ios - 警告 : Value was defined but never used; consider replacing with a boolean test

Question

我有一个函数收到以下警告:

Value intVal was defined but never used; consider replacing with a boolean test.

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool 
{
    text = (timerTxtFld.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)
    if let intVal = Int(text) {
        timerDoneBtn.alpha = 1
        timerDoneBtn.enabled = true
    } else {
        timerDoneBtn.enabled = false
    }
    return true
}

谁能帮我弄清楚我需要做什么来消除错误？

Answer 1

只需删除 let 并直接对 Int 的结果进行比较。您无缘无故地创建了 intVal，它提示说这是一个未使用的变量。

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool 
{
    text = (timerTxtFld.text! as NSString).stringByReplacingCharactersInRange(range, withString: string)
    if Int(text) != nil
    {
        timerDoneBtn.alpha = 1
        timerDoneBtn.enabled = true
    }
    else
    {
        timerDoneBtn.enabled = false
    }
    return true
}