描述:
通过id获取缩略图(特色图像)的图片信息
用法:
<?php wp_get_attachment_image( $attachment_id, $size, $icon, $attr ); ?>
参数:
$attachment_id
(integer) (必填) 附件ID
默认值: None
$size
(string/array) (可选) 图像大小。字符串关键字(缩略图、中、大或全)或以像素表示宽度和高度的两项数组,例如数组(32,32)。从2.5版起,此参数不影响媒体图标的大小,媒体图标始终以其原始大小显示。
默认值: 'thumbnail'
不要使用需要检查所有图像大小的数组,应该考虑使用add_image_size注册大小,以便生成裁剪版本。它比找到最接近的图像更有效.
$icon
(boolean) (可选) 使用媒体图标表示附件。
默认值: 'False'
- 1 (True)
- 0 (False) - 默认
$attr
(string/array) (可选) 查询字符串或属性数组。
默认值: None
示例:
<ul>
<?php if ( have_posts() ) : while ( have_posts() ) : the_post();
$args = array(
'post_type' => 'attachment',
'numberposts' => -1,
'post_status' => null,
'post_parent' => $post->ID
);
$attachments = get_posts( $args );
if ( $attachments ) {
foreach ( $attachments as $attachment ) {
echo '<li>';
echo wp_get_attachment_image( $attachment->ID, 'full' );
echo '<p>';
echo apply_filters( 'the_title', $attachment->post_title );
echo '</p></li>';
}
}
endwhile; endif; ?>
</ul>
源文件:
/**
* Get an HTML img element representing an image attachment
*
* While `$size` will accept an array, it is better to register a size with
* add_image_size() so that a cropped version is generated. It's much more
* efficient than having to find the closest-sized image and then having the
* browser scale down the image.
*
* @since 2.5.0
*
* @param int $attachment_id Image attachment ID.
* @param string|array $size Optional. Registered image size or flat array of height and width
* dimensions. Default 'thumbnail'.
* @param bool $icon Optional. Whether the image should be treated as an icon. Default false.
* @param string|array $attr Optional. Attributes for the image markup. Default empty.
* @return string HTML img element or empty string on failure.
*/
function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false, $attr = '') {
$html = '';
$image = wp_get_attachment_image_src($attachment_id, $size, $icon);
if ( $image ) {
list($src, $width, $height) = $image;
$hwstring = image_hwstring($width, $height);
$size_class = $size;
if ( is_array( $size_class ) ) {
$size_class = join( 'x', $size_class );
}
$attachment = get_post($attachment_id);
$default_attr = array(
'src' => $src,
'class' => "attachment-$size_class",
'alt' => trim(strip_tags( get_post_meta($attachment_id, '_wp_attachment_image_alt', true) )), // Use Alt field first
);
if ( empty($default_attr['alt']) )
$default_attr['alt'] = trim(strip_tags( $attachment->post_excerpt )); // If not, Use the Caption
if ( empty($default_attr['alt']) )
$default_attr['alt'] = trim(strip_tags( $attachment->post_title )); // Finally, use the title
$attr = wp_parse_args($attr, $default_attr);
/**
* Filter the list of attachment image attributes.
*
* @since 2.8.0
*
* @param array $attr Attributes for the image markup.
* @param WP_Post $attachment Image attachment post.
* @param string|array $size Requested size.
*/
$attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size );
$attr = array_map( 'esc_attr', $attr );
$html = rtrim(" $value ) {
$html .= " $name=" . '"' . $value . '"';
}
$html .= ' />';
}
return $html;
}