swift dispatch_after

在swift中,使用GCD的延迟执行,需要自己写一些参数,代码如下:

        let delay = 3.0 * Double(NSEC_PER_SEC)
                    let when = DispatchTime.now()+delay
                    DispatchQueue.main.asyncAfter(deadline: when, execute: { 
                        _ = self.navigationController?.popViewController(animated: true)
                    })

29. Mar 17更新