ) {
$query_args = [
'posts_per_page' => $number,
'cat' => $cat_id,
'orderby' => 'rand'
];
}else{
$query_args = [
'posts_per_page' => $number,
'cat' => $cat_id,
];
}
$q = new WP_Query( apply_filters( 'category_posts_args', $query_args ) );
if( $q->have_posts() ) {
echo $args['before_widget'];
if ( $title ) {
echo $args['before_title'] . $title . $args['after_title'];
}
while( $q->have_posts() ) {
$q->the_post(); ?>
<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
<header class="entry-header">
<?php the_title( '<h1 class="entry-title"><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">', '</a></h1>' ); ?>
</header><!-- .entry-header -->
<?php
if ( has_post_thumbnail() && true === $thumbnail ) { ?>
<div class="post-thumbnail">
<?php the_post_thumbnail(); ?>
</div><!--/.post-thumbnail-->
<?php
}
if( true === $excerpt ) { ?>
<div class="entry-summary">
<?php the_excerpt(); ?>
</div><!-- .entry-summary -->
<?php } ?>
</article><!-- #post-## -->
<?php
}
wp_reset_postdata();
}
echo $args['after_widget'];
if ( ! $this->is_preview() ) {
$cache[ $args['widget_id'] ] = ob_get_flush();
wp_cache_set( 'widget_cat_posts', $cache, 'widget' );
} else {
ob_end_flush();
}
}
public function update( $new_instance, $old_instance )
{
$instance = $old_instance;
$instance['title'] = strip_tags( $new_instance['title'] );
$instance['number'] = (int) $new_instance['number'];
$instance['cat_id'] = (int) $new_instance['cat_id'];
$instance['rand'] = $new_instance['rand'];
$instance['excerpt'] = $new_instance['excerpt'];
$instance['thumbnail'] = $new_instance['thumbnail'];
$this->flush_widget_cache();
$alloptions = wp_cache_get( 'alloptions', 'options' );
if ( isset($alloptions['widget_category_posts']) )
delete_option('widget_category_posts');
return $instance;
}
public function flush_widget_cache()
{
wp_cache_delete('widget_cat_posts', 'widget');
}
public function form( $instance )
{
$title = isset( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
$number = isset( $instance['number'] ) ? absint( $instance['number'] ) : 5;
$cat_id = isset( $instance['cat_id'] ) ? absint( $instance['cat_id'] ) : 1;
$random = isset( $instance['rand'] ) ? $instance['rand'] : false;
$excerpt = isset( $instance['excerpt'] ) ? $instance['excerpt'] : false;
$thumbnail = isset( $instance['thumbnail'] ) ? $instance['thumbnail'] : false;
?>
<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 $title; ?>" />
</p>
<p>
<label for="<?php echo $this->get_field_id( 'number' ); ?>"><?php _e( 'Number of posts to show:' ); ?></label>
<input id="<?php echo $this->get_field_id( 'number' ); ?>" name="<?php echo $this->get_field_name( 'number' ); ?>" type="text" value="<?php echo $number; ?>" size="3" />
</p>
<p>
<label for="<?php echo $this->get_field_id('cat_id'); ?>"><?php _e( 'Category Name:' )?></label>
<select id="<?php echo $this->get_field_id('cat_id'); ?>" name="<?php echo $this->get_field_name('cat_id'); ?>">
<?php
$this->categories = get_categories();
foreach ( $this->categories as $cat ) {
$selected = ( $cat->term_id == esc_attr( $cat_id ) ) ? ' selected = "selected" ' : '';
$option = '<option '.$selected .'value="' . $cat->term_id;
$option = $option .'">';
$option = $option .$cat->name;
$option = $option .'</option>';
echo $option;
}
?>
</select>
</p>
<p>
<label for="<?php echo $this->get_field_id('rand'); ?>"><?php _e( 'Show random posts' ); ?></label>
<?php $checked = ( $random ) ? ' checked=\"checked\" ' : ''; ?>
<input type="checkbox" id="<?php echo $this->get_field_id( 'rand' ); ?>" name="<?php echo $this->get_field_name( 'rand' ); ?>" value="true" <?php echo $checked; ?> />
</p>
<p>
<label for="<?php echo $this->get_field_id('excerpt'); ?>"><?php _e( 'Show excerpt. If unchecked, only the title of the post will be displayed' ); ?></label>
<?php $checked = ( $excerpt ) ? ' checked=\"checked\" ' : ''; ?>
<input type="checkbox" id="<?php echo $this->get_field_id( 'excerpt' ); ?>" name="<?php echo $this->get_field_name( 'excerpt' ); ?>" value="true" <?php echo $checked; ?> />
</p>
<p>
<label for="<?php echo $this->get_field_id('thumbnail'); ?>"><?php _e( 'Hide post thumbnail' ); ?></label>
<?php $checked = ( $thumbnail ) ? ' checked=\"checked\" ' : ''; ?>
<input type="checkbox" id="<?php echo $this->get_field_id( 'thumbnail' ); ?>" name="<?php echo $this->get_field_name( 'thumbnail' ); ?>" value="true" <?php echo $checked; ?> />
</p>
<?php
}
}
add_action( 'widgets_init', function ()
{
register_widget( 'Category_Posts' );
});