无法将 Double 类型的值分配给 String

Question

尝试将标签文本分配给 2 个每个 textField 输入 警告显示说不能将 Double 类型的值分配给类型字符串

任何建议

    @IBAction func percentage1button(_ sender: Any) {
        
        let firstValue = Double(percentage1textField1.text!)
        let secondValue = Double(percentage1textfield2.text!)
       
        let outputValue = Double(firstValue! + secondValue!)
        percentage1result.text = outputValue
    }

Answer 1

我还建议您不要使用强制解包：

@IBAction func percentage1button(_ sender: Any) {
    guard let val1 = Double(percentage1textField1.text ?? ""),
          let val2 = Double(percentage1textfield2.text ?? "") else
    {
        return
    }
    let outputValue = val1 + val2
    percentage1result.text = "\(outputValue)"
}