WordPress自定义元框不会保存

Question

I have the following code which adds a custom meta box to wordpress pages but for some reason it wont save the selected option. Any ideas whats wrong ?

Thanks.

 // Add Header Select Option MetaBox
function alfie_header_select_meta() {
add_meta_box( 'alfie_header_select_meta', __( 'Header Style', 'alfie' ), 'alfie_header_select_meta_callback', 'page', 'side' );
}
add_action( 'add_meta_boxes', 'alfie_header_select_meta' );

function alfie_header_select_meta_callback( $post ) {
$values = get_post_custom( $post->ID );
$selected = isset( $values['alfie_selected_header'] ) ? esc_attr( $values['alfie_selected_header'][0] ) : ”;
wp_nonce_field( 'alfie_header_select_meta_nonce', 'alfie_header_select_meta_nonce' );
?>
  <p>
      <select name="alfie_selected_header" id="alfie_selected_header">
          <option value="alfie-header-default" <?php selected( $selected, 'default' ); ?>>Default</option>
          <option value="alfie-header-style-minimal" <?php selected( $selected, 'minimal' ); ?>>Minimal</option>
          <option value="alfie-header-test" <?php selected( $selected, 'test' ); ?>>Just a test option</option>
      </select>
  </p>
<?php
}

function alfie_meta_save( $post_id ) {
$is_autosave = wp_is_post_autosave( $post_id );
$is_revision = wp_is_post_revision( $post_id );
$is_valid_nonce = ( isset( $_POST[ 'alfie_header_select_meta_nonce' ] ) && wp_verify_nonce( $_POST[ 'alfie_header_select_meta_nonce' ], basename( __FILE__ ) ) ) ? 'true' : 'false';

if ( $is_autosave || $is_revision || !$is_valid_nonce ) {
    return;
}

if( isset( $_POST[ 'alfie_selected_header' ] ) ) {
    update_post_meta( $post_id, 'alfie_selected_header', sanitize_text_field( $_POST[ 'alfie_selected_header' ] ) );
}
}
add_action( 'save_post', 'alfie_meta_save' );

Answer 1

Here is the working debugged code. The post meta was being saved. But it wasnt displaying because of a difference in the string values and how you got the meta. Just use get_post_meta for a single field.

 // Add Header Select Option MetaBox
function alfie_header_select_meta() {
add_meta_box( 'alfie_header_select_meta', __( 'Header Style', 'alfie' ), 'alfie_header_select_meta_callback', 'page', 'side' );
}
add_action( 'add_meta_boxes', 'alfie_header_select_meta' );

function alfie_header_select_meta_callback( $post ) {
$selected = get_post_meta( $post->ID,'alfie_selected_header',true);
wp_nonce_field( 'alfie_header_select_meta_nonce', 'alfie_header_select_meta_nonce' );
?>
  <p>
      <select name="alfie_selected_header" id="alfie_selected_header">
          <option value="alfie-header-default" <?php selected( $selected, 'alfie-header-default' ); ?>>Default</option>
          <option value="alfie-header-style-minimal" <?php selected( $selected, 'alfie-header-style-minimal' ); ?>>Minimal</option>
          <option value="alfie-header-test" <?php selected( $selected, 'alfie-header-test' ); ?>>Just a test option</option>
      </select>
  </p>
<?php
}

function alfie_meta_save( $post_id ) {
$is_autosave = wp_is_post_autosave( $post_id );
$is_revision = wp_is_post_revision( $post_id );
$is_valid_nonce = ( isset( $_POST[ 'alfie_header_select_meta_nonce' ] ) && wp_verify_nonce( $_POST[ 'alfie_header_select_meta_nonce' ], basename( __FILE__ ) ) ) ? 'true' : 'false';

if ( $is_autosave || $is_revision || !$is_valid_nonce ) {
    return;
}

if( isset( $_POST[ 'alfie_selected_header' ] ) ) {
    update_post_meta( $post_id, 'alfie_selected_header', sanitize_text_field( $_POST[ 'alfie_selected_header' ] ) );
}
}
add_action( 'save_post', 'alfie_meta_save' );