我正在开发一个插件，我必须在其中扩展 WP_List_Table 类。我在我的插件文件中扩展了这个类(我不知道这是否是正确的方法？)并像这样包含 WP_List_Table:

if(!class_exists('WP_List_Table')){
   require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}

然后是扩展类的代码，然后我创建了一个表类的实例，如下所示:

<?php

 if ( ! class_exists( 'WP_List_Table' ) ) {
                require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}


 Class Wp_Ban_User extends WP_List_Table
 {

    public function __construct()
    {
             add_action('admin_menu',array($this,'WBU_adminMenu'));
             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
                  ) );      
            $this->prepare_items();
            $this->display();           

    }
     function get_columns() {
        $columns = array(
            'id'    => 'ID',
            'user_login'     => 'User Name',
            'user_email'   => 'User Email'            
        );
        return $columns;
    }


    function column_default( $item, $column_name ) {
        switch( $column_name ) {
            case 'id':
            case 'user_login':
            case 'user_email':

                return $item[ $column_name ];
            default:
                return print_r( $item, true ) ;
        }
    }
    function prepare_items() {

        $example_data = array(
                array(
                        'id'        => 1,
                        'user_login'     => 'vasim',
                        'user_email'    => 'vasim@abc.com'                        
                ),
                array(
                        'id'        => 2,
                        'user_login'     => 'Asma',
                        'user_email'    => 'Asma@abc.com'                        
                ),
                array(
                        'id'        => 3,
                        'user_login'     => 'Nehal',
                        'user_email'    => 'nehal@abc.com'                        
                ),
            );

        $columns = $this->get_columns();
        $hidden = array();
        $sortable = $this->get_sortable_columns();
        $this->_column_headers = array($columns, $hidden, $sortable);
        $this->items = $example_data;
    }

    public function WBU_adminMenu()
    {
            add_menu_page( 'Currently Logged In User', 'Banned User', 'manage_options', 'ban_admin_init', array($this,'ban_admin_init'));
    }
function ban_admin_init(){
        global $wpdb;

        $sql="SELECT * from {$wpdb->prefix}users";
        $sql_result=$wpdb->get_results($sql,'ARRAY_A');
        print_r($sql_result);
        //$this->items=$sql_result;     
    }

}

 global $Obj_Wp_Ban_User;

 $Obj_Wp_Ban_User=new Wp_Ban_User();

但是当我这样做时，我确实得到了这个错误:

Fatal error: Call to undefined function convert_to_screen() in D:\xampp\htdocs\developplugin\wp-admin\includes\class-wp-list-table.php on line 143

我做了一些研究，但不知道如何修复它。

有人知道如何解决这个问题吗？

感谢您的帮助!

最好的问候。

最佳答案

抱歉我的英语不好，我是法语。

我发现了问题。您的类(class)已更正(请参阅代码底部):

<?php
/*
Plugin Name: My List Table Example
*/
 if ( ! class_exists( 'WP_List_Table' ) ) {
    require_once( ABSPATH . 'wp-admin/includes/class-wp-list-table.php' );
}


Class Wp_Ban_User extends WP_List_Table
{

    public 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
                  ) );      
            $this->prepare_items();
            $this->display();           

    }

    function get_columns() {
        $columns = array(
            'id'    => 'ID',
            'user_login'     => 'User Name',
            'user_email'   => 'User Email'            
        );
        return $columns;
    }

    function column_default( $item, $column_name ) {
        switch( $column_name ) {
            case 'id':
            case 'user_login':
            case 'user_email':

                return $item[ $column_name ];
            default:
                return print_r( $item, true ) ;
        }
    }

    function prepare_items() {

        $example_data = array(
                array(
                        'id'        => 1,
                        'user_login'     => 'vasim',
                        'user_email'    => 'vasim@abc.com'                        
                ),
                array(
                        'id'        => 2,
                        'user_login'     => 'Asma',
                        'user_email'    => 'Asma@abc.com'                        
                ),
                array(
                        'id'        => 3,
                        'user_login'     => 'Nehal',
                        'user_email'    => 'nehal@abc.com'                        
                ),
            );

        $columns = $this->get_columns();
        $hidden = array();
        $sortable = $this->get_sortable_columns();
        $this->_column_headers = array($columns, $hidden, $sortable);
        $this->items = $example_data;
    }

}


// Render your admin menu outside the class
function WBU_adminMenu()
{
    add_menu_page( 'Currently Logged In User', 'Banned User', 'manage_options', 'render_admin_page', 'render_admin_page');
}

// Create your menu outside the class
add_action('admin_menu','WBU_adminMenu');

// Render your page outside the class
function render_admin_page(){
    global $wpdb;

    $Obj_Wp_Ban_User=new Wp_Ban_User();
    $Obj_Wp_Ban_User->prepare_items();

    $sql="SELECT * from {$wpdb->prefix}users";
    $sql_result=$wpdb->get_results($sql,'ARRAY_A');
    print_r($sql_result);    
}

这很简单:要解决错误 Call to undefined function convert_to_screen() 你需要:

• 在类外添加菜单
• 在类外添加admin_menu Action
• 在类外呈现您的管理页面

3 天后，它对我有用!

关于php - 调用未定义函数 convert_to_screen()，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40867316/