Question

Following the advice in this posting: php class as a plugin in wordpress

I’ve created a helper class for use with other plugins. In the class file, I have a declaration for activating the class, like:

function test_init() {

    $test = new Test();

} // End of test_init()

I’m able to access the functions in this class by doing something like:

Test::my_function();

However, I’m having issues referring to functions within this class from each other. For example:

function my_function() {

    Test::other_func();

}

In a case like this, I get the error message: “Function name must be a string”

I’ve tried $this->other_func, which returns the error: “there is not function “other_func” in the Class_Using_The_Test_Class.

I’ve tried self::other_func, which return the error: “Function name must be a string”

I tried using call_user_func() and I get: “call_user_func() expects parameter 1 to be a valid callback”

How do I call another function within this class?

Answer 1

You don’t actually need to activate the class. I’ll give an example.

Let’s say this code lives in helper-class.php:

<?php

class Helper_Class {

    // Note: those are double underscores before the word 'construct'.
    function __construct() {

        // initialize/call things here.
        $this->init(); // this is how you call class functions.
    }

    function init() {
        // do some monkey-business

        return;
    }

    // we'll call this function from our other class.
    function some_function() {
        // do the fancy whizbang.
    }
}

?>

Now, over in your other class file you could have something like this:

<?php

// give ourselves access to the helper class.
require_once 'helper-class.php';

class Main_Class {

    // Note: those are double underscores before the word 'construct'.
    function __construct() {
        $this->init();
    }

    function init() {
        // classes can't be used until an object of that class is created.
        $helper_class_object = new Helper_Class;

        // now I can call functions in my helper class.
        $helper_class_object->some_function();

        return;
    }

}

?>

I hope this sheds a bit of light on your situation. Just ask if you’d like further clarification. 🙂