SwiftUI -半模态？

Question

我正在尝试重新创建一个模式，就像iOS13 in SwiftUI中的Safari一样：

看上去是这样的：

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有人知道这在SwiftUI中是否可行吗？我想显示一个小的半模式，与选项拖到全屏，就像共享页。

任何建议都非常感谢！

Answer 1

iOS 16+

看起来，iOS 16最终支持半张表。

为了管理纸张的大小，我们可以使用PresentationDetent，特别是presentationDetents(_:selection:)

下面是来自文档的一个例子

struct ContentView: View {
    @State private var showSettings = false
    @State private var settingsDetent = PresentationDetent.medium

    var body: some View {
        Button("View Settings") {
            showSettings = true
        }
        .sheet(isPresented: $showSettings) {
            SettingsView()
                .presentationDetents:(
                    [.medium, .large],
                    selection: $settingsDetent
                 )
        }
    }
}

请注意，如果您提供了更多的止回器，人们可以拖动工作表来调整它的大小。

以下是PresentationDetent的可能值

• large
• medium
• fraction(CGFloat)
• height(CGFloat)
• custom<D>(D.Type)

Answer 2

在SWIFT5.5 iOS 15+和Mac催化剂15+中有一个

有一种新的adaptiveSheetPresentationController解决方案

4.

@available(iOS 15.0, *)
struct CustomSheetParentView: View {
    @State private var isPresented = false
    
    var body: some View {
        VStack{
            Button("present sheet", action: {
                isPresented.toggle()
            }).adaptiveSheet(isPresented: $isPresented, detents: [.medium()], smallestUndimmedDetentIdentifier: .large){
                Rectangle()
                    .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .center)
                    .foregroundColor(.clear)
                    .border(Color.blue, width: 3)
                    .overlay(Text("Hello, World!").frame(maxWidth: .infinity, maxHeight: .infinity)
                                .onTapGesture {
                        isPresented.toggle()
                    }
                    )
            }
            
        }
    }
}
@available(iOS 15.0, *)
struct AdaptiveSheet<T: View>: ViewModifier {
    let sheetContent: T
    @Binding var isPresented: Bool
    let detents : [UISheetPresentationController.Detent]
    let smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier?
    let prefersScrollingExpandsWhenScrolledToEdge: Bool
    let prefersEdgeAttachedInCompactHeight: Bool
    
    init(isPresented: Binding<Bool>, detents : [UISheetPresentationController.Detent] = [.medium(), .large()], smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier? = .medium, prefersScrollingExpandsWhenScrolledToEdge: Bool = false, prefersEdgeAttachedInCompactHeight: Bool = true, @ViewBuilder content: @escaping () -> T) {
        self.sheetContent = content()
        self.detents = detents
        self.smallestUndimmedDetentIdentifier = smallestUndimmedDetentIdentifier
        self.prefersEdgeAttachedInCompactHeight = prefersEdgeAttachedInCompactHeight
        self.prefersScrollingExpandsWhenScrolledToEdge = prefersScrollingExpandsWhenScrolledToEdge
        self._isPresented = isPresented
    }
    func body(content: Content) -> some View {
        ZStack{
            content
            CustomSheet_UI(isPresented: $isPresented, detents: detents, smallestUndimmedDetentIdentifier: smallestUndimmedDetentIdentifier, prefersScrollingExpandsWhenScrolledToEdge: prefersScrollingExpandsWhenScrolledToEdge, prefersEdgeAttachedInCompactHeight: prefersEdgeAttachedInCompactHeight, content: {sheetContent}).frame(width: 0, height: 0)
        }
    }
}
@available(iOS 15.0, *)
extension View {
    func adaptiveSheet<T: View>(isPresented: Binding<Bool>, detents : [UISheetPresentationController.Detent] = [.medium(), .large()], smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier? = .medium, prefersScrollingExpandsWhenScrolledToEdge: Bool = false, prefersEdgeAttachedInCompactHeight: Bool = true, @ViewBuilder content: @escaping () -> T)-> some View {
        modifier(AdaptiveSheet(isPresented: isPresented, detents : detents, smallestUndimmedDetentIdentifier: smallestUndimmedDetentIdentifier, prefersScrollingExpandsWhenScrolledToEdge: prefersScrollingExpandsWhenScrolledToEdge, prefersEdgeAttachedInCompactHeight: prefersEdgeAttachedInCompactHeight, content: content))
    }
}

