ios - 为什么我不能正确地将这张卡放在 UIScrollView 上？

Question

我已经指定了卡片的框架，为什么我不能将这张卡片添加到滚动视图中？

当我尝试将它添加到 UIScrollView 时，它只会变成一个带条。无法显示内容（标签）或工具栏（带有标题和详细信息以及图标按钮）。

滚动视图的代码

eventList = UIScrollView()
    eventList?.frame = CGRect(x: 0, y: (calender?.frame.height)! + (calenderMenu?.frame.height)!, width: ScreenWidth, height: ScreenHeight - (calenderMenu?.frame.height)! - (calender?.frame.height)!)
    eventList?.scrollsToTop = true
    eventList?.isScrollEnabled = true
    eventList?.bounces = true
    eventList?.isPagingEnabled = true
    eventList?.indicatorStyle = .default
    eventList?.contentSize = CGSize(width: ScreenWidth - 20, height: 400)
    eventList?.delegate = self
    self.view.addSubview(eventList!)

卡代码

signinCard = Card()
    signinCard?.frame = view.bounds

    signinCard?.toolbar = signinToolbar
    signinCard?.toolbarEdgeInsetsPreset = .square3
    signinCard?.toolbarEdgeInsets.bottom = 0
    signinCard?.toolbarEdgeInsets.right = 8

    signinCard?.contentView = contentView
    signinCard?.contentViewEdgeInsetsPreset = .wideRectangle3

    signinCard?.bottomBar = Bar()

    signinCard?.frame = CGRect(x: 10, y: 10, width: ScreenWidth - 20, height: (eventList?.frame.height)! / 2 - 5)
    eventList?.addSubview(signinCard!)