do_action( string $hook_name, mixed $arg )

使用示例

• 示例1

  实例

  # ======= Somewhere in a (mu-)plugin, theme or the core ======= #
  
  /**
   * You can have as many arguments as you want,
   * but your callback function and the add_action call need to agree in number of arguments.
   * Note: `add_action` above has 2 and 'i_am_hook' accepts 2. 
   * You will find action hooks like these in a lot of themes & plugins and in many place @core
   * @see: https://codex.wordpress.org/Plugin_API/Action_Reference
   */
  
  # ======= e.g., inside your functions.php file ======= #
  
  /**
   * Define callback function
   * Inside this function you can do whatever you can imagine
   * with the variables that are loaded in the do_action() call above.
   */
  function wpdocs_who_is_hook( $a, $b ) {
  	echo '<code>';
  		print_r( $a ); // `print_r` the array data inside the 1st argument
  	echo '</code>';
  
  	echo '<br />'.$b; // echo linebreak and value of 2nd argument
  }
  
  // then add it to the action hook, matching the defined number (2) of arguments in do_action
  // see [https://codex.wordpress.org/Function_Reference/add_action] in the Codex 
  
  // add_action( $tag, $function_to_add, $priority, $accepted_args );
  add_action( 'wpdocs_i_am_hook', 'wpdocs_who_is_hook', 10, 2 );
  
  // Define the arguments for the action hook
  $a = array(
  	'eye patch'  => 'yes',
  	'parrot'     => true,
  	'wooden leg' => 1
  );
  $b = __( 'And Hook said: "I ate ice cream with Peter Pan."', 'textdomain' ); 
  
  // Executes the action hook named 'i_am_hook'
  do_action( 'wpdocs_i_am_hook', $a, $b );
  

  结果：

  Array ( 
  	['eye patch'] => 'yes'
  	['parrot'] => true
  	['wooden leg'] => 1
  )
  And hook said: "I ate ice cream with Peter Pan."
  

• 示例2

  BIG GOTCHA:

  调用do_action时，如果传入的$arg是一个具有单个对象的数组，则它将传入该obejct，而不是数组。但是，如果数组的单个项不是数组，则它不会执行相同的switcheroo

  例如，

  function my_callback( $should_be_an_array ){
     var_dump($should_be_an_array);
  }
  add_action( 'my_action', 'my_callback' );
  do_action( 'my_action', array(new stdclass()) );
  do_action( 'my_action', array( 'array_item_thats_not_an_object') );
  

  回显

  object(stdClass)[420]
  array (size=1)
    0 => string 'array_item_thats_not_an_object' (length=30)
  

  请注意，我们第一次传入一个包含stdclass的数组时，回调函数只接收stdclass，而不是数组

• 示例3

  相关：

  add_action()
  remove_action()