Question

My Views expect certain variables to be defined by the controllers invoking them. As such, I created my own controller to extend from. This controller, in turn, extends CI_Controller.

class MainController extends CI_Controller{

static protected $data_bundle;

/**
All classes that will extend MainController should have their own constructors
calling the constructor of MainController.
*/
public function __construct(){
    parent::__construct();
    $data_bundle["title"] = "";
    $data_bundle["content"] = "";
    $data_bundle["stylesheets"] = array();
    $data_bundle["scripts"] = array();
    $data_bundle["echo_content"] = true;
}

}

So, for instance, I may define a Controller for a plain page as follows

class PlainPage extends MainController{
    public function __construct(){
        parent::__construct()
    }

    public function page(){
        parent::$data_bundle["title"] = "Plain Page"
        parent::$data_bundle["content"] = "The quick brown fox jumps over the lazy dog."
        $this->load->view("mainview", parent::$data_bundle);
    }
}

Then, in mainview.php, I have the following bit of code:

<?php
        foreach($stylesheets as $style){
            echo '<link rel="stylesheet" type="text/css" href="css/$style" />"';
        }
    ?>

    <?php
        foreach($scripts as $script){
            echo '<script type="text/javascript" src="scripts/$script"></script>"';
        }
    ?>

But I get the following errors:

Message: Undefined variable: {stylesheets|scripts}
Message: Invalid argument supplied for foreach()

Isn’t it that when parent::__construct() gets called, the $data_bundle array should’ve been initialized? Why is CI/PHP complaining that I have variables undefined?

Answer 1

You missed self in parent class constructor when initializing the static property.

public function __construct(){
    parent::__construct();
    self::$data_bundle["title"] = "";
    self::$data_bundle["content"] = "";
    self::$data_bundle["stylesheets"] = array();
    self::$data_bundle["scripts"] = array();
    self::$data_bundle["echo_content"] = true;
}

But You don’t need to use static property in this case, controller should have only one instance, so a instance property is enough.

class MainController extends CI_Controller{

protected $data_bundle = array();

/**
All classes that will extend MainController should have their own constructors
calling the constructor of MainController.
*/
public function __construct(){
    parent::__construct();
    $this->data_bundle["title"] = "";
    $this->data_bundle["content"] = "";
    $this->data_bundle["stylesheets"] = array();
    $this->data_bundle["scripts"] = array();
    $this->data_bundle["echo_content"] = true;
}

}

class PlainPage extends MainController{
    public function __construct(){
        parent::__construct()
    }

    public function page(){
        $this->data_bundle["title"] = "Plain Page"
        $this->data_bundle["content"] = "The quick brown fox jumps over the lazy dog."
        $this->load->view("mainview", $this->data_bundle);
    }
}