Create Native Admin Tables In WordPress The Right Way

<?php
//Our class extends the WP_List_Table class, so we need to make sure that it's there
if(!class_exists('WP_List_Table')){
    require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}

class Links_List_Table extends WP_List_Table {

    /**
     * Constructor, we override the parent to pass our own arguments
     * We usually focus on three parameters: singular and plural labels, as well as whether the class supports AJAX.
     */
     function __construct() {
         parent::__construct( array(
        'singular'=> 'wp_list_text_link', //Singular label
        'plural' => 'wp_list_test_links', //plural label, also this well be one of the table css class
        'ajax'  => false //We won't support Ajax for this table
        ) );
     }

    /**
     * Add extra markup in the toolbars before or after the list
     * @param string $which, helps you decide if you add the markup after (bottom) or before (top) the list
     */
    function extra_tablenav( $which ) {
        if ( $which == "top" ){
            //The code that goes before the table is here
            echo"Hello, I'm before the table";
        }
        if ( $which == "bottom" ){
            //The code that goes after the table is there
            echo"Hi, I'm after the table";
        }
    }

    /**
     * Define the columns that are going to be used in the table
     * @return array $columns, the array of columns to use with the table
     */
    function get_columns() {
        return $columns= array(
            'col_link_id'=>__('ID'),
            'col_link_name'=>__('Name'),
            'col_link_url'=>__('Url'),
            'col_link_description'=>__('Description'),
            'col_link_visible'=>__('Visible')
        );
    }

    /**
     * Decide which columns to activate the sorting functionality on
     * @return array $sortable, the array of columns that can be sorted by the user
     */
    public function get_sortable_columns() {
        return $sortable = array(
            'col_link_id'=>array('link_id'),
            'col_link_name'=>array('link_name'),
            'col_link_visible'=>array('link_visible')
        );
    }

    /**
     * Prepare the table with different parameters, pagination, columns and table elements
     */
    function prepare_items() {
        global $wpdb, $_wp_column_headers;
        $screen = get_current_screen();

        /* -- Preparing your query -- */
        $query = "SELECT * FROM $wpdb->links";

        /* -- Ordering parameters -- */
        //Parameters that are going to be used to order the result
        $orderby = !empty($_GET["orderby"]) ? mysql_real_escape_string($_GET["orderby"]) : 'ASC';
        $order = !empty($_GET["order"]) ? mysql_real_escape_string($_GET["order"]) : '';
        if(!empty($orderby) & !empty($order)){ $query.=' ORDER BY '.$orderby.' '.$order; }

        /* -- Pagination parameters -- */
        //Number of elements in your table?
        $totalitems = $wpdb->query($query); //return the total number of affected rows
        //How many to display per page?
        $perpage = 5;
        //Which page is this?
        $paged = !empty($_GET["paged"]) ? mysql_real_escape_string($_GET["paged"]) : '';
        //Page Number
        if(empty($paged) || !is_numeric($paged) || $paged<=0 ){ $paged=1; }
        //How many pages do we have in total?
        $totalpages = ceil($totalitems/$perpage);
        //adjust the query to take pagination into account
        if(!empty($paged) && !empty($perpage)){
            $offset=($paged-1)*$perpage;
            $query.=' LIMIT '.(int)$offset.','.(int)$perpage;
        }

        /* -- Register the pagination -- */
        $this->set_pagination_args( array(
            "total_items" => $totalitems,
            "total_pages" => $totalpages,
            "per_page" => $perpage,
        ) );
        //The pagination links are automatically built according to those parameters

        /* — Register the Columns — */
        $columns = $this->get_columns();
        $hidden = array();
        $sortable = $this->get_sortable_columns();
        $this->_column_headers = array($columns, $hidden, $sortable);

        /* -- Fetch the items -- */
        $this->items = $wpdb->get_results($query);
    }

    /**
     * Display the rows of records in the table
     * @return string, echo the markup of the rows
     */
    function display_rows() {
        //Get the records registered in the prepare_items method
        $records = $this->items;

        //Get the columns registered in the get_columns and get_sortable_columns methods
        list( $columns, $hidden ) = $this->get_column_info();

        //Loop for each record
        if(!empty($records)){foreach($records as $rec){

            //Open the line
            echo '<tr id="record_'.$rec->link_id.'">';
            foreach ( $columns as $column_name => $column_display_name ) {

                //Style attributes for each col
                $class = "class='$column_name column-$column_name'";
                $style = "";
                if ( in_array( $column_name, $hidden ) ) $style = ' style="display:none;"';
                $attributes = $class . $style;

                //edit link
                $editlink  = '/wp-admin/link.php?action=edit&link_id='.(int)$rec->link_id;

                //Display the cell
                switch ( $column_name ) {
                    case "col_link_id": echo '<td '.$attributes.'>'.stripslashes($rec->link_id).'</td>';    break;
                    case "col_link_name": echo '<td '.$attributes.'><strong><a href="'.$editlink.'" title="Edit">'.stripslashes($rec->link_name).'</a></strong></td>'; break;
                    case "col_link_url": echo '<td '.$attributes.'>'.stripslashes($rec->link_url).'</td>'; break;
                    case "col_link_description": echo '<td '.$attributes.'>'.$rec->link_description.'</td>'; break;
                    case "col_link_visible": echo '<td '.$attributes.'>'.$rec->link_visible.'</td>'; break;
                }
            }

            //Close the line
            echo'</tr>';
        }}
    }
}



//Prepare Table of elements
$wp_list_table = new Links_List_Table();
$wp_list_table->prepare_items();

//Table of elements
$wp_list_table->display();


?>