PHP OOP5 - 无法通过方法向对象添加上下文

Question

i got this class:

class Trajectory{
    private $points = array();

    public function __construct(){
    }

    public function addPoint(Point $myPoint){
        $this->points[] = $myPoint; // line 20
    }
}

when i try to run the method addPoint(), I'm getthing this error:

( ! ) Fatal error: Using $this when not in object context in /index.php on line 20

I tried changing it to:

$points[] = $myPoint;

but then the Trajectory's $point array doesn't change, instead its creating a new $points array each time i use the addPoint method.

Answer 1

You could not call this method as static method.

You should call it on an instance of the Class.

$trajectory = new Trajectory();
$trajectory->addPoint($point);

Instead of Trajectory::addPoint($point);