swift - TextField 未更新，给我可选的 ""

Question

我试图在调用函数时获取文本字段来更新其标签。 当我调用它时，我得到可选“”的返回，并且文本字段变为空白。下面是我的代码..

func P18Switch() {

        if metricImperialSwitch?.selectedSegmentIndex == 0
        {
            measurementSwitch = 0
            CWLabel.text = "kg"; TWLabel.text = "kg"; CWaLabel.text = "cm"; TWaLabel.text = "cm"; CHLabel.text = "cm"; THLabel.text = "cm"


            if CWeight.text == "" {
                print("No go")
        } else {

//                 b = 0.453592
//                 c =  Double
//                 d = Double(CWeight.text!)

                c = d! * b

                CWeight.text = c as? String
                print(CWeight.text)
            }
        }

我之前声明了 b、c 和 d

Answer 1

不要将 Double 转换为 String，只需执行以下操作:

CWeight.text = String(c)