利用GCD和UILabel實現，代碼如下

//設置登錄成功提示

let label = UILabel.init(frame: CGRect.init(x: 50, y: 667 - 30 - 64 - 64, width: 375 - 100, height: 20))

label.text = "登錄成功"

label.font = UIFont.systemFont(ofSize: 15)

label.backgroundColor = UIColor.gray

label.textAlignment = .center

label.layer.cornerRadius = 4

label.layer.masksToBounds = true

mtvc.view.addSubview(label)

DispatchQueue.global().async {

Thread.sleep(forTimeInterval: 2)//延時2秒執行

//回到主線程

DispatchQueue.main.async {

label.removeFromSuperview()

}

}

_ = self.navigationController?.popToViewController(mtvc, animated: true)