How can Omnipay be integrated with CodeIgniter?

I have previously utilized ci-merchant, but based on my research, it appears that ci-merchant's "V2" has transitioned into omnipay. As a user of CodeIgniter, I am currently facing difficulties in getting the provided example to function properly.

To address this issue, I have successfully installed omnipay without any complications. In my controller, I have implemented the following code:



use Omnipay\Common\GatewayFactory;

class Homepage extends BC_basecontroller {
    public function index() {
        $gateway = GatewayFactory::create('PayPal_Express');
        $gateway->setUsername('adrian');
        $gateway->setPassword('12345');
    }
}
This code snippet aligns with the example provided in the GitHub repository for omnipay, which can be found at https://github.com/adrianmacneil/omnipay.

However, upon execution, I encounter the following error:


PHP Fatal error: Class 'Omnipay\Common\GatewayFactory' not found in......
If anyone has any insights on how to resolve this issue and successfully integrate omnipay within the CodeIgniter framework, I would greatly appreciate your assistance.