直接上代码

class ShareViewController: UIViewController {
    
    class var shareDistance:ShareViewController  {
        
        struct shareDistance{
            static var shareVC:ShareViewController? = nil
            static var Once:dispatch_once_t  = 0
        }
        
        dispatch_once(&shareDistance.Once) { () -> Void in
            if shareDistance.shareVC == nil{
                //从storyboard上创建vc
                let shareVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("ShareViewController")
                shareDistance.shareVC = shareVC as? ShareViewController
            }
        }
    
        return shareDistance.shareVC!
    }
    
}

storyBoard 设置如下图

Paste_Image.png