Php 更新到4.7后不显示页面模板选项

我使用这个插件为页面添加了特定的模板

class PageTemplater {
  protected $plugin_slug;
  private static $instance;
  protected $templates;

  public static function get_instance() {
    if( null == self::$instance ) {
      self::$instance = new PageTemplater();
    }
    return self::$instance;
  }

  private function __construct() {
    $this->templates = array();

    add_filter('page_attributes_dropdown_pages_args', array($this, 'register_project_templates'));
//    add_filter('wp_insert_post_data', array($this, 'register_project_templates'));
    add_filter('template_include', array($this, 'view_project_template'));

    $this->templates = array(
      'page-json.php'     => 'JSON list',
    );
  }

  public function register_project_templates( $atts ) {

    // Create the key used for the themes cache
    $cache_key = 'page_templates-' . md5( get_theme_root_uri() . '/' . get_stylesheet() );

    // Retrieve the cache list.
    // If it doesn't exist, or it's empty prepare an array
    $templates = wp_get_theme()->get_page_templates();
    if ( empty( $templates ) ) {
      $templates = array();
    }

    // New cache, therefore remove the old one
    wp_cache_delete( $cache_key , 'themes');

    // Now add our template to the list of templates by merging our templates
    // with the existing templates array from the cache.
    $templates = array_merge( $templates, $this->templates );

    // Add the modified cache to allow WordPress to pick it up for listing
    // available templates
    wp_cache_add( $cache_key, $templates, 'themes', 1800 );

    return $atts;
  }

  /**
    * Checks if the template is assigned to the page
    */
  public function view_project_template( $template ) {
    global $post;

    if (!isset($this->templates[get_post_meta( $post->ID, '_wp_page_template', true)])) {

    }

    $file = plugin_dir_path(__FILE__) . get_post_meta($post->ID, '_wp_page_template', true);

    // Just to be safe, we check if the file exists first
    if (file_exists($file)) {
      return $file;
    } else {
      echo $file;
    }

    return $template;
  }
}
add_action( 'plugins_loaded', array( 'PageTemplater', 'get_instance' ) );

但当我将WordPress更新为4.7页面模板时，选项停止显示。也许我使用了一些不推荐使用的函数

请提供帮助。

固定代码：

// Add a filter to the attributes metabox to inject template into the cache.
    if ( version_compare( floatval( get_bloginfo( 'version' ) ), '4.7', '<' ) ) {

        // 4.6 and older
        add_filter(
            'page_attributes_dropdown_pages_args',
            array( $this, 'register_project_templates' )
        );

    } else {

        // Add a filter to the wp 4.7 version attributes metabox
        add_filter(
            'theme_page_templates', array( $this, 'add_new_template' )
        );

    }
/**
 * Adds our template to the page dropdown for v4.7+
 *
 */
public function add_new_template( $posts_templates ) {
    $posts_templates = array_merge( $posts_templates, $this->templates );
    return $posts_templates;
}

//将筛选器添加到属性元框中，以将模板注入缓存。
if（version_compare（floatval（get_bloginfo（'version'）），'4.7'，'p>固定代码：

// Add a filter to the attributes metabox to inject template into the cache.
    if ( version_compare( floatval( get_bloginfo( 'version' ) ), '4.7', '<' ) ) {

        // 4.6 and older
        add_filter(
            'page_attributes_dropdown_pages_args',
            array( $this, 'register_project_templates' )
        );

    } else {

        // Add a filter to the wp 4.7 version attributes metabox
        add_filter(
            'theme_page_templates', array( $this, 'add_new_template' )
        );

    }
/**
 * Adds our template to the page dropdown for v4.7+
 *
 */
public function add_new_template( $posts_templates ) {
    $posts_templates = array_merge( $posts_templates, $this->templates );
    return $posts_templates;
}

//将筛选器添加到属性元框中，以将模板注入缓存。
if（version_compare（floatval（get_bloginfo（'version'）），'4.7'，'