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Coming from a strong background in ActionScript 3, the process of requiring/importing a class that will be referenced / used / extended in another class is as follows:
import package.inner.ClassName;
This is required at the top of every external class file that will make use of ClassName, meaning it's required if I do any of the following, for example:
public class NewClass extends ClassNamevar someVar:ClassName = new ClassName();function someMethod():ClassName{ .. }etc
I've got a fair bit of knowledge with PHP, ie I know how to use it to work with MySQL, output text, write functions, set up some basic classes, etc.
I've always just had one main class for small websites, which I create an instance of on the web-page at the top and work with from there, eg:
<?php
class Website
{
public function __construct()
{
// connect to mysql, etc
}
public function example()
{
echo "example text";
}
}
?>
And then:
<?php
require "whatever/class.website.php";
$website = new Website();
?>
<!doctype html>
<html>
<head>
<title>Example</title>
</head>
<body>
<?php
$website->example();
?>
</body>
</html>
This is fine, but now I want to start moving onto some larger projects with multiple classes. At first I was going OK, but after trying to set up a base class for multiple classes, I've run into a problem:
As an example, I've set up the following base class:
class Base
{
public function test($input)
{
echo $input;
}
}
From there I set up a class that extends this:
require "class.base.php";
class ExampleOne extends Base
{
public function __construct()
{
$this->test("example one");
}
}
And then checked to see if all worked as expected, which it did:
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
</head>
<body>
<?php
require "class.exampleone.php";
$one = new ExampleOne();
?>
</body>
</html>
I then went on to create an additional class that extends Base, which is where I ran into problems..
require "class.base.php";
class ExampleTwo extends Base
{
public function __construct()
{
$this->test("example two");
}
}
When I tried to create an instance of this class, or even just use require to gain access to the class, I get an error:
Fatal error: Cannot redeclare class Base in C:\xampp\htdocs\testing\class.base.php on line 3
So admittedly this error is pretty self explanatory, it's because I've used require "class.base.php"; at the top of each class - which is what you would do in ActionScript 3 because I'm making use of the base class (extending it).
I guess I'm just finding it hard to understand how I should be doing this. Where should I be putting my require for Base? It seems strange to omit it in the latter class I've extended, because if I don't make an instance of my first class then the base class won't be included at all.
Any advice would be awesome!
412
You can use the require_once() statement. It functions just like the require statement, but will check to make sure that the base class hasn't been included yet and will load it if needed.
http://php.net/manual/en/function.require-once.php
You may also want to look into web frameworks depending on the size of your website, but that's outside of the question scope :)
75
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