Question

I’m trying to use a Class_B function in one of Class_A’s functions. But a lot of Class_B’s functions include $this which causes problems. These are both classes (each class is of course in its own file):

class Class_A
{
   function hello()
   {
      require('class_b.php');
      echo 'Hello ' . Class_B::person();
   }

   function bye()
   {
      require('class_b.php');
      echo 'Bye ' . Class_B::person();
   }
}

class Class_B
{
   function person()
   {
      // various operations and variables
      echo $this->get_user($id);
   }
}

When I run the Class_A file I get Call to undefined method Class_A::person() in (...) because I think the $this value is changed when I instantiate the Class_A class. It overrules the Class_B value. How can I stop this?

Also, another question: how can I access Class_B from every function in Class_A? I don’t want to redeclare the class. Do I need to do this:

class Class_A
{
   function function1()
   {
      require('class_b.php');
      $class_b = new Class_B();
      // code
   }

   function function2()
   {
      require('class_b.php');
      $class_b = new Class_B();
      // code
   }
}

Or do I need to use a constructor or something?

Answer 1

By Class_B::person() you are calling the method statically. So you should declare the person() method as static and can’t use $this because you don’t have an instance of Class_B.

If you need an instance of Class_B, just create it and store in the class_B on construction.

class Class_A {
  private $b;
  function __construct()
  {
    $this->b = new Class_B();
  }     
  function stuff()
  {
    $this->b->person();
  }