单击设置为在 xcode 中隐藏的按钮会在模拟器中留下一条细线，然后隐藏

Question

我是swift的新手，所以有点难以弄清楚发生了什么。下面是我的代码片段。我还附上了一些图片，展示了我点击按钮后的样子。任何帮助都将不胜感激。非常感谢。

@IBOutlet weak var btnOptionOne: UIButton!
@IBOutlet weak var btnOptionTwo: UIButton!
@IBOutlet weak var btnOptionThree: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
backgroundColor = view.backgroundColor
// Do any additional setup after loading the view, typically from a nib.
card.layer.cornerRadius = 20.0
frontLabel.layer.cornerRadius = 20.0
backLabel.layer.cornerRadius = 20.0
btnOptionOne.layer.cornerRadius = 20.0
btnOptionOne.layer.borderColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 1)
btnOptionOne.layer.borderWidth = 3.0
btnOptionTwo.layer.cornerRadius = 20.0
btnOptionTwo.layer.borderColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 1)
btnOptionTwo.layer.borderWidth = 3.0
btnOptionThree.layer.cornerRadius = 20.0
btnOptionThree.layer.borderColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 1)
btnOptionThree.layer.borderWidth = 3.0
card.layer.shadowRadius = 15.0
frontLabel.layer.shadowRadius = 15.0
backLabel.layer.shadowRadius = 15.0
card.layer.shadowOpacity = 0.2
frontLabel.layer.shadowOpacity = 0.2
backLabel.layer.shadowOpacity = 0.2
frontLabel.clipsToBounds = true
backLabel.clipsToBounds = true
}

@IBAction func didTapOnFlashcard(_ sender: Any) {
if frontLabel.isHidden == true{
frontLabel.isHidden = false;
}
else{
frontLabel.isHidden = true;
}
}
@IBAction func didTapOptionOne(_ sender: Any) {
btnOptionOne.isHidden = true
}

点击第一个选项之前

点击第一个选项后

Answer 1

点击移除阴影时：-

btnOptionOne.layer.shadowOpacity = 0
btnOptionOne.layer.shadowRadius = 0
btnOptionOne.layer.shadowColor = nil