将不明确的引用转换为 swift 3

Question

我正在尝试转换为 Swift 3 并收到以下错误：

'?' must be followed by a call, member lookup, or subscript

我的代码：

var superview = containerView.superview

if type(of: superview?) === UIWindow.self { //I GET AN ERROR HERE
    superview = containerView
}

建议？

Answer 1

测试类型最简单、最自然的方法是 is 关键字：

var superview = containerView.superview

if superview is UIWindow {
    superview = containerView
}