plugin-development - Read For Learn

Is there a hook for when you switch themes?

There is a ‘switch_theme’ action that runs right after the theme is switched. function my_on_switch_theme($new_theme) { $current_themes = wp_get_themes(); /* Fixed deprecated function */ $new_theme_info = $current_themes[$new_theme]; /* $new_theme_info should now be an associative array with the following: $new_theme_info[‘Title’]; $new_theme_info[‘Version’]; $new_theme_info[‘Parent Theme’]; $new_theme_info[‘Template Dir’]; $new_theme_info[‘Stylesheet Dir’]; $new_theme_info[‘Template’]; $new_theme_info[‘Stylesheet’]; $new_theme_info[‘Screenshot’]; $new_theme_info[‘Description’]; $new_theme_info[‘Author’]; $new_theme_info[‘Tags’]; $new_theme_info[‘Theme Root’]; $new_theme_info[‘Theme … Read more

How to implement bulk actions in my plugin?

Unfortunately there isn’t a way of doing this yet, see this trac report. While it would have been possible to add actions to the bulk-actions drop-down menu, there doesn’t exist (yet) a way of handling custom actions. It seems that WordPress deliberately prevents you from adding custom actions (presumably until it’s decided how bulk actions … Read more

How to delete custom taxonomy terms in plugin’s uninstall.php?

Using the uninstall hook would be legitimate if it worked, but it dumps the same error as the uninstall file. It would have more chances of working as it loads the main plugin file to perform the uninstall function, but if the taxonomy is not registered anymore (and it is not, as we need to … Read more

Uninstalling a plugin: delete all options with specific prefix

Replace “myplugin_” with your prefix: global $wpdb; $plugin_options = $wpdb->get_results( “SELECT option_name FROM $wpdb->options WHERE option_name LIKE ‘myplugin_%'” ); foreach( $plugin_options as $option ) { delete_option( $option->option_name ); }

Is There A Hook To Process The Content Of The Text Widget?

Filter widget_text (for the text) widget_title (for the title) Example function add_smiley($content) { $new_content=””; $new_content.= $content . ‘:)’; return $new_content; } add_filter(‘widget_text’, ‘add_smiley’); Note that this works only for the content so not if you have a widget with only a title. Reference http://codex.wordpress.org/WordPress_Widgets https://stackoverflow.com/questions/1385954/do-wordpress-widget-or-sidebar-hooks-exist https://stackoverflow.com/search?q=wordpress+widget

Check for success of $wpdb->update() correctly

The correct way is with === FALSE which differentiates from equalling zero, which is what a succesful query with no results returns. if( $wpdb->update($tableName,array(‘opt_value’=>$cInfo),array(‘opt_name’=>’showWeatherWidget’)) === FALSE) //show failure message else // show success message

Creating a WordPress admin page without a menu for a plugin

I am less convinced that I know what you are doing than I once was. // Add menu and pages to WordPress admin area add_action(‘admin_menu’, ‘myplugin_create_top_level_menu’); function myplugin_create_top_level_menu() { // This is the menu on the side add_menu_page( ‘MyPlugin’, ‘MyPlugin’, ‘manage_options’, ‘myplugin-top-level-page’ ); // This is the first page that is displayed when the menu … Read more

Using filters and actions for plugin API?

Surely this approach has some benefits, but has also some issues. It’s not really easy to use If the target of your plugin are WordPress developers, they will be very familiar with plugin API, but end users are not. For a non-developer, something like: $data = give_me_the_data(); It’s easier to understand, remember and type than: … Read more

Where can I find a schema of wordpress plugin core architecture?

There is not much to it, really. During the loading of WordPress engine wp-settings.php file is processed. Among other things this files calls wp_get_active_and_valid_plugins() function, that gets list of activated (through admin interface) plugins from active_plugins option (stored in database). For each active plugin its main file (the one holding plugin header) is included and … Read more

Email verification for new users

I had a very similar problem which I solved the other day. In my case I wanted to allow users to choose their own password, and then activate their account via email. There’s alot to this, so I’ll just outline how to I achieved the e-mail verification. First, I used user_register (runs when a user … Read more

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