Reply To: Unique value across all posts/pages

• nicmare

• October 29, 2015 at 4:16 am

okay. that was easy! here we go. simply adjust it to your needs:
1. create a new entry in wp_options: “is_winner”
2. insert that code to your functions.php:

// register the meta box
add_action( 'add_meta_boxes', 'my_custom_field_checkboxes' );
function my_custom_field_checkboxes() {
    add_meta_box(
        'winner_box',          // this is HTML id of the box on edit screen
        'Winner',    // title of the box
        'my_customfield_box_content',   // function to be called to display the checkboxes, see the function below
        'product',        // on which edit screen the box should appear
        'side',      // part of page where the box should appear
        'default'      // priority of the box
    );
}

// display the metabox
function my_customfield_box_content( $post_id ) {
    wp_nonce_field( 'wp_nonce_check', 'myplugin_nonce' );
    echo '<label><input type="checkbox" name="is_winner" value="1" /> Winner';
    if(get_the_id() == get_option("is_winner")) echo " (currently selected)";
    echo "</label>";
}

// save data from checkboxes
add_action( 'save_post', 'my_custom_field_data' );
function my_custom_field_data() {
    // check if this isn't an auto save
    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
        return;

    // security check
    if ( ! isset( $_POST['myplugin_nonce'] ) || !wp_verify_nonce( $_POST['myplugin_nonce'], 'wp_nonce_check' ) )
        return;

    if ( isset( $_POST['is_winner'] ) )
    	update_option("is_winner", get_the_id());
    else
        return;
}

now in every post is a meta box along with ACF fields. when you check that meta box, the id is saved to the field in wp_options. this way, you save a lot of performance because there is no wp_query and you do not need to alter all posts!!

Screenshot-2....png