Swift 3-在方向更改时翻转整个屏幕/视图

Question

I need to a way to constantly monitor if the user has rotated the iPad.

UserDidRotate() {

    if(orientation = portrait.upsideDown){

        //
        //Code that will Present View upside down...
        //
    }
        else if(orientation = portrait){

        //
        //Code that will Present View right side up...
        //
    }
}

How can I check for orientation change and also manually present the view upside down for my Swift 3 app?

EDIT:

I have tried:

override func viewWillTransition(to size: CGSize, with coordinator: 
UIViewControllerTransitionCoordinator){} 

and that method is never hit.

Answer 1

尝试：

self.view.transform = self.view.transform.rotated(by: CGFloat(M_PI))