在Ios中创建仅包含底线的文本字段

Question

是否可以在Ios中创建一个Textfield，它只显示底部边框线而不显示上边线和侧边线。如果是，我该如何实现这个

Answer 1

是的，这是可能的。以下是如何做到这一点：

CALayer *border = [CALayer layer];
CGFloat borderWidth = 2;
border.borderColor = [UIColor darkGrayColor].CGColor;
border.frame = CGRectMake(0, textField.frame.size.height - borderWidth, textField.frame.size.width, textField.frame.size.height);
border.borderWidth = borderWidth;
[textField.layer addSublayer:border];
textField.layer.masksToBounds = YES;

希望这会有所帮助!!

Answer 2

针对Swift 3.0进行了更新

extension UITextField {    

    func useUnderline() {
        let border = CALayer()
        let borderWidth = CGFloat(1.0)
        border.borderColor = UIColor.lightGray.cgColor
        border.frame = CGRect(origin: CGPoint(x: 0,y :self.frame.size.height - borderWidth), size: CGSize(width: self.frame.size.width, height: self.frame.size.height))
        border.borderWidth = borderWidth
        self.layer.addSublayer(border)
        self.layer.masksToBounds = true
    }
}

Answer 3

夫特：

extension UITextField {

    func useUnderline() {

        let border = CALayer()
        let borderWidth = CGFloat(1.0)
        border.borderColor = UIColor.blackColor().CGColor
        border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, self.frame.size.height)
        border.borderWidth = borderWidth
        self.layer.addSublayer(border)
        self.layer.masksToBounds = true
    }
}

这样称呼：

yourtextFieldName.useUnderline()

Answer 4

只需将CALayer用于文本字段，只有Ios中的底线

CALayer *bottomBorder = [CALayer layer];
bottomBorder.frame = CGRectMake(0.0f, self.passwordField.frame.size.height - 1, self.passwordField.frame.size.width, 1.0f);
bottomBorder.backgroundColor = [UIColor blackColor].CGColor;
[self.passwordField.layer addSublayer:bottomBorder];

Answer 5

我正在使用Swift 4.2，并且在上述所有解决方案中，不同的设备存在问题。 iPhone X：

和Iphone XR：

有人有更好的解决方案吗？ 预先感谢

Answer 6

User4645956在Swift中的解决方案

private func addBottomLineToTextField(textField : UITextField) {
    let border = CALayer()
    let borderWidth = CGFloat(1.0)
    border.borderColor = UIColor.whiteColor().CGColor
    border.frame = CGRectMake(0, textField.frame.size.height - borderWidth, textField.frame.size.width, textField.frame.size.height)
    border.borderWidth = borderWidth
    textField.layer.addSublayer(border)
    textField.layer.masksToBounds = true
}

用法：

    self.addBottomLineToTextField(usernameTextField)
    self.addBottomLineToTextField(passwordTextField)