cómo guardar un menú desplegable de opciones de selección en un complemento de wordpress

tengo el siguiente código que se toma del códice de WordPress sobre cómo guardar un campo de entrada de texto simple. funciona bien. pero ahora estoy tratando de guardar un menú desplegable de opciones de selección y no puedo entender lo que me estoy perdiendo aquí. parece que se guarda la primera vez que presiono guardar en el menú desplegable, pero cuando trato de editar el valor para seleccionar otra opción y guardarlo, nunca se guarda.

mi otra pregunta es por qué el valor no se imprime en la pantalla cuando ejecuto

testing value saved: <?=esc_attr( get_option('location_one_option') ); ?>

el código del complemento actual está a continuación:

// create custom plugin settings menu
function sidebar_posts_create_menu() {
    //create new top-level menu
    add_menu_page('Sidebar Posts', 'Sidebar Post Settings', 'administrator', __FILE__, 'sidebar_posts_settings_page' );

    //call register settings function
    add_action( 'admin_init', 'register_sidebar_posts_settings' );
}
add_action('admin_menu', 'sidebar_posts_create_menu');

//register our settings
function register_sidebar_posts_settings() {
    //register our settings
    register_setting( 'sidebar-posts-settings-group', 'location_one_option' );
    register_setting( 'sidebar-posts-settings-group', 'new_option_name' );
}

//register settings page view
function sidebar_posts_settings_page() {
    ?>
    <div class="wrap">
        <h1>Sidebar Posts Settings</h1>
        <p>Select up to six posts to show in six different locations on the sidebar. Have fun!</p>

        <form method="post" action="options.php">
            <?php settings_fields( 'sidebar-posts-settings-group' ); ?>
            <?php do_settings_sections( 'sidebar-posts-settings-group' ); ?>
            <table class="form-table">
                <tr valign="top">
                    <th scope="row">New Option Name</th>
                    <td><input type="text" name="new_option_name" value="<?php echo esc_attr( get_option('new_option_name') ); ?>" /></td>
                </tr>
<!--the above simple text field saves the data perfectly-->

                <?php
                $your_query = new WP_Query( 'posts_per_page=-1' ); ?>
                                <label>Location One Post</label><br />
            <select name="location_one_option">
                <option value="" selected="selected">Select a post</option>
                <?php while ( $your_query->have_posts() ) : $your_query->the_post(); ?>
                <option value="<?=esc_attr( get_option('location_one_option') ); ?>" <?php selected( get_option('location_one_option'), get_option('location_one_option') ); ?>>
                    <?=the_title(); ?>
                </option>
                <? endwhile; ?>
            </select>
            <? wp_reset_postdata(); ?><br /><br />
            testing value saved: <?=esc_attr( get_option('location_one_option') ); ?>

            </table>
            <?php submit_button(); ?>
        </form>
    </div>
<?php }

Use esta función, este es solo un ejemplo para guardar un menú desplegable de opciones seleccionadas en un complemento de wordpress, puede usarlo según sus necesidades.

Ejemplo 1

class DropdownOptionSetting {
    private $dropdown_option_setting_options;

    public function __construct() {
        add_action( 'admin_menu', array( $this, 'dropdown_option_setting_add_plugin_page' ) );
        add_action( 'admin_init', array( $this, 'dropdown_option_setting_page_init' ) );
    }

    public function dropdown_option_setting_add_plugin_page() {
        add_options_page(
            'Dropdown Option Setting', // page_title
            'Dropdown Option Setting', // menu_title
            'manage_options', // capability
            'dropdown-option-setting', // menu_slug
            array( $this, 'dropdown_option_setting_create_admin_page' ) // function
        );
    }

    public function dropdown_option_setting_create_admin_page() {
        $this->dropdown_option_setting_options = get_option( 'dropdown_option_setting_option_name' ); ?>

        <div class="wrap">
            <h2>Dropdown Option Setting</h2>
            <p></p>
            <?php settings_errors(); ?>

