在IBDesignableTextField上设置颜色的位置

Question

我有一个问题，建议在哪里设置我已经子类化的UITextField的颜色。这是一些代码。

@IBDesignable
class TextField: UITextField {

     //var inset is not important for this question. 
     @IBInspectable var inset: CGFloat = 10

     override init(frame: CGRect) {
           super.init(frame: frame)
           //tried setting color here, didn't show up in storyboard
      } 

     required init?(coder aDecoder: NSCoder) {
          super.init(coder: aDecoder)
          //tried setting color here, didn't show up in storyboard
     }

     override func drawRect(rect: CGRect) {
          super.drawRect(rect)
          //tried setting color here, didn't show up in storyboard
     }

    override func textRectForBounds(bounds: CGRect) -> CGRect {
         self.backgroundColor = UIColor.redColor()
         //HERE IT WORKS!!!
         return CGRectInset(bounds, inset, inset)
    }

    override func editingRectForBounds(bounds: CGRect) -> CGRect {
         return textRectForBounds(bounds)
    }
}

所以，我基本上要做的是编写一个UITextField的子类，用于设置故事板中显示的文本字段（以及将来的其他内容）的背景颜色。我可以让它工作的唯一地方是textRectForBounds:函数，我必须为文本设置填充。我的问题是，建议在哪里设置UITextField的背景颜色，并在故事板中显示更改？感谢。