add_meta_box
/**
* Calls the class on the post edit screen.
*/
function call_someClass() {
new someClass();
}
if ( is_admin() ) {
add_action( 'load-post.php', 'call_someClass' );
add_action( 'load-post-new.php', 'call_someClass' );
}
/**
* The Class.
*/
class someClass {
/**
* Hook into the appropriate actions when the class is constructed.
*/
public function __construct() {
add_action( 'add_meta_boxes', array( $this, 'add_meta_box' ) );
add_action( 'save_post', array( $this, 'save' ) );
}
/**
* Adds the meta box container.
*/
public function add_meta_box( $post_type ) {
// Limit meta box to certain post types.
$post_types = array( 'post', 'page' );
if ( in_array( $post_type, $post_types ) ) {
add_meta_box(
'some_meta_box_name',
__( 'Some Meta Box Headline', 'textdomain' ),
array( $this, 'render_meta_box_content' ),
$post_type,
'advanced',
'high'
);
}
}
/**
* Save the meta when the post is saved.
*
* @param int $post_id The ID of the post being saved.
*/
public function save( $post_id ) {
/*
* We need to verify this came from the our screen and with proper authorization,
* because save_post can be triggered at other times.
*/
// Check if our nonce is set.
if ( ! isset( $_POST['myplugin_inner_custom_box_nonce'] ) ) {
return $post_id;
}
$nonce = $_POST['myplugin_inner_custom_box_nonce'];
// Verify that the nonce is valid.
if ( ! wp_verify_nonce( $nonce, 'myplugin_inner_custom_box' ) ) {
return $post_id;
}
/*
* If this is an autosave, our form has not been submitted,
* so we don't want to do anything.
*/
if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
return $post_id;
}
// Check the user's permissions.
if ( 'page' == $_POST['post_type'] ) {
if ( ! current_user_can( 'edit_page', $post_id ) ) {
return $post_id;
}
} else {
if ( ! current_user_can( 'edit_post', $post_id ) ) {
return $post_id;
}
}
/* OK, it's safe for us to save the data now. */
// Sanitize the user input.
$mydata = sanitize_text_field( $_POST['myplugin_new_field'] );
// Update the meta field.
update_post_meta( $post_id, '_my_meta_value_key', $mydata );
}
/**
* Render Meta Box content.
*
* @param WP_Post $post The post object.
*/
public function render_meta_box_content( $post ) {
// Add an nonce field so we can check for it later.
wp_nonce_field( 'myplugin_inner_custom_box', 'myplugin_inner_custom_box_nonce' );
// Use get_post_meta to retrieve an existing value from the database.
$value = get_post_meta( $post->ID, '_my_meta_value_key', true );
// Display the form, using the current value.
?>
<label for="myplugin_new_field">
<?php _e( 'Description for this field', 'textdomain' ); ?>
</label>
<input type="text" id="myplugin_new_field" name="myplugin_new_field" value="<?php echo esc_attr( $value ); ?>" size="25" />
<?php
}
}
