wordpress : Settings API

settings-api

<?php
/*
Plugin Name: Settings API example
Plugin URI: http://example.com/
Description: A complete and practical example of use of the Settings API
Author: WROX
Author URI: http://wrox.com
*/
// Add a menu for our option page
add_action('admin_menu', 'boj_myplugin_add_page');
function boj_myplugin_add_page() {
	add_options_page( 'My Plugin', 'My Plugin', 'manage_options',
	'boj_myplugin', 'boj_myplugin_option_page'
	);
}
// Draw the option page
function boj_myplugin_option_page() {
?>
	<div class="wrap">
		<?php screen_icon(); ?>
		<h2>My plugin</h2>
		<form action="options.php" method="post">
			<?php settings_fields('boj_myplugin_options'); ?>
			<?php do_settings_sections('boj_myplugin'); ?>
			<input name="Submit" type="submit" value="Save Changes"/>
		</form>
	</div>
<?php
}
// Register and define the settings
add_action('admin_init', 'boj_myplugin_admin_init');
function boj_myplugin_admin_init(){
	register_setting( 'boj_myplugin_options', 'boj_myplugin_options',
		'boj_myplugin_validate_options' );
	add_settings_section( 'boj_myplugin_main', 'My Plugin Settings',
		'boj_myplugin_section_text', 'boj_myplugin' );
	add_settings_field( 'boj_myplugin_text_string', 'Enter text here',
		'boj_myplugin_setting_input', 'boj_myplugin', 'boj_myplugin_main' );
}
// Draw the section header
function boj_myplugin_section_text() {
	echo '<p>Enter your settings here.</p>';
}
// Display and fill the form field
function boj_myplugin_setting_input() {
	// get option 'text_string' value from the database
	$options = get_option( 'boj_myplugin_options' );
	$text_string = $options['text_string'];
	// echo the field
	echo "<input id='text_string' name='boj_myplugin_options[text_string]' type='text' value='$text_string'/>";
}
// Validate user input (we want text only)
function boj_myplugin_validate_options( $input ) {
	$valid = array();
	$valid['text_string'] = preg_replace(
		'/[^a-zA-Z]/',
		'',
		$input['text_string'] );
	if( $valid['text_string'] != $input['text_string'] ) {
		add_settings_error(
			'boj_myplugin_text_string',
			'boj_myplugin_texterror',
			'Incorrect value entered!',
			'error'
		);
	}
	return $valid;
}?>