ios - 有没有办法在 Swift 中满足某个条件时结束递归方法？

Question

我有一个函数，它返回一个值及其大小，可以根据计算标签宽度设置。满足某些条件后，我想停止递归函数的进一步过程，如 break。

func getLength(value: Int, font: UIFont, viewFrame: CGRect) -> (width:CGFloat, text:String) {
    let width: CGFloat!
     var val = value

    let size = String(format:"%d",value).size(attributes: [NSFontAttributeName: font])
    if size.width+10 > viewFrame.size.width {
        width = viewFrame.size.width-10
        val = val/10
        _ = getLength(value: val, font: font, viewFrame: viewFrame)
        return (0.0 , "")

    } else {
        width = size.width+10
        return (width,String(format:"%d+",val))
    }
}

Answer 1

当使用递归函数时，你应该在两种情况下都返回值

 func getLength(value: Int, font: UIFont, viewFrame: CGRect) -> (width:CGFloat, text:String) {
        let width: CGFloat!
         var val = value

        let size = String(format:"%d",value).size(attributes: [NSFontAttributeName: font])
        if size.width+10 > viewFrame.size.width {
            width = viewFrame.size.width-10
            val = val/10
            return getLength(value: val, font: font, viewFrame: viewFrame)

        } else {
            width = size.width+10
            return (width,String(format:"%d+",val))
        }
    }