Settings API based on User ID

uid-settings.php

<?php
/*
  Plugin Name: Settings API based on User ID
 */

class MySettingsPage2
{
    /**
     * Holds the values to be used in the fields callbacks
     */
    private $options;
    private $prefix;

    /**
     * Start up
     */
    public function __construct()
    {
        add_action( 'admin_menu', array( $this, 'add_plugin_page' ) );
        add_action( 'admin_init', array( $this, 'page_init' ) );
    }


    /**
     * Add options page
     */
    public function add_plugin_page()
    {
        add_options_page(
            'Settings Admin', 'My Settings', 'manage_options', 'my-setting-admin', array(
            $this, 'create_admin_page' )
        );
    }


    /**
     * Options page callback
     */
    public function create_admin_page()
    {
        $this->options = get_option( $this->prefix . 'option_name' );
?>
        <div class="wrap">
            <?php screen_icon(); ?>
            <h2>My Settings</h2>           
            <form method="post" action="options.php">
                <?php
                settings_fields( 'my_option_group' );
                do_settings_sections( 'my-setting-admin' );
                submit_button();
                ?>
            </form>
        </div>
        <?php
    }


    /**
     * Register and add settings
     */
    public function page_init()
    {
        $this->prefix = 'uid_' . get_current_user_id() . '_';
        register_setting(
            'my_option_group', // Option group
            $this->prefix . 'option_name', // Option name
            array( $this, 'sanitize' ) // Sanitize
        );
        add_settings_section(
            'setting_section_id', // ID
            'My Custom Settings', // Title
            array( $this, 'print_section_info' ), // Callback
            'my-setting-admin' // Page
        );
        add_settings_field(
            'id_number', // ID
            'ID Number', // Title 
            array( $this, 'id_number_callback' ), // Callback
            'my-setting-admin', // Page
            'setting_section_id' // Section           
        );
        add_settings_field(
            'id_check', 'Title', array( $this, 'id_check_callback' ), 'my-setting-admin', 'setting_section_id'
        );
    }


    /**
     * Sanitize each setting field as needed
     *
     * @param array $input Contains all settings fields as array keys
     */
    public function sanitize( $input )
    {
        if( !is_numeric( $input['id_number'] ) )
            $new_input['id_number'] = '';
        else
            $new_input['id_number'] = esc_sql( $input['id_number'] );

        if( !empty( $input['id_check'] ) )
            $new_input['id_check'] = esc_sql( $input['id_check'] );

        return $new_input;
    }


    /**
     * Print the Section text
     */
    public function print_section_info()
    {
        print 'Enter your settings below:';
    }


    /**
     * Get the settings option array and print one of its values
     */
    public function id_number_callback()
    {
        printf(
            '<input type="text" id="id_number" name="%s" value="%s" />', 
            $this->prefix . 'option_name[id_number]', 
            $this->options['id_number']
        );
    }


    /**
     * Get the settings option array and print one of its values
     */
    public function id_check_callback()
    {
        printf(
            '<input id="%1$s" name="%2$s[%1$s]" type="checkbox" %3$s />', 
            'id_check', 
            $this->prefix . 'option_name', 
            checked( isset( $this->options['id_check'] ), true, false )
        );
    }


}

if( is_admin() )
    $my_settings_page2 = new MySettingsPage2();