如何在Swift中模仿Safari的搜索栏UI /动画？

Question

我正在尝试在当前应用程序的iOS Safari中模仿以下搜索栏行为：

我主要希望导航栏在用户滚动内容时向上滚动至很小的版本，并在用户向上滚动时返回。

我尝试使用scrollViewDidScroll，但是似乎无法模仿它。我不确定是否将搜索栏正确添加到导航栏中。

let searchBar: UISearchBar = {
    let sb = UISearchBar()
    sb.autocapitalizationType = .none
    sb.autocorrectionType = .no
    sb.keyboardAppearance = UIKeyboardAppearance.default
    sb.placeholder = "Search"
    return sb
}()

fileprivate func setupNav() {
    //Basic Setup
    navigationController?.navigationBar.isTranslucent = true
    navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)

    //Search Bar
    searchBar.sizeToFit()
    navigationItem.titleView = searchBar
}

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    //Implement
}

Answer 1

let searchController                                  = UISearchController(searchResultsController: nil)
searchController.dimsBackgroundDuringPresentation     = false
searchController.searchBar.placeholder                = "Search"
searchController.searchResultsUpdater                 = self
navigationItem.searchController                       = searchController
definesPresentationContext                            = true 

将SearchController放在导航项中。这将添加可折叠的SearchBar。另外，您可以尝试将导航项Prompt放在顶部获得很小的标题。