PHP classses/functions

How do I get the $str variable (below) into my class/classes? The function is used to call each class dynamically rather tan have "lots" of if(class_exists) statements.

on page:

echo rh_widget('Search');

the function (on functions page):

function rh_widget($str) {
global $db, $table_prefix;
$newwidget = 'rh_'.strtolower($str);
    if(class_exists($newwidget)):
    $rh_wid = new $newwidget(); 
    echo $rh_wid->rh_widget;
    endif;

}

Then a Parent & child class (on classes page) such as:

class widget {
public $str;
function __construct() {
$this->before_widget .= '<ul class="rh_widget">';
$this->before_title .= '<li><h3>'.$str.'';
$this->after_title .= '</h3><ul>';
$this->after_widget .= '</ul></li></ul>';
}

}

class rh_search extends widget {
public function __construct() {
parent::__construct();
global $db, $table_prefix;
    $this->rh_widget .= $this->before_widget;
    $this->rh_widget .= $this->before_title.' '.$this->after_title; 
    $this->rh_widget .= '<li>Conte开发者_C百科nt etc. in here</li>';
    $this->rh_widget .= $this->after_widget;    

} }

What I cannot get to happen is to "pull" $str through from the function call through function to the class.

Any suggestion please. Thanks

---

I think you are trying to get access to the variable $str from the class widget; correct me if this is not the case.

You need to pass the variable as an argument to the constructor:

class widget {
    public $str;
    function __construct($str) { // add $str as an argument to the constructor
        $this->before_widget .= '<ul class="rh_widget">';
        $this->before_title .= '<li><h3>'.$str.'';
        $this->after_title .= '</h3><ul>';
        $this->after_widget .= '</ul></li></ul>';
    }
}

class rh_search extends widget {
    public function __construct($str) { // add $str to the constructor
        parent::__construct($str); // pass $str to the parent
        global $db, $table_prefix;
        $this->rh_widget .= $this->before_widget;
        $this->rh_widget .= $this->before_title.' '.$this->after_title; 
        $this->rh_widget .= '<li>Content etc. in here</li>';
        $this->rh_widget .= $this->after_widget;    
    }
}

function rh_widget($str) {
    global $db, $table_prefix;
    $newwidget = 'rh_'.strtolower($str);
    if(class_exists($newwidget)):
        $rh_wid = new $newwidget($str); // pass $str to the constructor
        echo $rh_wid->rh_widget;
    endif;
}