導航箭頭未顯示幾張圖像

Question

如果您轉到此處 ，然后單擊圖像，則每個圖像都有“下一個”和“上一個”箭頭，但沒有前兩個圖像。 為什么會這樣呢？

<nav class="prev-next">
    <ul>
    <?php
    $next_post = get_next_post();
    $prev_post = get_previous_post();
    $next_post_year = '';
    $previous_post_year = '';
    $previous_post_media = '';
    $next_post_media = '';
    if($next_post) {

    $next_post_id  = ($next_post->ID);
    $years = wp_get_post_terms( $next_post_id, 'years', array( 'fields' => 'ids' ) );
    $medias = wp_get_post_terms( $next_post_id, 'media', array( 'fields' => 'ids' ) );
    $next_post_year = $years[0];
    $next_post_media = $medias[0];

    }
    if($prev_post) {
    $previous_post_id  = ($prev_post->ID);
    $years = wp_get_post_terms( $previous_post_id, 'years', array( 'fields' => 'ids' ) );
    $medias = wp_get_post_terms( $previous_post_id, 'media', array( 'fields' => 'ids' ) );
    $previous_post_year = $years[0];
    $previous_post_media = $medias[0];

    }
    $show_next = false;
    if($next_post_year == $current_post_year && $next_post_media == $current_post_media) {
        $show_next = true;
    }
    $show_prev = false;
    if($previous_post_year == $current_post_year && $previous_post_media == $current_post_media) {
        $show_prev = true;

    }
    ?>
        <?php /*<li class="prev"><?php previous_post('%', '&lsaquo; Previous', 'no'); ?></li>
        <li class="next"><?php next_post('%' , 'Next &rsaquo;', 'no'); ?></li>*/ ?>
        <?php if($show_next) { ?>
        <li class="prev"><?php next_post('%' , '&lsaquo; Previous', 'no'); ?></li>
        <?php } ?>
        <?php if($show_prev) { ?>
        <li class="next"><?php previous_post('%', 'Next &rsaquo;', 'no'); ?></li>
        <?php } ?>      
    </ul>
</nav>

如果查看未顯示箭頭的圖像的單個圖像頁面的代碼，則會看到在這些頁面上甚至沒有創建下一個和上一個<li> 。

Answer 1

<li>未創建，因為不滿足以下條件： <?php if($show_next) { ?> 。 這個條件是關於檢查年份是否匹配： if($next_post_year == $current_post_year 。檢查，是否真的需要這個條件。