source: trunk/www.guidonia.net/wp/wp-content/plugins/parteibuch-aggregator/pba-widgets.php@ 44

<?php

        //let's make some widgets
        //Thanks to brainfart for the lesson ;-)
        //http://brainfart.com.ua/post/lesson-wordpress-multi-widgets/

                add_action('init', 'pba_register_widgets');

function pba_register_widgets() {
        if(!function_exists('wp_register_sidebar_widget')) return false;

        $prefix = 'pba_itemtitles'; // $id prefix
        $name = __('RSS Aggregator');
        $widget_ops = array('classname' => 'widget_name_multi', 'description' => __('Add item titles of your aggregated feeds to your blog&#39;s sidebar'));
        $control_ops = array('width' => 200, 'height' => 200, 'id_base' => $prefix);
 
        $options = get_option('widget_name_multi');
        if(isset($options[0])) unset($options[0]);
 
        if(!empty($options)){
                foreach(array_keys($options) as $widget_number){
                        wp_register_sidebar_widget($prefix.'-'.$widget_number, $name, 'widget_name_multi', $widget_ops, array( 'number' => $widget_number ));
                        wp_register_widget_control($prefix.'-'.$widget_number, $name, 'widget_name_multi_control', $control_ops, array( 'number' => $widget_number ));
                }
        } else{
                $options = array();
                $widget_number = 1;
                wp_register_sidebar_widget($prefix.'-'.$widget_number, $name, 'widget_name_multi', $widget_ops, array( 'number' => $widget_number ));
                wp_register_widget_control($prefix.'-'.$widget_number, $name, 'widget_name_multi_control', $control_ops, array( 'number' => $widget_number ));
        }
}

function widget_name_multi($args) {
        if(!function_exists('wp_register_sidebar_widget')) return false;
                $prefix = 'pba_itemtitles'; // $id prefix
    extract($args);
                $options = get_option('widget_name_multi');

//    echo "<br>See the calling arguments for the widget with id " . $widget_id . ":<br>";
//    print_r($args);
//    echo "<br>See all the saved options:";
//    print_r($options);

                if(preg_match('/'.$prefix.'-([0-9]+)/i', $widget_id, $match)){
                        $widget_number = $match[1];
                        //echo "<br>Fine, this is our widget number " . $widget_number;
                        if(isset($options[$widget_number])){
                                $pba_option_set=$options[$widget_number];
//                              echo "<br>Great, we have an option set, which we can use as input parameter to our stuff: ";
                                //print_r($pba_option_set);
                                echo $before_widget; echo $before_title; 
                                if(isset($pba_option_set['title'])) echo $pba_option_set['title'];
                                echo $after_title;
                                if(isset($pba_option_set['pba_outputid'])) {
                                        //echo "Output ID: " . $pba_option_set['pba_outputid'];
                                        $pba_config['outputid']=$pba_option_set['pba_outputid'];
                                        $pba_config['show_sidebarwidget'] = 'Y';
                                        $pba_return=@PBA::outputwrapper($pba_config);
                                        echo $pba_return["result"];
                                }
                                echo $after_widget;
                        }
                }
 }

function widget_name_multi_control($args) {
        if(!function_exists('wp_register_sidebar_widget')) return false;

        $prefix = 'pba_itemtitles'; // $id prefix
 
        $options = get_option('widget_name_multi');
        if(empty($options)) $options = array();
        if(isset($options[0])) unset($options[0]);
 
        // update options array
        if(!empty($_POST[$prefix]) && is_array($_POST)){
                foreach($_POST[$prefix] as $widget_number => $values){
                        if(empty($values) && isset($options[$widget_number])) // user clicked cancel
                                continue;
 
                        if(!isset($options[$widget_number]) && $args['number'] == -1){
                                $args['number'] = $widget_number;
                                $options['last_number'] = $widget_number;
                        }
                        $options[$widget_number] = $values;
                }
 
                // update number
                if($args['number'] == -1 && !empty($options['last_number'])){
                        $args['number'] = $options['last_number'];
                }
 
                // clear unused options and update options in DB. return actual options array
                $options = bf_smart_multiwidget_update($prefix, $options, $_POST[$prefix], $_POST['sidebar'], 'widget_name_multi');
        }
 
        // $number - is dynamic number for multi widget, gived by WP
        // by default $number = -1 (if no widgets activated). In this case we should use %i% for inputs
        //   to allow WP generate number automatically
        $number = ($args['number'] == -1)? '%i%' : $args['number'];
 
        // now we can output control
        $opts = @$options[$number];
 
        $title = @$opts['title'];
 
  echo 'Please enter a name for your widget:<br />'; 
        echo '<input type="text" ' . 
                'name="' . $prefix . '[' . $number . '][title]" ' . 
                'value="' . $title . '" /><br /><br />';

        global $bdprss_db;
        $pba_output_streams=$bdprss_db->get_all_pbaoutputs();
        if($pba_output_streams) {
                //print_r($pba_output_streams);
                echo 'Please select an output stream:<br />'; 
                echo '<select name="' . $prefix . '[' . $number . '][pba_outputid]">';
                $didselect=false;
                foreach($pba_output_streams as $pbaosnr => $pba_os_object){
                        $selected="";
                        if($pba_os_object->identifier == @$opts['pba_outputid']) {
                                $selected=" selected ";
                                $didselect=true;
                        }
                        if(($pbaosnr + 1) == count($pba_output_streams) && !$didselect) $selected=" selected ";
                        echo '<option value="'.$pba_os_object->identifier.'"'.$selected.' >ID: '.$pba_os_object->identifier.'&nbsp;-&nbsp;'.$pba_os_object->name.'&nbsp;</option>' . "\n";
                }
                echo '</select>';
        }else{
                echo 'Parteibuch Aggregator could not detect any output format to show in this widget. 
                        You need to <a href="edit.php?page=parteibuch-aggregator/bdp-rssadmin.php&action=createpbaoutput">create an output format</a> first.';
        }
}

// helper function can be defined in another plugin
if(!function_exists('bf_smart_multiwidget_update')){
        function bf_smart_multiwidget_update($id_prefix, $options, $post, $sidebar, $option_name = ''){
                global $wp_registered_widgets;
                static $updated = false;
 
                // get active sidebar
                $sidebars_widgets = wp_get_sidebars_widgets();
                if ( isset($sidebars_widgets[$sidebar]) )
                        $this_sidebar =& $sidebars_widgets[$sidebar];
                else
                        $this_sidebar = array();
 
                // search unused options
                foreach ( $this_sidebar as $_widget_id ) {
                        if(preg_match('/'.$id_prefix.'-([0-9]+)/i', $_widget_id, $match)){
                                $widget_number = $match[1];
 
                                // $_POST['widget-id'] contain current widgets set for current sidebar
                                // $this_sidebar is not updated yet, so we can determine which was deleted
                                if(!in_array($match[0], $_POST['widget-id'])){
                                        unset($options[$widget_number]);
                                }
                        }
                }
 
                // update database
                if(!empty($option_name)){
                        update_option($option_name, $options);
                        $updated = true;
                }
 
                // return updated array
                return $options;
        }
}

?>