wordpress中是否是手机端的判断

关于WordPress中的是否是手机端的判断WordPress中是有其代码的，其函数为：

function wp_is_mobile() {
	if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
		$is_mobile = false;
	} elseif ( strpos( $_SERVER['HTTP_USER_AGENT'], 'Mobile' ) !== false // Many mobile devices (all iPhone, iPad, etc.)
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Android' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Silk/' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Kindle' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'BlackBerry' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mini' ) !== false
		|| strpos( $_SERVER['HTTP_USER_AGENT'], 'Opera Mobi' ) !== false ) {
			$is_mobile = true;
	} else {
		$is_mobile = false;
	}

	/**
	 * Filters whether the request should be treated as coming from a mobile device or not.
	 *
	 * @since 4.9.0
	 *
	 * @param bool $is_mobile Whether the request is from a mobile device or not.
	 */
	return apply_filters( 'wp_is_mobile', $is_mobile );
}

最后呢返回一个钩子，我们也可以用这个钩子添加一些判断，不过一般情况的话就用它就行了，至于怎么使用这个过滤钩子，我们需要看一下这个过滤钩子是怎么写的：

// The filter callback function.
function example_callback( $string, $arg1, $arg2 ) {
    // (maybe) modify $string.
    return $string;
}
add_filter( 'example_filter', 'example_callback', 10, 3 );

/*
 * Apply the filters by calling the 'example_callback()' function
 * that's hooked onto `example_filter` above.
 *
 * - 'example_filter' is the filter hook.
 * - 'filter me' is the value being filtered.
 * - $arg1 and $arg2 are the additional arguments passed to the callback.
$value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );

可以看到其判断是由http请求的UA中获得的，在WordPress这个文件下，其实还有一些UA的判断，比如$is_edge；还有一些服务器环境的判断，比如$is_nginx。大家可以在这个文件下查看：/wp-includes/vars.php