let codedLabel:UILabel = UILabel()
codedLabel.frame = CGRect(x: 100, y: 100, width: 200, height: 200)
codedLabel.textAlignment = .center
codedLabel.text = "b"
codedLabel.numberOfLines=1
codedLabel.textColor=UIColor.red
codedLabel.font=UIFont.systemFont(ofSize: 22)
codedLabel.backgroundColor=UIColor.lightGray
back_?.addSubview(codedLabel)
codedLabel.translatesAutoresizingMaskIntoConstraints = false
codedLabel.heightAnchor.constraint(equalToConstant: 200).isActive = true
codedLabel.widthAnchor.constraint(equalToConstant: 200).isActive = true
codedLabel.centerXAnchor.constraint(equalTo: codedLabel.superview!.centerXAnchor).isActive = true
codedLabel.centerYAnchor.constraint(equalTo: codedLabel.superview!.centerYAnchor).isActive = true