除了<?php has_sub_field(\'vimeo_id\'); ?> 线我希望这样，如果用户填写了该字段，它就会显示出来。否则，什么也看不出来。但是，当用户没有填写该字段时，它仍会显示。我做错了什么？

<?php if( have_rows(\'project\') ): ?>

    <ul>

        <?php while( have_rows(\'project\') ): the_row(); ?>

            <li><a href="#<?php the_sub_field(\'project_name\'); ?>"><?php the_sub_field(\'project_name\'); ?></a></li>

        <?php endwhile; ?>

    </ul>

    <?php while( have_rows(\'project\') ): the_row(); ?>

        <div id="<?php the_sub_field(\'project_name\'); ?>">

            <?php has_sub_field(\'vimeo_id\'); ?>

                <iframe src="//player.vimeo.com/video/<?php the_sub_field(\'vimeo_id\'); ?>?title=0&amp;byline=0&amp;portrait=0&amp;color=ffffff" width="750" height="300" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>

        </div>

    <?php endwhile; ?>

<?php endif; ?>

除了<?php has_sub_field(\'vimeo_id\'); ?> 线我希望这样，如果用户填写了该字段，它就会显示出来。否则，什么也看不出来。但是，当用户没有填写该字段时，它仍会显示。我做错了什么？

<?php if( have_rows(\'project\') ): ?>

    <ul>

        <?php while( have_rows(\'project\') ): the_row(); ?>

            <li><a href="#<?php the_sub_field(\'project_name\'); ?>"><?php the_sub_field(\'project_name\'); ?></a></li>

        <?php endwhile; ?>

    </ul>

    <?php while( have_rows(\'project\') ): the_row(); ?>

        <div id="<?php the_sub_field(\'project_name\'); ?>">

            <?php has_sub_field(\'vimeo_id\'); ?>

                <iframe src="//player.vimeo.com/video/<?php the_sub_field(\'vimeo_id\'); ?>?title=0&amp;byline=0&amp;portrait=0&amp;color=ffffff" width="750" height="300" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>

        </div>

    <?php endwhile; ?>

<?php endif; ?>