WordPress开发函数adjacent_image_link()，显示下一个或上一个图像链接，该链接具有相同的文章父。

用法：

adjacent_image_link( bool $prev = true, string|int[] $size = ‘thumbnail’, bool $text = false )

描述：

从$post全局变量中检索当前附件对象。

参数：

$prev

(bool) (可选) 是否显示下一个(false)或上一个(true)链接。

默认值: true

$size

(string|int[]) (可选) 图像的大小。接受任何注册的图像大小名称，或以像素为单位的宽度和高度值数组(按此顺序)。

默认值: ‘thumbnail’

$text

(bool) (可选) 链接文本。

默认值: false

来源：

文件: wp-includes/media.php

function adjacent_image_link( $prev = true, $size = ‘thumbnail’, $text = false ) {

$post = get_post();

$attachments = array_values(

get_children(

array(

‘post_parent’ => $post->post_parent,

‘post_status’ => ‘inherit’,

‘post_type’ => ‘attachment’,

‘post_mime_type’ => ‘image’,

‘order’ => ‘ASC’,

‘orderby’ => ‘menu_order ID’,

)

)

);

foreach ( $attachments as $k => $attachment ) {

if ( (int) $attachment->ID === (int) $post->ID ) {

break;

}

}

$output = ”;

$attachment_id = 0;

if ( $attachments ) {

$k = $prev ? $k – 1 : $k + 1;

if ( isset( $attachments[ $k ] ) ) {

$attachment_id = $attachments[ $k ]->ID;

$attr = array( ‘alt’ => get_the_title( $attachment_id ) );

$output = wp_get_attachment_link( $attachment_id, $size, true, false, $text, $attr );

}

}

$adjacent = $prev ? ‘previous’ : ‘next’;

/**

* Filters the adjacent image link.

*

* The dynamic portion of the hook name, `$adjacent`, refers to the type of adjacency,

* either ‘next’, or ‘previous’.

*

* @since 3.5.0

*

* @param string $output Adjacent image HTML markup.

* @param int $attachment_id Attachment ID

* @param string|int[] $size Requested image size. Can be any registered image size name, or

* an array of width and height values in pixels (in that order).

* @param string $text Link text.

*/

echo apply_filters( “{$adjacent}_image_link”, $output, $attachment_id, $size, $text );

}

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