我是updating the codex page example for action hooks, 在游戏中完成一些可重用的功能（最初是针对这里的一些Q@WA）。但后来我遇到了一个以前没有意识到的问题：在挂接到一个函数以修改变量的输出后，我再也无法决定是要回显输出还是只返回它。
The Problem: 我可以修改传递给do_action 用回调函数钩住。使用变量修改/添加的所有内容仅在回调函数中可用，但在do_action 在原始函数内部调用。
很高兴：我将其修改为一个工作示例，因此您可以将其复制/粘贴到functions.php 无需任何努力即可归档并查看/测试问题。
示例：
句柄数据函数
这是Handle\\u data\\u fn。文档记录有点过多，因为它应该作为如何解析默认值并将其与其他参数合并的指南
在do\\u action（）调用之后，您可以在函数末尾看到问题。
/**
* The "global" data handle function
*
* This function can serve a lot of different purposes.
* Incl. merging db values from an options entry with input arguments.
*
* Throws a fully translateable Error if no database option name was specified.
* Tells you from which file the Error was triggered and in which line you should search it.
* Also tells you the "hook_data_handle_$args[\'UID\']" name of the action hook where the Error occured.
*
* Uses of external function calls in order of their appearance inside the function:
* @uses: isset() - @link: http://php.net/manual/en/function.isset.php
* @uses: wp_die() - @link: http://codex.wordpress.org/Function_Reference/wp_die
* @uses: printf() - @link: http://php.net/manual/en/function.printf.php
* @uses: _e() - @link: http://codex.wordpress.org/Function_Reference/_e (i18n function)
* @uses: apply_filters() - @link: http://codex.wordpress.org/Function_Reference/apply_filters
* @uses: wp_parse_args() - @link: http://codex.wordpress.org/Function_Reference/wp_parse_args
* @uses: extract() - @link: http://php.net/manual/en/function.extract.php
* @uses: get_option() - @link: http://codex.wordpress.org/Function_Reference/get_option
* @uses: do_action() - @link: http://codex.wordpress.org/Function_Reference/do_action
* @uses: return - @link: http://php.net/manual/en/function.return.php
*
* @param: (array) mixed $args | array of arguments - `$args[\'UID\']` is always a must have
* @param: $database | true if you want to get and modify some db-option - `$args[\'name\']` then is a must have
* @param: $output | result from the function - @internal: should not get set
*/
function handle_data_fn( $args = array() )
{
// abort if we ain\'t got some unique identifier as argument
if ( !isset( $args[\'UID\']) )
return;
// Trigger Error if an option should get retrieved from the database,
// but no option name was specified
if ( !isset( $args[\'name\'] ) )
wp_die(
printf(
_e(
\'You have to specify the "name" of a db-entry as argument inside a handle_data_fn at for the action hook: %1$s.\'."\\n".
\'Error triggered inside: file name %2$s (line number %3$s)\'
)
,\'some_textdomain\'
)
,\'hook_data_handle_\'.$args[\'UID\'].\'`\'
,__FILE__
,__LINE__
);
// setup default arguments
$defaults = (
array(
\'UID\' => null // DB/css: #id | used to identify the data inside your database - $name[$ID] - can be used as css #id too
,\'name\' => null // name of DB field, should be a constant when fn get\'s triggered - just here for completeness, not needed
,\'args\' => array( // $arguments the function can handle - put default arguments in here as array data
// \'classes\' => null // css: .class - example
)
,\'output\' => \'\'
,\'echo\' => false // if you want to echo the output or just save it in a var for later modifying
)
);
// filter defaults
$defaults = apply_filters( \'filter_defaults_\'.$args[\'UID\'], $defaults );
// merge defaults with input arguments
$args = wp_parse_args( $args, $defaults );
extract( $args, EXTR_SKIP );
// in case you want to call the global function again,
// but for some reason need to modify the merged result of defaults & arguments
$args = apply_filters( \'filter_args_\'.$args[\'UID\'], $args );
// retrieve the database option
if ( isset( $args[\'name\'] ) )
$options = get_option( $args[\'name\'] );
# >>> start building $output
// if true, echo the $output
if ( isset( $args[\'echo\'] ) )
{
if ( $args[\'echo\'] === true )
{
// do stuff here - your argument is the initial array
do_action( \'hook_data_handle_\'.$args[\'UID\'], $args, $options );
// Test output inside handle_fn:
echo \'<pre>From inside handle_fn: \';
print_r($args);
echo \'</pre>\';
return;
}
}
// else just return the $output
// HOW CAN I NOT ECHO THE DATA HERE.
// STORING THE do_action return VALUE DOESN\'T WORK.
// NEITHER DOES JUST returnING IT INSIDE THE CALLBACK FN \'modify_args_fn\' BELOW
do_action( \'hook_data_handle_\'.$args[\'UID\'], $args, $options );
return;
# <<< end building $output
}
回调函数用于a）构建初始数组和b）修改输出。
/**
* EXAMPLE for how to add initial data to the handle_data_fn function.
*
* @param (array) mixed $args
*/
function build_args_fn ( $args ) {
// build initial array
$args = array(
\'UID\' => \'whatever_UID\'
,\'name\' => \'some_options_name\'
,\'args\' => array(
\'class\' => \'example-wrap\'
)
,\'echo\' => true
);
handle_data_fn( $args );
}
// \'some_hook\' is some hook in a template file where the output should get echoed.
add_action( \'some_hook\', \'build_args_fn\', 0, 1 );
/**
* EXAMPLE for how to add content and modify the options from the DB inside a handle_data_fn function.
*
* @param (array) mixed $args
* @param (array) mixed $options | db-options retrieved inside the oxo_parse function
*/
function modify_args_fn ( $args, $options )
{
$args[\'output\'] .= \'<div class="container">\';
$args[\'output\'] .= \'<div class="\'.$args[\'args\'][\'class\'].\'">\';
$args[\'output\'] .= $options;
$args[\'output\'] .= \'</div>\';
$args[\'output\'] .= \'</div>\';
// Test output inside callback fn
echo \'<pre>From inside callback: \';
print_r($args);
echo \'</pre>\';
// HERE\'S THE PROBLEM. I CAN\'T SIMPLE return IT, BECAUSE IT WOULDN\'T BE AVAILABLE INSIDE MY \'data_handle_fn\'.
# return $args[\'output\'];
// I HAVE TO PRINT IT TO GET SOME OUTPUT. THE $args[\'output\'] IS NOT AVAILABLE INSIDE THE \'handle_data_fn\' AFTER THE do_action CALL.
return print $args[\'output\'];
}
// Name of the hook comes from \'UID\' argument in \'build_args_fn\' combined with \'hook_data_handle_\'
add_action ( \'hook_data_handle_whatever_UID\', \'modify_args_fn\', 10, 2 );
感谢提供任何信息（&A）；有关此问题的帮助。
