警告：尝试访问 C 中 null 类型值的数组偏移量：

Question

Hi I have been working all this week on this project that I'm helping my son with for his school project, the project is a PHP login script using the MVC design everything runs but I keep getting the following Warning: Trying to access array offset on value of type null in C:\wamp64\www\mvcloginregister\app\libraries\Core.php on line 18, line 18 is the following code:

// Look in BLL for first value
 18 if(file_exists('../app/controllers/' . ucwords($url[0]). '.php')){
    // If exists, set as controller
    $this->currentController = ucwords($url[0]);
    // Unset 0 Index
    unset($url[0]);
  }
I think the issue is in the following function 
public function getUrl(){
  if(isset($_GET['url'])){
    $url = rtrim($_GET['url'], '/');
    $url = filter_var($url, FILTER_SANITIZE_URL);
    $url = explode('/', $url);
    return $url;
  }
}

I have reviewed all recommended answer related to this issue on this site and I'm unable to fix this issue I also found a post on google with the same issue but the person who fixed the issue did not post the solution which I think is rude and unprofessional. Please help I'm very new to this php language and the MVC design.

Answer 1

Today I had the same problem and also couldn't find any solution around the web. Finally I've solved it by myself: added the $url variable to the condition inside the "if" statement. this checks not only if the file exists but also if $url isn't null - like so:

 $url = $this->getUrl();
 
  if( $url && file_exists('../app/controllers/' . ucwords($url[0]). '.php') ){
   
    $this->currentController = ucwords($url[0]);
    
    unset($url[0]);
  }