How to pass arguments from add_settings_field() to the callback function?

Question

I have a function like this:

add_settings_field( 'contact_phone', 'Contact Phone', 'settings_callback', 'general'); 

That works. It calls settings_callback. Cool. The problem I have with this is: I don't want to have to define a callback function for every setting I add, if all I'm doing is echoing out a little bit of stuff.

function settings_callback() { echo '<input id="contact_phone" type="text" class="regular-text" name="contact_phone" />'; } 

Why on earth should I have to do that? The id, class, and name should all be params.

Is there no way to pass params to the settings_callback function? I started looking at the core, got here: http://core.trac.wordpress.org/browser/tags/3.1.3/wp-admin/includes/template.php

..and ran into this $wp_settings_fields global. Where is this defined?

Answer 1

Look at the declaration for the function:

function add_settings_field( $id, $title, $callback, $page, $section = 'default', $args = array() ) { } 

The last parameter takes your arguments and passes them to the callback function.

Example from my plugin Public Contact Data

foreach ($this->fields as $type => $desc) { $handle = $this->option_name . "_$type"; $args = array( 'label_for' => $handle, 'type' => $type ); $callback = array($this, 'print_input_field'); add_settings_field( $handle, $desc, $callback, 'general', 'default', $args ); } 

The function print_input_field() gets these arguments as first parameter:

/** * Input fields in 'wp-admin/options-general.php' * * @see add_contact_fields() * @param array $args Arguments send by add_contact_fields() * @return void */ public function print_input_field( array $args ) { $type = $args['type']; $id = $args['label_for']; $data = get_option( $this->option_name, array() ); $value = $data[ $type ]; 'email' == $type and '' == $value and $value = $this->admin_mail; $value = esc_attr( $value ); $name = $this->option_name . '[' . $type . ']'; $desc = $this->get_shortcode_help( $type ); print "<input type='$type' value='$value' name='$name' id='$id' class='regular-text code' /> <span class='description'>$desc</span>"; } 

No need to touch a global variable.