plugin-development - Read For Learn

How to exclude categories from get_categories() select list inside a widget admin panel

Per http://codex.wordpress.org/Class_Reference/WP_Query you would need to prefix the numerical identifier of the array with a minus-sign, such as $query = new WP_Query( ‘cat=-12,-34,-56’ );, which would exclude the categories with the identifier 12, 34 and 56. You could achieve this by changing the get_cats function into the following: function get_cats(){ $exclude_cats = array( get_cat_ID(‘test1’), get_cat_ID(‘test2’), … Read more

dbdelta failing with error: “WordPress database error Table ‘wp_2_myPlugin’ already exists

I’ve never had any luck with dbdelta, it has worked spottily at best, and when I code, that’s just not good enough. My method for handling DB changes is to use database versions. So when I create a plugin, I also set the database version, then if I want to update the database, I do … Read more

Adding tables to dashboard pages programmatically?

Well in that case take a look at this tutorial on how to use the native WP_List_Table

Plugin won’t activate

From stackoverflow: https://stackoverflow.com/questions/2450510/redirect-after-plugin-activation register_activation_hook(__FILE__, ‘my_plugin_activate’); add_action(‘admin_init’, ‘my_plugin_redirect’); function my_plugin_activate() { add_option(‘my_plugin_do_activation_redirect’, true); } function my_plugin_redirect() { if (get_option(‘my_plugin_do_activation_redirect’, false)) { delete_option(‘my_plugin_do_activation_redirect’); wp_redirect(MY_PLUGIN_SETTINGS_URL); } }

Get coordinates of selected area to use in image maps [closed]

I would suggest looking at this StackOverflow post – Image Map Editor – particularly the top answer’s recommendation: imgAreaSelect. imgAreaSelect is a jQuery plugin for selecting a rectangular area of an image. It allows web developers to easily implement image cropping functionality, as well as other user interface features, such as photo notes (like those … Read more

How to call function from another plugin?

The multi-select field you referenced appears to be stored in PHP serialized format, which is used for “storing or passing PHP values around without losing their type and structure”. To unserialize a custom field value you need to use the unserialize() function: $multi_select_field = unserialize( get_post_meta( get_the_ID(), ‘custom_field_key’, true ) );

Adjust query on single

Take a look here: specify meta_key / meta_value condition for prev_post_link and next_post_link Which ultimately leads to this plugin, which accesses the get_adjacent_post function mentioned above: Ambrosite Next/Previous Post Link Plus And looks like it would fit your needs by allowing you to specificy a meta_value for the next/prev post hook.

wp_insert_post generated mixed permalinks

Permalinks in WP do not actually have anything to do with wp_posts.guid any more. I believe that historically they did, and have been left in because of RSS feeds – I.e. changing them would cause peoples feeds to think that the posts had not been read. Your permalink structure is stored within your wp_options table … Read more

insufficient permissions; coding an action for plugin governed by custom capability

You should not use the page parameter in an admin url unless you are going to go to an options page because a check for the ‘manage_options’ capability is the default permissions check. The goal of the ‘Delete Cache’ link is to run an action, then redirect to the current page/post; it is not to … Read more

Many Single Sites, One Plugin directory – adjust plugins_url()

I guess what you are saying is that it then ‘exports’ the wrong system’s xml (I’m not familiar with the plugin) ? Ideally the plugin itself should be including/using the code rather in such a way so that it still knows the context/system in which it is being used irrespective of where the code is … Read more

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