//删除按钮
deleteButton = UIButton(frame: CGRect(x: 290, y: 80, width: 30, height: 20))
deleteButton.setTitle("X", for: .normal)
deleteButton.setTitle("Y", for: .selected)
deleteButton.backgroundColor = UIColor.lightGray
deleteButton.addTarget(self, action: #selector(deleteButtonClick), for: .touchUpInside)
提示错误:Use of unresolved identifier 'deleteButtonClick'
不写点击事件就可以运行
没有实现这个按钮的点击事件