UIViewController视图消失后隐藏inputAccessoryView

Question

我实现了这样的停靠inputAccessoryView：

lazy var inputView: UIView = {
    // custom creation
}()

override var inputAccessoryView: UIView? {
    return inputView
}

override var canBecomeFirstResponder: Bool {
    return true
}

它的效果非常好，问题是{I}隐藏了UIViewController之后隐藏inputView（它可见1秒钟，然后消失）。