请注意$file 在里面register_activation_hook( $file, $callback ), 应该等于主插件文件的路径，但当您将其作为__FILE__ 那就不一样了！这意味着永远不会调用您的回调。

我还建议在函数名称前加前缀，以避免可能的名称冲突或使用名称空间。

法典中的更多内容here.

Update

深入了解函数的定义有助于提供信息：

/**
 * Set the activation hook for a plugin.
 *
 * When a plugin is activated, the action \'activate_PLUGINNAME\' hook is
 * called. In the name of this hook, PLUGINNAME is replaced with the name
 * of the plugin, including the optional subdirectory. For example, when the
 * plugin is located in wp-content/plugins/sampleplugin/sample.php, then
 * the name of this hook will become \'activate_sampleplugin/sample.php\'.
 *
 * When the plugin consists of only one file and is (as by default) located at
 * wp-content/plugins/sample.php the name of this hook will be
 * \'activate_sample.php\'.
 *
 * @since 2.0.0
 *
 * @param string   $file     The filename of the plugin including the path.
 * @param callable $function The function hooked to the \'activate_PLUGIN\' action.
 */
function register_activation_hook($file, $function) {
    $file = plugin_basename($file);
    add_action(\'activate_\' . $file, $function);
}

这是对应的do_action 在中调用插件acitvationactivate_plugin() 功能：

/**
 * Fires as a specific plugin is being activated.
 *
 * This hook is the "activation" hook used internally by register_activation_hook().
 * The dynamic portion of the hook name, `$plugin`, refers to the plugin basename.
 *
 * If a plugin is silently activated (such as during an update), this hook does not fire.
 *
 * @since 2.0.0
 *
 * @param bool $network_wide Whether to enable the plugin for all sites in the network
 *                           or just the current site. Multisite only. Default is false.
 */
  do_action( "activate_{$plugin}", $network_wide );

Example

让我们通过一个真正的插件来了解这一点。

因此，以WooCommerce插件为例，该插件具有主插件文件：

/full/path/to/wp-content/woocommerce/woocommerce.php 

它在哪里defines:

register_activation_hook( __FILE__, array( \'WC_Install\', \'install\' ) );

在哪里$file 是__FILE__ 或

/full/path/to/wp-content/woocommerce/woocommerce.php 

然后线路：

$file = plugin_basename( $file );

成为：

$file = plugin_basename( \'/full/path/to/wp-content/woocommerce/woocommerce.php\' );

这就产生了：

$file = \'woocommerce/woocommerce.php\';

然后动态挂钩：

add_action(\'activate_\' . $file, $function);

生成：

add_action(\'activate_woocommerce/woocommerce.php\', $function);

因此，如果WooCommerce将注册激活挂钩放在一个特殊文件中，例如。

/full/path/to/wp-content/woocommerce/include/activation.php

那么这就是__FILE__ 我们将注册以下操作：

add_action(\'activate_woocommerce/include/activation.php\', $function);

但是没有do_action() 打电话叫那个。

相反，他们可能存储主插件文件路径，以便在其他地方使用，就像他们在主插件文件中所做的那样here:

$this->define( \'WC_PLUGIN_FILE\', __FILE__ );

希望有帮助！