如何将textField.text值转换为Integer并将两个整数相加

Question

永远不会使用不可变值'textfieldInt'的初始化; 考虑将赋值替换为'_'或删除它和textfield2Int

我为textfieldInt收到两次警告

这是我的所有代码:

class ViewController: UIViewController {

    @IBOutlet weak var textField1: UITextField!
    @IBOutlet weak var textField2: UITextField!
    @IBOutlet weak var output: UILabel!

    @IBAction func calculate(_ sender: AnyObject) {
        let textfieldInt: Int? = Int(textField1.text!)
        let textfield2Int: Int? = Int(textField2.text!)
        let convert = textField1.text! + textField2.text!
        let convertText = String(convert)
        output.text = convertText

}

Answer 1

您收到警告,因为,作为警告告诉你,你是实例textfieldInt和textfield2Int,但你不使用你创建的整数textfieldInt,并textfield2Int要为计算let convert,但您添加字符串textField1.text!和textField2.text!在一起...

我想,你希望你的功能是这样的:

@IBAction func calculate(_ sender: AnyObject) {
    let textfieldInt: Int? = Int(textField1.text!)
    let textfield2Int: Int? = Int(textField2.text!)
    let convert = textfieldInt + textfield2Int
    let convertText = String(convert)
    output.text = convertText
}