Php variable visibility [требует правки]

I have a Class for render views

class View {
    function render(){}
}

And another one for routing

$router->get("/", function(){})

I need to call render() function inside the router callback function, but when $view = new View defined outside, it doesnt work, and variable invisible inside the body of the callback function. Only when $view defined in body itself. If function render() written without class it also work. Any suggestions?