SwiftUI 搜索栏

Question

我正在尝试构建一个可以通过工作表显示不同 pdf 的应用程序。到目前为止一切顺利，但我希望用户能够过滤通过搜索栏触发工作表修饰符的按钮。这对我不起作用。我尝试了来自 web 和 Stack Overflow 的不同解决方案，但没有一个对我有用。我想我必须从触发布尔表的按钮中过滤文本。但是怎么做？使用 List 或 ForEach 我不能每次都使用不同的 var/Bool 按钮。

下面是我的 Searchbar 类，只有一个 List 并对其进行过滤。

class SearchBar: NSObject, ObservableObject {
    
    
    let searchController: UISearchController = UISearchController(searchResultsController: nil)
    
    @Binding var text: String
    let hide : Bool
    let placeholder : String
    let cancelButton : Bool
    let autocapitalization : UITextAutocapitalizationType
    
    init(text: Binding<String>, hide: Bool, placeholder: String, cancelButton: Bool, autocapitalization: UITextAutocapitalizationType) {
        
        self._text = text
        self.hide = hide
        self.placeholder = placeholder
        self.cancelButton = cancelButton
        self.autocapitalization = autocapitalization
        
        super.init()
        
        
        self.searchController.obscuresBackgroundDuringPresentation = false
        self.searchController.searchResultsUpdater = self
        
        self.searchController.hidesNavigationBarDuringPresentation = hide
        self.searchController.automaticallyShowsCancelButton = cancelButton
        self.searchController.searchBar.placeholder = placeholder
        self.searchController.searchBar.autocapitalizationType = autocapitalization
        
    }
}

extension SearchBar: UISearchResultsUpdating {
   
    func updateSearchResults(for searchController: UISearchController) {
        
        // Publish search bar text changes.
        if let searchBarText = searchController.searchBar.text {
            self.text = searchBarText
        }
    }
}

struct SearchBarModifier: ViewModifier {
    
    let searchBar: SearchBar
    
    func body(content: Content) -> some View {
        content
            .overlay(
                ViewControllerResolver { viewController in
                    viewController.navigationItem.searchController = self.searchBar.searchController
                }
                    .frame(width: 0, height: 0)
            )
    }
}

extension View {
    
    func add(_ searchBar: SearchBar) -> some View {
        return self.modifier(SearchBarModifier(searchBar: searchBar))
    }
    
}

Answer 1

我的建议是将绑定替换为调用闭包并传递输入文本的操作。

将@Binding var text: String 行替换为

var action : ((String) -> Void)?

将updateSearchResults 替换为

func updateSearchResults(for searchController: UISearchController) {
    if let searchBarText = searchController.searchBar.text {
        DispatchQueue.main.async {  self.action?(searchBarText) }
    }
}

以及 ViewModifier 和视图扩展

struct SearchBarModifier: ViewModifier {
    
    let searchBar: SearchBar
    let action : ((String) -> Void)?
    
    func body(content: Content) -> some View {
        content
            .overlay(
                ViewControllerResolver { viewController in
                    searchBar.action = action
                    viewController.navigationItem.searchController = self.searchBar.searchController
                }
                .frame(width: 0, height: 0)
            )
    }
}

extension View {
   func add(_ searchBar: SearchBar, action : ((String) -> Void)?) -> some View {
       return self.modifier(SearchBarModifier(searchBar: searchBar, action: action))
   }
}

---

在视图中您可以添加搜索栏

.add(self.searchBar, action: { query in
    // do something with query
})

只要用户按下某个键，就会调用闭包。

如果您想在用户按下 Search/Go 键时调用一次闭包，您必须实现 searchBarSearchButtonClicked 并添加另一个操作。