Neither. register_activation_hook( __FILE__, ‘trigger_me’ ); function trigger_me() { if ( !wp_next_scheduled( ‘my_plugin_cron’ ) ) { wp_schedule_event(time(), ‘hourly’, ‘my_plugin_cron’); } } Why parse code on every request when you don’t need to?
One problem with the way WordPress handles hooks is that to remove a specific hook with an OOP callback, you must have access to the exact same instance of the class as when the callback was added. This is generally easy enough to handle in your own plugins/themes. However, it makes it nearly impossible to … Read more
Your remove_action has to have a priority matching the priority used in add_action. Important: To remove a hook, the $function_to_remove and $priority arguments must match when the hook was added. This goes for both filters and actions. No warning will be given on removal failure. http://codex.wordpress.org/Function_Reference/remove_action In you case, it looks like remove_action(‘wp_head’, ‘theme_metas’); should … Read more
Short answer: no. Long answer: also no. Actions don’t work that way. Edit: To elaborate and make your question totally generic: function foo() { bar(); return 1; } function bar() { // stuff } There is nothing you can put in stuff that will prevent a call to foo() from returning 1, other than halting … Read more
If you add a bulk-action, then you have to react on this action. Simply adding a function doesn’t do anything, you have to call it: class WPSE_List_Table extends WP_List_Table { public function __construct() { parent::__construct( array( ‘singular’ => ‘singular_form’, ‘plural’ => ‘plural_form’, ‘ajax’ => false ) ); } public function prepare_items() { $columns = $this->get_columns(); … Read more
From the Codex: admin_init is triggered before any other hook when a user access the admin area. This hook doesn’t provide any parameters, so it can only be used to callback a specified function. So yes, it’s run on every admin page load.
The save_post action fires When a post is updated and/or published — including when a new post is inserted. <?php add_action( ‘save_post’, ‘wpse41912_save_post’ ); function wpse41912_save_post() { // do stuff } If you want your functions to fire only when a post is being edited, you can hook into edit_post. If you want it to … Read more
Technically, it is possible. But I would use a slightly different approach. If your second plugin is loaded first you get an error. If you want to replace the class in another plugin, it is hard to do this. So hook into plugins_loaded with a specific priority to create the object and use the object … Read more
The correct way is to pass first argument as a unique string which acts as an identifier for the action & any additional arguments after that do_action(‘unique_action_tag’, $parameter1, $parameter2,,,, & so on); To attach functions to this action you’ll do // 10 is the priority, higher means executed first // 2 is number of arguments … Read more
This will handle appending the content to single posts: function yourprefix_add_to_content( $content ) { if( is_single() ) { $content .= ‘Your new content here’; } return $content; } add_filter( ‘the_content’, ‘yourprefix_add_to_content’ );