            <form method="post" action="options.php">
                <?php
                    settings_fields( 'dropdown_option_setting_option_group' );
                    do_settings_sections( 'dropdown-option-setting-admin' );
                    submit_button();
                ?>
            </form>
        </div>
    <?php }

    public function dropdown_option_setting_page_init() {
        register_setting(
            'dropdown_option_setting_option_group', // option_group
            'dropdown_option_setting_option_name', // option_name
            array( $this, 'dropdown_option_setting_sanitize' ) // sanitize_callback
        );

        add_settings_section(
            'dropdown_option_setting_setting_section', // id
            'Settings', // title
            array( $this, 'dropdown_option_setting_section_info' ), // callback
            'dropdown-option-setting-admin' // page
        );

        add_settings_field(
            'dropdown_option_0', // id
            'Dropdown Option', // title
            array( $this, 'dropdown_option_0_callback' ), // callback
            'dropdown-option-setting-admin', // page
            'dropdown_option_setting_setting_section' // section
        );
    }

    public function dropdown_option_setting_sanitize($input) {
        $sanitary_values = array();
        if ( isset( $input['dropdown_option_0'] ) ) {
            $sanitary_values['dropdown_option_0'] = $input['dropdown_option_0'];
        }

        return $sanitary_values;
    }

    public function dropdown_option_setting_section_info() {

    }

    public function dropdown_option_0_callback() {
        ?> <select name="dropdown_option_setting_option_name[dropdown_option_0]" id="dropdown_option_0">
            <?php $selected = (isset( $this->dropdown_option_setting_options['dropdown_option_0'] ) && $this->dropdown_option_setting_options['dropdown_option_0'] === 'option-one') ? 'selected' : '' ; ?>
            <option value="option-one" <?php echo $selected; ?>>Option One</option>
            <?php $selected = (isset( $this->dropdown_option_setting_options['dropdown_option_0'] ) && $this->dropdown_option_setting_options['dropdown_option_0'] === 'option-two') ? 'selected' : '' ; ?>
            <option value="option-two" <?php echo $selected; ?>>Option Two</option>
            <?php $selected = (isset( $this->dropdown_option_setting_options['dropdown_option_0'] ) && $this->dropdown_option_setting_options['dropdown_option_0'] === 'option-three') ? 'selected' : '' ; ?>
            <option value="option-three" <?php echo $selected; ?>>Option Three</option>
        </select> <?php
    }

}
if ( is_admin() )
    $dropdown_option_setting = new DropdownOptionSetting();

Recuperar este valor

$dropdown_option = get_option( 'dropdown_option_setting_option_name' ); // Array
$dropdown_value =  $dropdown_option ['dropdown_option_0']; // Option value

Si necesita una manera simple de hacer esto

Ejemplo 2

add_action( 'admin_init', 'Dropdown_settings_init' );

function Dropdown_settings_init(  ) { 
    register_setting( 'pluginPage', 'dropdown_settings' );
    add_settings_section(
        'Dropdown_pluginPage_section', 
        __( 'Your section description', 'dropdown' ), 
        'Dropdown_settings_section_callback', 
        'pluginPage'
    );

    add_settings_field( 
        'select_field_0', 
        __( 'Settings field description', 'dropdown' ), 
        'Dropdown_select_field_render', 
        'pluginPage', 
        'Dropdown_pluginPage_section' 
    );
}


function Dropdown_select_field_render(  ) { 
    $options = get_option( 'dropdown_settings' );
    ?>
    <select name="dropdown_settings[select_field_0]">
        <option value="1" <?php selected( $options['select_field_0'], 1 ); ?>>Option 1</option>
        <option value="2" <?php selected( $options['select_field_0'], 2 ); ?>>Option 2</option>
        <option value="3" <?php selected( $options['select_field_0'], 3 ); ?>>Option 3</option>
        <option value="4" <?php selected( $options['select_field_0'], 4 ); ?>>Option 4</option>
    </select>
<?php
}


function Dropdown_settings_section_callback(  ) { 
    echo __( 'This section description', 'dropdown' );
}


function Dropdown_options_page(  ) { 
    ?>
    <form action='options.php' method='post'>
        <h2>Dropdown</h2>
        <?php
        settings_fields( 'pluginPage' );
        do_settings_sections( 'pluginPage' );
        submit_button();
        ?>
    </form>
    <?php
}
?>