Add Default Callback Functions for add_settings_field()

[mordauk]

By default, when creating options in plugins and themes, every developer is required to create custom callback functions for rendering their option's HTML. The HTML for most options is nothing more than a standard INPUT field, a SELECT field, TEXTAREA field, etc, so there's really no reason there shouldn't be default callback options in place.

For example, if I have a plugin that registers one text field option in the General settings page, it really doesn't make sense that I should be forced to create a callback function, especially not when probably 99% of all text fields are outputted in exactly the same way:

<input name="FIELD NAME" id="FIELD ID" value="FIELD VALUE" class="regular-text"/>
<div class="description">The description of the field (if present)</div>

With default field callbacks available, developers can do this:

function pw_register_settings() {
	register_setting( 'general', 'pw_sample_option', 'esc_attr' );
	add_settings_section( 'pw_sample_section', 'This is a Sample Section', 'pw_sample_section_cb', 'general');
	add_settings_field( 'pw_sample_option', 'A Sample Setting', 'text', 'general', 'pw_sample_section', array( 'description' => 'The field description' ) );
}
add_action('admin_init', 'pw_test_settings');

function pw_sample_section_cb() {
	// this is the section HTML (if you want it)
}

This is much simpler than also having to write the callback function to render the HTML for the option.

The patch attached adds the following default callbacks:

• text
• textarea
• select
• radio
• checkbox
• checkbox_group

For select, radio, and checkbox groups, the options are passed as an array of "choices" in the last, optional $args parameter for add_settings_field():

$options = array( 
	'one' => 'The Choice Name',
	'two' => 'The Second name', 
	'three' => 'The Third option'
);
add_settings_field( 'pw_sample_option', 'A Sample Setting', 'select', 'general', 'pw_sample_section', array( 'choices' => $options, 'description' => 'This is a select' ) );

When a user wants to create a custom callback function, this is still allowed as call_user_func() is the default in the $field['callback'] switch statement for the do_settings_fields() function.

Adds default callbacks for add_settings_field()

Overloading the $callback parameter seems like a slick solution. +1