swift - 如果语句不适用于三位数？

Question

这是一个简单的问题。

 if cell.count.text == "\(0)"
    {
        cell.pText.textColor = UIColor.grayColor()
        cell.nicebutton!.setImage(UIImage(named:"defaulltup"), forState: UIControlState.Normal)
        cell.nopebutton!.setImage(UIImage(named:"defaultdown"), forState: UIControlState.Normal)
        cell.count.textColor = UIColor.grayColor()
        cell.time.textColor = UIColor.grayColor()
    }
    if cell.count.text >= "\(1)"
    {
        cell.pText.textColor = UIColor.whiteColor()
        //cell.time.textColor = UIColor(red: 42.0/255, green: 204.0/255, blue: 113.0/255, alpha: 1)
        cell.count.textColor = UIColor(red: 42.0/255, green: 204.0/255, blue: 113.0/255, alpha: 1)
        cell.nicebutton!.setImage(UIImage(named:"upgreen"), forState: UIControlState.Normal)
        cell.nopebutton!.setImage(UIImage(named:"defaultdown"), forState: UIControlState.Normal)
        //cell.nopebutton!.setImage(UIImage(named:"downred"), forState: UIControlState.Normal)
        cell.count.textColor = UIColor(red: 42.0/255, green: 204.0/255, blue: 113.0/255, alpha: 1)
    }
    if cell.count.text < "\(0)"
    {
        cell.pText.textColor = UIColor(red: 231.0/255, green: 76.0/255, blue: 50.0/255, alpha: 1)
        //cell.time.textColor = UIColor(red: 231.0/255, green: 76.0/255, blue: 50.0/255, alpha: 1)
        cell.count.textColor = UIColor(red: 231.0/255, green: 76.0/255, blue: 50.0/255, alpha: 1)
        cell.nicebutton!.setImage(UIImage(named:"defaulltup"), forState: UIControlState.Normal)
        //cell.nicebutton!.setImage(UIImage(named:"upgreen"), forState: UIControlState.Normal)
        cell.nopebutton!.setImage(UIImage(named:"downred"), forState: UIControlState.Normal)

    }
    if cell.count.text >= "\(99)"
    {

        cell.pText.textColor = UIColor(red: 249.0/255, green: 191.0/255, blue: 59.0/255, alpha: 1)
        //cell.nopebutton!.setImage(UIImage(named:"downred"), forState: UIControlState.Normal)
        cell.nicebutton!.setImage(UIImage(named:"golden"), forState: UIControlState.Normal)
        cell.count.textColor = UIColor(red: 249.0/255, green: 191.0/255, blue: 59.0/255, alpha: 1)
    }

最后一个 if 语句根本不起作用，而其他语句却能正常工作。我真的很困惑为什么会这样。

Answer 1

首先，在您的代码中，您使用 < 比较字符串(不是 字符串中包含的数字)和 >运营商。这可能不是您想要做的。根据 Swift 文档:

For characters in strings, “greater than” means “appears later in the alphabet than”

字符串的比较结果与仅比较数字的结果不同，例如表达式 "2" > "10"是真的，当然2 > 10是假的。

如果你想比较字符串中包含的数字，你可以这样做:

if cell.count.text.toInt() == 0
// etc.

此外，如果您编写了 if，它会帮助您避免错误像这样的条件:

if condition1 {
    //...
}
else if condition2 {
    //...
}
else {
    //...
}

在您当前的代码中，如果其中一个条件不正确，则可以针对 cell.count.text 的相同值执行多个代码块。 .