ios - 如何只保留 UITextField 的下边框？

Question

有必要在 UITextField 处只保留底部边框。出于某种原因，我的代码不起作用。

let bottomLine = CALayer()
bottomLine.frame = CGRect(x:0.0, y:1.0, width: myTextField.frame.width, 
height: myTextField.frame.height - 1)
bottomLine.backgroundColor = UIColor.white.cgColor
myTextField.borderStyle = UITextBorderStyle.None
myTextField.layer.addSublayer(bottomLine)

Answer 1

替换这个

 bottomLine.frame = CGRect(x:0.0, y:1.0, width: myTextField.frame.width,height: myTextField.frame.height - 1)

与

bottomLine.frame = CGRect(x:0.0, y:myTextField.frame.height - 1, width: myTextField.frame.width,height: 1)