add_action()给一个动作钩子添加一个回调方法

目录

描述

译文

将函数连接到指定action(动作)。

在Plugin API/Action Reference 上查看动作hook列表。wordpress核心调用do_action() 时触发动作。

原文

Hooks a function on to a specific action.

More specifically, this function will run the function $function_to_add when the event $hook occurs.

This function is an alias to add_filter().

See Plugin API/Action Reference for a list of action hooks. Actions are (usually) triggered when the WordPress core calls do_action().

add_action() 描述

用法

<?php add_action$hook$function_to_add$priority$accepted_args ); ?>

add_action() 用法

参数

$hook

(string) (必填) The name of the action to which $function_to_add is hooked. (See Plugin API/Action Reference for a list of action hooks). Can also be the name of an action inside a theme or plugin file, or the special tag "all", in which case the function will be called for all hooks.

默认值: None

$function_to_add

(callback) (必填) The name of the function you wish to be hooked.

默认值: None

$priority

(int) (可选) Used to specify the order in which the functions associated with a particular action are executed. 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.

默认值: 10

$accepted_args

(int) (可选) The number of arguments the hooked function accepts. In WordPress 1.5.1+, hooked functions can take extra arguments that are set when the matching do_action() or apply_filters() call is run. For example, the action comment_id_not_found will pass any functions that hook onto it the ID of the requested comment.

默认值: 1

add_action() 参数

返回值

(boolean) 

Always True.

add_action() 返回值

示例

Simple Hook

To email some friends whenever an entry is posted on your blog:

Accepted Arguments

A hooked function can optionally accept arguments from the action call, if any are set to be passed. In this simplistic example, the echo_comment_id function takes the $comment_id argument, which is automatically passed to when the do_action() call using the comment_id_not_found filter hook is run.

Using with a Class

To use add_action() when your plugin or theme is built using classes, you need to use the array callable syntax. You would pass the function to add_action() as an array, with your object as the first element, then the name of the class method, like so:

If the class method can be called statically, the approach is much like the way you would a function: you can just pass a string with the full method:

add_action() 示例

注意

To find out the number and name of arguments for an 动作, simply search the code base for the matching do_action() call. For example, if you are hooking into 'save_post', you would find it in post.php:

 <?php do_action'save_post'$post_ID$post$update ); ?> 

Your add_action call would look like:

 <?php add_action'save_post''my_save_post'10); ?> 

And your function would be:

add_action() 注意

历史

添加于 版本 1.2.0

add_action() 历史

源文件

add_action() 函数的代码位于 wp-includes/plugin.php.

add_action() 源文件

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