get_current_screen()-WordPress函数

获取当前屏幕对象
返回＃返回
（WP_Screen | null）当前屏幕对象，或者屏幕未定义时为null。

add_action( 'current_screen', 'wpdocs_this_screen' );
 
/**
 * Run code on the admin widgets page
 */
function wpdocs_this_screen() {
    $currentScreen = get_current_screen();
    if( $currentScreen->id === "widgets" ) {
        // Run some code, only on the admin widgets page
    }
}
//第二个
PAGE               $SCREEN_ID           FILE
-----------------  -------------------  -----------------------
Media Library      upload               upload.php
Comments           edit-comments        edit-comments.php
Tags               edit-post_tag        edit-tags.php
Plugins            plugins              plugins.php
Links              link-manager         link-manager.php
Users              users                users.php
Posts              edit-post            edit.php
Pages              edit-page            edit.php
Edit Site: Themes  site-themes-network  network/site-themes.php
Themes             themes-network       network/themes
Users              users-network        network/users
Edit Site: Users   site-users-network   network/site-users
Sites 
//第三个示例
add_action('trashed_post', 'trash_wpcrm_contact');
function trash_wpcrm_contact($post_id){
    $screen = get_current_screen();
    if('wpcrm-contact' != $screen->post_type){ //this is not our custom post, so let's exit
      return;
    }
    ....
}

//第三个介绍
此函数返回的WP_Screen对象的另一个有用属性$screen->base是'post'为任何自定义后期编辑屏幕设置的属性，并设置'edit'为自定义后期管理表页面，在为其他功能加载自定义CSS /脚本时非常方便在这些页面上。

默认用法
此示例显示如何将上下文帮助添加到使用该add_options_page()函数创建的管理页面。在这里，我们假设你的管理页面有一个slug，my_admin_page并存在于Options选项卡下。
该get_current_screen()示例中使用了该函数。

add_action('admin_menu', 'wpdocs_admin_add_page');
 
/**
 * Add an admin page
 */
function wpdocs_admin_add_page() {
    global $wpdocs_admin_page;
    $wpdocs_admin_page = add_options_page(__('Wpdocs Admin Page', 'wpdocs_textdomain'),
        __('Wpdocs Admin Page', 'wpdocs_textdomain'),
        'manage_options', 'wpdocs_textdomain', 'wpdocs_admin_page');
 
    // Adds my_help_tab when my_admin_page loads
    add_action('load-'.$wpdocs_admin_page, 'wpdocs_admin_add_help_tab');
}
 
/**
 * Add a contextual help tab to the Wpdocs Admin Page
 */
function wpdocs_admin_add_help_tab () {
    global $wpdocs_admin_page;
    $screen = get_current_screen();
 
    /*
     * Check if current screen is Wpdocs Admin Page
     * Don't add help tab if it's not
     */
    if ( $screen->id != $wpdocs_admin_page )
        return;
 
    // Add my_help_tab if current screen is My Admin Page
    $screen->add_help_tab( array(
        'id' => 'wpdocs_help_tab',
        'title' => __('Wpdocs Help Tab'),
        'content' => '<p>'
        . __( 'Descriptive content that will show in Wpdocs Help Tab body goes here.', 'wpdocs_textdomain' )
        . '</p>',
    ) );
}