Fatal error: Call to private MyObject::__construct() from invalid context

問題： 

When creating a new object in PHP, I get the following error message:

Fatal error: Call to private MyObject::__construct() from invalid context

I just create the new object and do not try to call the constructor explicitly. Does anyone know what's going on?

解釋：

Your

MyObject

class has a protected or private constructor, which means that the class cannot be instantiated.

__construct()

functions are always called when an object is instantiated, so trying to do something like

$x = new MyObject()

will cause a fatal error with a private construction function. (If you do not specifically declare a

__construct()

function, the parent constructor will be called).

Private constructors are often used in Singleton classes to prevent direct instantiation of an object. If it's not a class that you built, it might have a

getInstance()

function available (or something similar) to return an instance of itself.