iOS UITextField在swift中强调样式

Question

我已添加此图片，希望您能看到它，用户界面登录。请注意，文本字段是透明的，但底部的行除外。我用什么代码来获得这种影响？我可以将必要的信息放在“用户定义的运行时属性”中吗？

Answer 1

创建UITextField的子类，如下所示，只需在故事板中将此类设置为UItextField

使用@IBInspectable支持Swift 4.2

import UIKit

class HSUnderLineTextField: UITextField , UITextFieldDelegate {

    let border = CALayer()

    @IBInspectable open var lineColor : UIColor = UIColor.black {
        didSet{
            border.borderColor = lineColor.cgColor
        }
    }

    @IBInspectable open var selectedLineColor : UIColor = UIColor.black {
        didSet{
        }
    }


    @IBInspectable open var lineHeight : CGFloat = CGFloat(1.0) {
        didSet{
            border.frame = CGRect(x: 0, y: self.frame.size.height - lineHeight, width:  self.frame.size.width, height: self.frame.size.height)
        }
    }

    required init?(coder aDecoder: (NSCoder?)) {
        super.init(coder: aDecoder!)
        self.delegate=self;
        border.borderColor = lineColor.cgColor
        self.attributedPlaceholder = NSAttributedString(string: self.placeholder ?? "",
                                                               attributes: [NSAttributedString.Key.foregroundColor: UIColor.white])


        border.frame = CGRect(x: 0, y: self.frame.size.height - lineHeight, width:  self.frame.size.width, height: self.frame.size.height)
        border.borderWidth = lineHeight
        self.layer.addSublayer(border)
        self.layer.masksToBounds = true
    }

    override func draw(_ rect: CGRect) {
        border.frame = CGRect(x: 0, y: self.frame.size.height - lineHeight, width:  self.frame.size.width, height: self.frame.size.height)
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        border.frame = CGRect(x: 0, y: self.frame.size.height - lineHeight, width:  self.frame.size.width, height: self.frame.size.height)
        self.delegate = self
    }

    func textFieldDidBeginEditing(_ textField: UITextField) {
        border.borderColor = selectedLineColor.cgColor
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        border.borderColor = lineColor.cgColor
    }
}

使用情节提要设置属性。请在下面找到截图供参考。