功能:
add_action函数用来添加一个函数到指定的动作上,当指定的动作被调用的时候,这个函数也就被调用了。
用法:
参数:
$hook
(字符串)(必须)挂载函数的动作名称。
默认值:None
$function_to_add
(回调函数)(必须)挂载的函数,直接填写字符串形式的函数名即可,如果你要挂载类函数可以参考:https://www.endskin.com/hook-object-function/
默认值:None
$priority
(整数)(可选)动作执行的优先级,数值越小越先被执行。
默认值:10
$accepted_args
(整数)(可选)回调函数接收几个参数。
默认值:1
返回值:
(布尔)始终返回 True.
所在位置:
add_action()函数包含在wp-includes/plugin.php中.
源码:
/**
* Hooks a function on to a specific action.
*
* Actions are the hooks that the WordPress core launches at specific points
* during execution, or when specific events occur. Plugins can specify that
* one or more of its PHP functions are executed at these points, using the
* Action API.
*
* @since 1.2.0
*
* @param string $tag The name of the action to which the $function_to_add is hooked.
* @param callback $function_to_add The name of the function you wish to be called.
* @param int $priority Optional. Used to specify the order in which the functions
* associated with a particular action are executed. Default 10.
* Lower numbers correspond with earlier execution,
* and functions with the same priority are executed
* in the order in which they were added to the action.
* @param int $accepted_args Optional. The number of arguments the function accept. Default 1.
* @return bool Will always return true.
*/
function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
return add_filter($tag, $function_to_add, $priority, $accepted_args);
}
示例:
function test_add_action() {
echo '';
}
add_action( 'wp_head', 'test_add_action' );
相关函数:
do_action()
remove_action()
add_filter()
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