Add input field to ‘Pages > Edit Page’ through functions.php

3 comments

1. functions.php

   // Add custom Slider ID field to 'Edit Page'
   add_action( 'add_meta_boxes', 'cd_meta_box_add' );
   function cd_meta_box_add() {
       add_meta_box( 'my-meta-box-id', 'Slider', 'cd_meta_box_cb', 'page', 'normal', 'high' );
   }
   function cd_meta_box_cb( $post ) {
       $values = get_post_custom( $post->ID );
       $text = isset( $values['my_meta_box_text'] ) ? esc_attr( $values['my_meta_box_text'][0] ) : '';
       wp_nonce_field( 'my_meta_box_nonce', 'meta_box_nonce' );
       ?>
       <p>
           <label for="my_meta_box_text">Add a slider ID</label>
           <input type="text" name="my_meta_box_text" id="my_meta_box_text" value="<?php echo $text; ?>" />
       </p>
       <?php   
   }
   add_action( 'save_post', 'cd_meta_box_save' );
   function cd_meta_box_save( $post_id ) {
       // Bail if we're doing an auto save
       if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
       // if our nonce isn't there, or we can't verify it, bail
       if( !isset( $_POST['meta_box_nonce'] ) || !wp_verify_nonce( $_POST['meta_box_nonce'], 'my_meta_box_nonce' ) ) return;
       // if our current user can't edit this post, bail
       if( !current_user_can( 'edit_post', $post_id ) ) return;
       // now we can actually save the data
       $allowed = array( 
           'a' => array( // on allow a tags
               'href' => array() // and those anchords can only have href attribute
           )
       );
       // Probably a good idea to make sure your data is set
       if( isset( $_POST['my_meta_box_text'] ) )
           update_post_meta( $post_id, 'my_meta_box_text', wp_kses( $_POST['my_meta_box_text'], $allowed ) );
   }
   

   Page.php

   <?php echo do_shortcode( '[cycloneslider id="' . get_post_meta(get_the_ID(), 'my_meta_box_text', true) . '"]'); ?>
   

2. First of all, you should use custom fields, if you want to assign some additional value to post/page and not globally for site.

   Then you should use add_meta_box function to register your custom meta box, which will allow to edit these custom fields easily.

   Here is a sample code:

   // register your custom meta box
   function my_slider_properties_meta_box() {
       add_meta_box('my_slider_properties', 'Link Format Title URL', 'my_slider_properties', 'page', 'side', 'default');
   }
   add_action('add_meta_boxes', 'my_slider_properties_meta_box');
   
   
   // echo your custom meta box
   function my_slider_properties() {
       global $post; 
   
       $my_slider_id = get_post_meta($post->ID, '_my_slider_id', true);
   
       echo '<p>My slider id</p>';
       echo '<input type="text" name="_my_slider_id" value="' . esc_attr($my_slider_id)  . '" size="40" />';
   }
   
   
   // process your custom meta box while saving
   function my_slider_properties_save_meta($post_id, $post) {
       if ( !current_user_can( 'edit_post', $post->ID ))
           return $post->ID;
   
       $metas['_my_slider_id'] = $_POST['_my_slider_id'];
   
       foreach ($metas as $key => $value) {
           update_post_meta($post->ID, $key, $value);
       }
   }
   add_action('save_post', 'my_slider_properties', 1, 2);
   

   It’s only basic example how to do this. You should take care of security (use nonces) and other things, I guess. But the idea should be clear now.

   (6 chars)

3. If you want to save slider id for the page specific for all pages then you should go with using post meta boxes instead of wp options.

   To get value from post meta use get_post_meta() function in place of get_option() function.

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