在WordPress文章段落后添加自定义内容

如果想在WordPress文章段落后添加自定义内容，比如在文章第二段后添加广告，可以尝试用下面的代码：

// 在文章第二段之后插入内容
add_filter( 'the_content', 'prefix_insert_post_ads' );
function prefix_insert_post_ads( $content ) {
	$ad_code = '<div>添加的文字</div>';
	if ( is_single() && ! is_admin() ) {
		return prefix_insert_after_paragraph( $ad_code, 2, $content );
	}
return $content;
}

// 主要函数
function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
	$closing_p = '</p>';
	$paragraphs = explode( $closing_p, $content );
	foreach ($paragraphs as $index => $paragraph) {
		if ( trim( $paragraph ) ) {
			$paragraphs[$index] .= $closing_p;
		}
		if ( $paragraph_id == $index + 1 ) {
			$paragraphs[$index] .= $insertion;
		}
	}
	return implode( '', $paragraphs );
}

分别在段落2、4、6后面添加不同的内容:

add_filter( 'the_content', 'add_ads_to_content' );
function add_ads_to_content( $content ) {
	$ads = array(
		2 =>  'ad code 1', // paragraph_id => ad_code
		4 => 'ad code 2', // paragraph_id => ad_code
		6 => 'ad code 3' // paragraph_id => ad_code
	);

	if ( is_single() && ! is_admin() ) {
		foreach ($ads as $paragraph_id => $ad_code) {
			$content = prefix_insert_after_paragraph( $ad_code, $paragraph_id, $content );
		}
	}
	return $content;
}

function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
	$closing_p = '</p>';
	$paragraphs = explode( $closing_p, $content );
	foreach ($paragraphs as $index => $paragraph) {
		if ( trim( $paragraph ) ) {
			$paragraphs[$index] .= $closing_p;
		}
		if ( $paragraph_id == $index + 1 ) {
			$paragraphs[$index] .= $insertion;
		}
	}
	return implode( '', $paragraphs );
}

如果只显示在某个分类文章中添加，也可以这么写

add_filter( 'the_content', 'prefix_insert_post_ads' );
function prefix_insert_post_ads( $content ) {
	$ad_code = '<div>自定义文字</div>';
		if ( is_single() && ! is_admin() && in_category('29') ) {
		return prefix_insert_after_paragraph( $ad_code, $content );
	}
	return $content;
}

function prefix_insert_after_paragraph( $insertion, $content ) {
	$closing_p = '</p>';
	$paragraphs = explode( $closing_p, $content );
	$paragraph_id = round(count($paragraphs) / 2);
	foreach ($paragraphs as $index => $paragraph) {
		if ( trim( $paragraph ) ) {
			$paragraphs[$index] .= $closing_p;
		}
		if ( $paragraph_id == $index + 1 ) {
		$paragraphs[$index] .= $insertion;
		}
	}
	return implode( '', $paragraphs );
}