Simple ways to make admin customizations for WordPress. You know all that brain space you saved for memorizing hooks? Use it for something better. For example, you can...

Add a column to an admin page!

Jigsaw::add_column($post_type, $column_label, $callback_function, $order = 10);

Jigsaw::add_column('slides', 'Preview', function($pid){
  	$data = array();
	$data['post'] = new TimberPost($pid);
	Timber::render('admin/slide-table-preview.twig', $data);
}, 5);

Jigsaw::add_column(array('slides', 'post'), 'Preview', function($pid){
  	$data = array();
	$data['post'] = new TimberPost($pid);
	Timber::render('admin/slide-table-preview.twig', $data);
});

Add a column to the users table!

Jigsaw::add_user_column($column_label, $callback_function, $order = 10);

Jigsaw::add_user_column('Favorite Band', function($uid){
  	echo get_user_meta($uid, 'favorite-band', true);
}, 5);

Remove a column from the admin

Jigsaw::remove_column($post_types, $column_slug);

Jigsaw::remove_column('slides', 'author');

Jigsaw::remove_column(array('slides', 'post'), 'author');

Add something to the admin bar

Jigsaw::add_toolbar_item($label, $url_or_callback_function);

Jigsaw::add_toolbar_item('Clear Cache', function(){
	$total_cache->flush_all();
});

Add a dropdown

Jigsaw::add_toolbar_group($label, $items);

$optionOne = new stdClass();
$optionOne->label = 'All Caches';
$optionOne->action = function(){
	$total_cache->flush_all();
};
$optionTwo = new stdClass();
$optionTwo->label = 'Page Cache';
$optionTwo->action = function(){
	$total_cache->flush_page_cache();
};
$optionThree = array('Home', 'http://localhost');
Jigsaw::add_toolbar_group('Clear Cache', array($optionOne, $optionTwo, $optionThree));

Show an admin notice

Jigsaw::show_notice($message, $level = 'updated');

Jigsaw::show_notice('Cache has been flushed', 'updated');

...or

Jigsaw::show_notice('Error flushing cache, is the plugin activated?', 'error');

Add a CSS file to the admin

Jigsaw::add_css($css_file);

Jigsaw::add_css('css/my-admin-style.css');

Add a JS file to the admin

Jigsaw::add_js($css_file);

Jigsaw::add_js('js/my-admin-script.js');

JigsawPermalinks

Set the base of the author permalink

JigsawPermalinks::set_author_base($base_string);

JigsawPermalinks::set_author_base('writers');

After this you have to reset permalinks to see it working.

Remove a custom post type permalink

JigsawPermalinks::remove_permalink_slug($custom_post_type);

JigsawPermalinks::remove_permalink_slug('event');

or

JigsawPermalinks::remove_permalink_slug(array('event', 'book', 'my_other_cpt'));

Set a custom permalink

JigsawPermalinks::set_permalink($post_type, $structure);

JigsawPermalinks::set_permalink('gallery', '/galleries/%year%/%gallery%');