How to call a function from one module to another Magento 2 - magento2

Question

I try to call a function from a module A to a module B
here is the module A code
namespace A\Epayment\Model;
class Etransactions
{
public function customPayment{
return "test";
}
and module b code
namespace B\Payment\Controller\Index;
class Payment extends \Magento\Framework\App\Action\Action
{
protected $_pageFactory;
protected $_transaction;
public function __construct(
\Magento\Framework\App\Action\Context $context,
\Magento\Framework\View\Result\PageFactory $pageFactory,
\ETransactions\Epayment\Model\Etransactions $transaction
)
{
$this->_pageFactory = $pageFactory;
$this->_transaction = $transaction;
parent::__construct($context);
}
public function execute()
{
echo "Hello World".PHP_EOL;
$foo="a";
echo $foo;
echo $this->_transaction->customPayment();
//echo $this->customPayment();
echo $foo;
exit;
}
}
this code return the "hello world", the first $foo, not the second and doesn't display any error
can someone explain me where is my error ?
EDIT: i didn't change anything but it works fine now.
thanks for the answers anyway

Answer 1

The object you want create the path your are injecting is incorrect.
public function __construct(
\Magento\Framework\App\Action\Context $context,
\Magento\Framework\View\Result\PageFactory $pageFactory,
\A\Epayment\Model\Etransactions $transaction // changes are here
)
{
$this->_pageFactory = $pageFactory;
$this->_transaction = $transaction;
parent::__construct($context);
}
Kindly use exception handling.
try{
$this->_transaction->customPayment();
}catch(Exception $e){
//log your exception here.
}

Answer 2

In Magento, Helper classes are available to use anywhere (Block, Controller, Model, Observer, View). So you should create a method in helper class and call it anywhere by the following way.
Declar the helper class and method: ModuleA\Epayment\Helper\Data.
<?php
namespace ModuleA\Epayment\Helper;
class Data extends \Magento\Framework\App\Helper\AbstractHelper
{
public function yourHelperMethod()
{
# code...
}
}
Call the method:
$helper = $this->_objectManager->create(ModuleA\Epayment\Helper\Data::class);
$helper->yourHelperMethod();
Note: If the object manager is not injected in your class. Please follow the steps below:
1) declare private property:
private $_objectManager;
2) inject in the constructor to initialize:
public function __construct(
\Magento\Framework\ObjectManagerInterface $objectmanager
) {
$this->_objectManager = $objectmanager;
}
3) use in some method:
public function someMethod() {
$helper = $this->_objectManager->create(ModuleA\Epayment\Helper\Data::class);
$helper->yourHelperMethod();
}