Error handling PHP function - php

Question

So I want to make a function to display errors instead of saying echo "error message", I want something like $this->errorDisplay('error message');
I currently have this, but it's not doing the job.
function errorDisplay($msg) {
$this->errors[] = $msg;
foreach($this->errors as $error) {
echo $error;
}
}
public function checkFields($username,$password) {
if(!empty($username) && !empty($password)) {
//proceed to validation
} else {
$this->errorDisplay('All fields are required.');
}
}

Answer 1

Instead of trying to do everything in one method, split the process into 2. One method adds messages to an array, and the other shows all the previously saved up messages.
Class xxx
{
public $errors = array();
public function addError($msg) {
$this->errors[] = $msg;
}
public function showErrors() {
foreach($this->errors as $error) {
echo $error;
}
}
public function initErrors() {
$this->errors = array();
}
public function checkFields($username,$password) {
$this->initErrors();
if( empty($username) ) {
$this-addError('Username missing');
}
if ( empty($password) ) {
$this-addError('Password missing');
}
if ( count($this->errors) > 0 ) {
$this->showErrors();
}
}
} //end class