ios - Swift 3 中的动态类型

Question

我已经将我的 swift 版本从 2.3 迁移到 3，它自动转换了一些代码，下面是我崩溃的情况我已经尝试了一些选项但徒劳无功，

swift 2.3:工作正常

public func huntSuperviewWithClassName(className: String) -> UIView?
{
    var foundView: UIView? = nil

    var currentVeiw:UIView? = self

    while currentVeiw?.superview != nil{
        if let classString = String.fromCString(class_getName(currentVeiw?.dynamicType)){

            if let classNameWithoutPackage = classString.componentsSeparatedByString(".").last{
                print(classNameWithoutPackage)
                if classNameWithoutPackage == className{
                    foundView = currentVeiw
                    break
                }
            }
        }
        currentVeiw = currentVeiw?.superview
    }

    return foundView
}

swift 3:不好

  if let classString = String(validatingUTF8: class_getName(type(of:currentVeiw) as! AnyClass)) {

也试过这条线:

  if let classString = String(describing: class_getName(type(of: currentVeiw) as! AnyClass)){

但是没用..

请指导我如何根据 swift 3 更正此行:

 if let classString = String.fromCString(class_getName(currentVeiw?.dynamicType)){

Answer 1

编译器告诉你不能使用 if let 因为它完全没有必要。您没有任何要解包的可选值。if let 专门用于解包可选值。

public func huntSuperviewWithClassName(className: String) -> UIView?
{
    var foundView: UIView? = nil

    var currentVeiw:UIView? = self

    while currentVeiw?.superview != nil{

            let classString = NSStringFromClass((currentVeiw?.classForCoder)!)

            if let classNameWithoutPackage = classString.components(separatedBy:".").last{
                print(classNameWithoutPackage)
                if classNameWithoutPackage == className{
                    foundView = currentVeiw
                    break
                }
            }
        }
        currentVeiw = currentVeiw?.superview
    }

    return foundView
}

工作正常!