How to store widget fields data as an array?

2 comments

1. You have to collect multiple fields under the same name like this …

   name="collect[1]"
   name="collect[2]"
   

   … and adjust your widget logic to this.

   Here is a very simple demo widget:

   <?php  # -*- coding: utf-8 -*-
   /* Plugin Name: Store Options as array */
   
   add_action( 'widgets_init', array ( 'T5_Array_Options_Widget', 'register' ) );
   
   class T5_Array_Options_Widget extends WP_Widget
   {
       /**
        * Constructor.
        */
       public function __construct()
       {
           parent::__construct( strtolower( __CLASS__ ), 'Array Demo' );
       }
   
       /**
        * Echo the settings update form
        *
        * @param array $instance Current settings
        */
       public function form( $instance )
       {
           $title = isset ( $instance['title'] ) ? $instance['title'] : '';
           $title = esc_attr( $title );
   
           printf(
               '<p><label for="%1$s">%2$s</label><br />
               <input type="text" name="%3$s" id="%1$s" value="%4$s" class="widefat"></p>',
               $this->get_field_id( 'title' ),
               'Title',
               $this->get_field_name( 'title' ),
               $title
           );
   
           $fields = isset ( $instance['fields'] ) ? $instance['fields'] : array();
           $field_num = count( $fields );
           $fields[ $field_num + 1 ] = '';
           $fields_html = array();
           $fields_counter = 0;
   
           foreach ( $fields as $name => $value )
           {
               $fields_html[] = sprintf(
                   '<input type="text" name="%1$s[%2$s]" value="%3$s" class="widefat">',
                   $this->get_field_name( 'fields' ),
                   $fields_counter,
                   esc_attr( $value )
               );
               $fields_counter += 1;
           }
   
           print 'Fields<br />' . join( '<br />', $fields_html );
       }
   
       /**
        * Renders the output.
        *
        * @see WP_Widget::widget()
        */
       public function widget( $args, $instance )
       {
           print $args['before_widget']
           . $args['before_title']
           . apply_filters( 'widget_title', $instance['title'] )
           . $args['after_title']
           . join( '<br />', $instance['fields'] )
           . $args['after_widget'];
       }
   
       /**
        * Prepares the content. Not.
        *
        * @param  array $new_instance New content
        * @param  array $old_instance Old content
        * @return array New content
        */
       public function update( $new_instance, $old_instance )
       {
           $instance          = $old_instance;
           $instance['title'] = esc_html( $new_instance['title'] );
   
           $instance['fields'] = array();
   
           if ( isset ( $new_instance['fields'] ) )
           {
               foreach ( $new_instance['fields'] as $value )
               {
                   if ( '' !== trim( $value ) )
                       $instance['fields'][] = $value;
               }
           }
   
           return $instance;
       }
   
       /**
        * Tell WP we want to use this widget.
        *
        * @wp-hook widgets_init
        * @return void
        */
       public static function register()
       {
           register_widget( __CLASS__ );
       }
   }
   

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2. The above answer is good if you need the fields to be numbered. In my case, I didn’t. I have a widget with options that allow the user to select any number of categories to be used within the widget.

   

   Here’s my widget form. — Three important things here

   1. Make sure to default the value to an empty array() if the widget’s value is not set
   2. In the form <label> name attribute, notice that I attach a [] at the end. This tells PHP that I’m submitting an array of values for this key
   3. Wrap the checkbox in the label as <label><input type="checkbox" ...></label>. — Each of our checkboxes will not have a unique id attribute, so the <label> for attribute will not work. We could generate unique IDs, but that’s a hassle. If you just wrap the label around the input, the label get associated properly without the hassle of connecting the for+id

   Now the code

   public function form($instance) {
     $title = isset($instance['title']) ? $instance['title'] : '';
     $categories = isset($instance['categories']) ? $instance['categories'] : array();
     ?>
   
     <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') ?>"
              value="<?php echo $title ?>" />
     </p>
   
     <p>Categories</p>
     <ul>
     <?php foreach (get_categories() as $category): ?>
       <li>
         <label>
           <input type="checkbox"
                class="checkbox"
                name="<?php echo $this->get_field_name('categories') ?>[]"
                value="<?php echo $category->cat_ID ?>"
                <?php checked(in_array($category->cat_ID, $categories)) ?> />
           <?php echo $category->name ?>
         </label>
       </li>
     <?php endforeach ?>
     </ul>
     <?php
   }
   

   And here’s my update function

   I’m interested in saving the Category IDs in an array, which are numbers, so I use array_map with intval to ensure that all submitted datum are valid integers. Additionally, I use array_filter to remove any invalid submissions.

   // @param array $a - the new instance options
   // @param arram $b - the old instance options
   public function update($a, $b) {
     return array(
       'title'      => isset($a['title']) ? strip_tags($a['title']) : $b['title'],
       'categories' => isset($a['categories']) ? array_filter(array_map(function($id) { return intval($id); }, (array) $a['categories'])) : (array) $b['title']
     );
   }
   

   It’s particularly challenging to describe this WordPress stuff. If you have any questions, I’ll be happy to elaborate.

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