PHP - Change value of property throughout class

Question

I have two functions within my class and need to use information from one to make a decision in the other. I though I could change the value of a property just like it works in Javascript functions by just setting it equal to a new value, but that's a big misunderstanding. How can I change the value of a property throughout a class?

class Show_Or_Not {

    public $num;

    public function __construct() {

     add_action( 'woocommerce_cart_calculate_fees', array( $this, 'check_cart_for_condition'), 50 );
     add_filter( 'wc_add_to_cart_message', array( $this, 'use_the_cart_condition'), 100, 2 );

    }

    public function check_cart_for_condition() {

      // Ton of code checking how often a certain category occurs in the cart.

      if ( $cat_in_cart == 1 ) {
          // Trying to update value of class property in 
          // order to use it in the next function.
          $this->num = 1;
      } elseif ( $cat_in_cart == 2 ) {
          // Trying to update value of class property in 
          // order to use it in the next function.
          $this->num = 2;
      }

    }

    public function use_the_cart_condition() {

      // If condition determined in upper function is met. 
      if ( $this->num == 1 ) {
         // Do something
      } elseif ( $this->num == 2 ) {
         // Do something
      }

    }

}

$newClass = new Show_Or_Not();

Showing the class definition is a good start, but could you also please post some example code showing how you want to instantiate and use this class? — John McMahon
– John McMahon, Commented Apr 22, 2015 at 1:08
Seems that you have to pass a parameter in set_the_condition(), something like set_the_condition($condition ) — Marcio Mazzucato
– Marcio Mazzucato, Commented Apr 22, 2015 at 1:08
Where's the rest of your code? How are you calling the methods? — Ja͢ck
– Ja͢ck, Commented Apr 22, 2015 at 1:21
@Ja͢ck I've updated the context. The point is that I can't both set and use the condition in the same function (using WordPress actions and filters), that's why I though It could use a class property to do this. My question is more PHP than WordPress related though, just pointing out that I'm trying to update a property to use it further down. — piggypig
– piggypig, Commented Apr 22, 2015 at 1:32
I guess it depends on which method is called first; how about, inside use_the_cart_condition() you always call $this->check_cart_for_condition();? — Ja͢ck
– Ja͢ck, Commented Apr 22, 2015 at 2:05

Cody Christofferson · Accepted Answer · 2015-04-22 02:39:07Z

2

When you call an action or a filter, the second value needs to be the name of a method that can be found in your theme's functions.php file. You can add custom methods to the file.

// In the functions.php file for the theme

function check_cart_for_condition() {
     // get the session
     global $session;

    // initialize the $num var
    $num = 0;
    // Ton of code checking how often a certain category occurs in the cart.
    if ( $cat_in_cart == 1 ) {
        // Trying to update value of class property in 
        // order to use it in the next function.
        $num = 1;
     } elseif ( $cat_in_cart == 2 ) {
        // Trying to update value of class property in 
        // order to use it in the next function.
        $num = 2;
    }

    // This only needs to be for the next request since the hooks
    // run back to back, add it to the session flash data
    $session->set_flashdata( 'num', $num );
}


public function use_the_cart_condition() {
     global $session;
     // Retrieve Flashdata
     $num = $session->flashdata( 'num' );

    // If condition determined in upper function is met. 
    if ( $this->num == 1 ) {
       // Do something
    } elseif ( $this->num == 2 ) {
       // Do something
    }
}

Now just add this to your code where you need it:

 add_action( 'woocommerce_cart_calculate_fees','check_cart_for_condition', 50 );
 add_filter( 'wc_add_to_cart_message','use_the_cart_condition', 100, 2 );

edited Apr 22, 2015 at 2:39

answered Apr 22, 2015 at 1:18

Cody Christofferson

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6 Comments

piggypig Over a year ago

Thanks for you reply, my bad I missed that. I'll provide more context to the issue right now. It's not that I'm experiencing a fatal error.

Ja͢ck Over a year ago

I've taken the liberty to tidy up the first part of your answer ;-)

Cody Christofferson Over a year ago

Thanks Jack. I had considered making it one section but figured I'd try to be as verbose as possible.

Cody Christofferson Over a year ago

Ok, so, going to modify my answer, but what I think you are trying to achieve within a class isn't possible. I could be wrong, but I will explain in my answer.

piggypig Over a year ago

Thanks! This is an approach that works. WordPress does not support $session, but WooCommerce does happen to have to ability to set and get session data using WC()->session->set/get.

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