chooseDisplay example

// This will set the default display and instantiate the default display       // plugin.       $this->initDisplay();
    }

    // If no display ID is passed, we either have initialized the default or     // already have a display set.     if (!isset($display_id)) {
      return TRUE;
    }

    $display_id = $this->chooseDisplay($display_id);

    // Ensure the requested display exists.     if (!$this->displayHandlers->has($display_id)) {
      trigger_error(new FormattableMarkup('setDisplay() called with invalid display ID "@display".', ['@display' => $display_id]), E_USER_WARNING);
      return FALSE;
    }

    // Reset if the display has changed. It could be called multiple times for     // the same display, especially in the UI.     if ($this->current_display != $display_id) {
      // Set the current display.