unable to save post meta on single field with multiple selects

Question

I set up two select boxes in one meta field by putting two arrays inside the 'options' array of my callback. The HTML is outputting fine, but the meta is not being saved to the database...

Here is a pic of the meta box setup (for whatever random reason that make me think it would be helpful):

...aaaaaaaaaaaaaaaaaaand here's my code:

add_action( 'add_meta_boxes', 'event_infobox_add' );                                                        
add_action( 'save_post', 'event_infobox_save' );
function event_infobox_add() {
add_meta_box( 
'event_infobox', // $id 
'Event Date, Time, and Venue Info', // $title 
'event_infobox_call', // $callback
'events', // $page
'normal', // $context 
'high' // $priority   
);
}

// Time options for dropdowns in the HTML
$times = array(  'hour00' => '12AM' ,'hour01' => '1AM' ,'hour02' => '2AM' ,'hour03' => '3AM' ,'hour04' => '4AM' ,'hour05' => '5AM' ,'hour06' => '6AM' ,'hour07' => '7AM' ,'hour08' => '8AM' ,'hour09' => '9AM' ,'hour10' => '10AM' ,'hour11' => '11AM' ,'hour12' => '12PM' ,'hour13' => '1PM' ,'hour14' => '2PM' ,'hour15' => '3PM' ,'hour16' => '4PM' ,'hour17' => '5PM' ,'hour18' => '6PM' ,'hour19' => '7PM' ,'hour20' => '8PM' ,'hour21' => '9PM' ,'hour22' => '10PM' ,'hour23' => '11PM' );

// Meta Box fields HTML
$event_infobox_fields = array(
array(
     'label' => 'Event Time Frame'
    ,'desc' => 'Enter time frame of the event here'
    ,'id' => 'event_timeframe'  //values stored with this key
    ,'class' => ''
    ,'type' => 'select'
    ,'options' => array(
        'timestart' => $times,
        'timeend' => $times
    )
)
);

function event_infobox_call( $post ) {
global $event_infobox_fields, $post;  
// Use nonce for verification  
wp_nonce_field( plugin_basename( __FILE__ ), 'event_infobox_nonce' );
echo '<input type="hidden" name="event_infobox_box_nonce" value="'.wp_create_nonce(basename(__FILE__)).'" />';  

// Loop it up
echo '<table class="form-table">';

foreach ($event_infobox_fields as $field) {  
    $meta = get_post_meta($post->ID, $field['id'], true); 
    echo '<tr>
    <th>
        <label for="'.$field['id'].'">'.$field['label'].'</label>
        <span class="meta-description">'.$field['desc'].'</span>
    </th>
    <td>';
    switch($field['type']) {

        case 'select':

        // Event Timeframe Select Dropdowns
        if ( $field['id'] == 'event_timeframe') {
            foreach ($field['options'] as $key => $value ){
                echo $meta;
                $keyhead = str_replace('time','',$key);
                echo '<span>'.$keyhead.'</span>
                            <select style="width:200px; display:block;" name="'.$key.'" id="'.$key.'">';
                $total = count($field['options'][$key])-1;
                for ($i=0; $i<=$total; $i++){
                    if($i<10) {
                        $i="0$i";
                    }
                    echo '<option style="width:200px; display:block;" value="'.$field['options'][$key]['hour'.$i].'"', $meta == $field['options'][$key]['hour'.$i] ? 'selected="selected"' : '','>'.$field['options'][$key]['hour'.$i].'</option>';
                }
                echo '</select>';
            }
        }

        ////////////

        break;  

    } //end switch  
echo '</td></tr>';  
} // end foreach

echo '</table>'; // end table  
}

// $ave $ave $ave
function event_infobox_save( $post_id ) { 
global $event_infobox_fields;  

// verify nonce  
if (!wp_verify_nonce($_POST['event_infobox_box_nonce'], basename(__FILE__)))  
        return $post_id;  
// check autosave  
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)  
        return $post_id;  
// check permissions  
if ('page' == $_POST['post_type']) {  
        if (!current_user_can('edit_page', $post_id))  
                return $post_id;  
        } elseif (!current_user_can('edit_post', $post_id)) {  
                return $post_id;  
}    
// loop through fields and save the data  
foreach ($event_infobox_fields as $field) {  
    $old = get_post_meta($post_id, $field['id'], true);
    $new = $_POST[$field['id']]; 

    if ($new && $new != $old) {  
            update_post_meta($post_id, $field['id'], $new); 
    }

    elseif ('' == $new && $old) {  
            delete_post_meta($post_id, $field['id'], $old);  
    }  
} // end foreach  
}

Answer 1

In your save code, the value of $field['id'] is event_timeframe, which does not exist in $_POST, so your options will never save.

You need to dig down into your options array to get to timestart and timeend:

// loop through fields and save the data  
    foreach ( $event_infobox_fields as $field ) {
        foreach ( $field['options'] as $option_key => $option_value ) {
            $old = get_post_meta( $post_id, $option_key, true );
            $new = $_POST[$option_key];
            if ( $new && $new != $old ) {
                update_post_meta( $post_id, $option_key, $new );
            } elseif ( '' == $new && $old ) {
                delete_post_meta( $post_id, $option_key, $old );
            }
        } // end foreach  
    }

Bear in mind that you will also have to update the meta used in your dropdown code in order to pre-populate those.