Underlined UITextView in Swift

UnderlinedTextField.swift

//
//  UnderlinedTextField.swift
//  Assembly
//
//  Created by Jose Antonio Lopez (jalopezsuarez@gmail.com) on 01/01/17.
//  Copyright (c) 2017 Vemovi Desarrolla sl. All rights reserved.
//

import Foundation

@IBDesignable
class UnderlinedTextField : UITextField, UITextFieldDelegate {
    
    @IBInspectable var hintTextColor : UIColor?
    
    @IBOutlet weak var nextField : UITextField?
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        self.delegate = self
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        self.delegate = self
    }
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        
        let lineLayer = CALayer()
        lineLayer.frame = CGRect(x: 0, y: rect.size.height-1, width: rect.size.width, height: 1)
        lineLayer.backgroundColor = UIColor.white.cgColor
        
        layer.addSublayer(lineLayer)
    }
    
    override func drawPlaceholder(in rect: CGRect) {
        let color = (hintTextColor ?? textColor)!
        
        let placeholderAttr : [NSAttributedStringKey : AnyObject] = [NSAttributedStringKey(rawValue: NSAttributedStringKey.foregroundColor.rawValue): color, NSAttributedStringKey(rawValue: NSAttributedStringKey.font.rawValue) : font!]
        let placeholderTextSize = placeholder!.size(withAttributes: placeholderAttr)
        let placeholderRect = CGRect(x: 0, y: abs(rect.size.height - placeholderTextSize.height) / 2, width: placeholderTextSize.width, height: placeholderTextSize.height)
        
        NSString(string: placeholder!).draw(in: placeholderRect, withAttributes: placeholderAttr)
    }
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        
        if nextField != nil {
            nextField!.becomeFirstResponder()
        } else {
            resignFirstResponder()
        }
        
        return false
    }
}