UITabBarViewController 的自定义 TabBar 布局

Question

请参考这个Answer。

我正在尝试做同样的事情，但是我想在标签栏应用程序中执行此操作，其中正在播放栏位于应用程序所有场景中的标签栏上方。

更新：

我想在屏幕底部（标签栏上方）和不同标签的内容视图下方（而不是在它们上方）有一个视图。此外，我希望能够在某个点移除此视图，使主视图占据整个屏幕。

我可以使用提到的Answer 以编程方式更改nowPlaying 视图的约束来做到这一点。

Answer 1

你将把你的视图/容器添加到你的应用window，你会做类似的事情

guard let window = (UIApplication.shared.delegate as? AppDelegate)?.window 
     else { return } // check if there's a window 

    let containerHeight: CGFloat = 50  // height for the view where you wish to add the music player 

   let containerFrame = CGRect(x:0, y: window.frame.maxY - (tabBar.frame.height + containerHeight), width: window.frame.width, height: containerHeight)
   // most important part here is the y axis in some sense, you will add the height of the tabBar and the container, then subtract it from window.frame.maxY  

   let container = UIView(frame: containerFrame)
   // now you have the container do whatever you want with it 
   window.addSubView(container) // finally add the container to window as a subview 

Answer 2

使用 UITabBarViewController 子类是可能的：

例如：

class DashBoardViewController: UITabBarController {

    let nowPlayingBar:UIView = {
        let view = UIView(frame: .zero)
        view.backgroundColor = .blue
        return view
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        initView()
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        nowPlayingBar.frame = tabBar.frame
    }

    override func viewDidAppear(_ animated: Bool) {
        var newSafeArea = UIEdgeInsets()

        // Adjust the safe area to accommodate
        //  the height of the bottom views.
        newSafeArea.bottom += nowPlayingBar.bounds.size.height

        // Adjust the safe area insets of the
        //  embedded child view controller.
        self.childViewControllers.forEach({$0.additionalSafeAreaInsets = newSafeArea})
    }

    private func initView() {
        nowPlayingBar.frame = tabBar.frame
        view.addSubview(nowPlayingBar)
    }
}