@available(iOS 15.0, *)
struct CustomSheet_UI<Content: View>: UIViewControllerRepresentable {
    
    let content: Content
    @Binding var isPresented: Bool
    let detents : [UISheetPresentationController.Detent]
    let smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier?
    let prefersScrollingExpandsWhenScrolledToEdge: Bool
    let prefersEdgeAttachedInCompactHeight: Bool
    
    init(isPresented: Binding<Bool>, detents : [UISheetPresentationController.Detent] = [.medium(), .large()], smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier? = .medium, prefersScrollingExpandsWhenScrolledToEdge: Bool = false, prefersEdgeAttachedInCompactHeight: Bool = true, @ViewBuilder content: @escaping () -> Content) {
        self.content = content()
        self.detents = detents
        self.smallestUndimmedDetentIdentifier = smallestUndimmedDetentIdentifier
        self.prefersEdgeAttachedInCompactHeight = prefersEdgeAttachedInCompactHeight
        self.prefersScrollingExpandsWhenScrolledToEdge = prefersScrollingExpandsWhenScrolledToEdge
        self._isPresented = isPresented
    }
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    func makeUIViewController(context: Context) -> CustomSheetViewController<Content> {
        let vc = CustomSheetViewController(coordinator: context.coordinator, detents : detents, smallestUndimmedDetentIdentifier: smallestUndimmedDetentIdentifier, prefersScrollingExpandsWhenScrolledToEdge:  prefersScrollingExpandsWhenScrolledToEdge, prefersEdgeAttachedInCompactHeight: prefersEdgeAttachedInCompactHeight, content: {content})
        return vc
    }
    
    func updateUIViewController(_ uiViewController: CustomSheetViewController<Content>, context: Context) {
        if isPresented{
            uiViewController.presentModalView()
        }else{
            uiViewController.dismissModalView()
        }
    }
    class Coordinator: NSObject, UIAdaptivePresentationControllerDelegate {
        var parent: CustomSheet_UI
        init(_ parent: CustomSheet_UI) {
            self.parent = parent
        }
        //Adjust the variable when the user dismisses with a swipe
        func presentationControllerDidDismiss(_ presentationController: UIPresentationController) {
            if parent.isPresented{
                parent.isPresented = false
            }
            
        }
        
    }
}

@available(iOS 15.0, *)
class CustomSheetViewController<Content: View>: UIViewController {
    let content: Content
    let coordinator: CustomSheet_UI<Content>.Coordinator
    let detents : [UISheetPresentationController.Detent]
    let smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier?
    let prefersScrollingExpandsWhenScrolledToEdge: Bool
    let prefersEdgeAttachedInCompactHeight: Bool
    private var isLandscape: Bool = UIDevice.current.orientation.isLandscape
    init(coordinator: CustomSheet_UI<Content>.Coordinator, detents : [UISheetPresentationController.Detent] = [.medium(), .large()], smallestUndimmedDetentIdentifier: UISheetPresentationController.Detent.Identifier? = .medium, prefersScrollingExpandsWhenScrolledToEdge: Bool = false, prefersEdgeAttachedInCompactHeight: Bool = true, @ViewBuilder content: @escaping () -> Content) {
        self.content = content()
        self.coordinator = coordinator
        self.detents = detents
        self.smallestUndimmedDetentIdentifier = smallestUndimmedDetentIdentifier
        self.prefersEdgeAttachedInCompactHeight = prefersEdgeAttachedInCompactHeight
        self.prefersScrollingExpandsWhenScrolledToEdge = prefersScrollingExpandsWhenScrolledToEdge
        super.init(nibName: nil, bundle: .main)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    func dismissModalView(){
        dismiss(animated: true, completion: nil)
    }
    func presentModalView(){
        
        let hostingController = UIHostingController(rootView: content)
        
        hostingController.modalPresentationStyle = .popover
        hostingController.presentationController?.delegate = coordinator as UIAdaptivePresentationControllerDelegate
        hostingController.modalTransitionStyle = .coverVertical
        if let hostPopover = hostingController.popoverPresentationController {
            hostPopover.sourceView = super.view
            let sheet = hostPopover.adaptiveSheetPresentationController
            //As of 13 Beta 4 if .medium() is the only detent in landscape error occurs
            sheet.detents = (isLandscape ? [.large()] : detents)
            sheet.largestUndimmedDetentIdentifier =
            smallestUndimmedDetentIdentifier
            sheet.prefersScrollingExpandsWhenScrolledToEdge =
            prefersScrollingExpandsWhenScrolledToEdge
            sheet.prefersEdgeAttachedInCompactHeight =
            prefersEdgeAttachedInCompactHeight
            sheet.widthFollowsPreferredContentSizeWhenEdgeAttached = true
            
        }
        if presentedViewController == nil{
            present(hostingController, animated: true, completion: nil)
        }
    }
    /// To compensate for orientation as of 13 Beta 4 only [.large()] works for landscape
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)
        if UIDevice.current.orientation.isLandscape {
            isLandscape = true
            self.presentedViewController?.popoverPresentationController?.adaptiveSheetPresentationController.detents = [.large()]
        } else {
            isLandscape = false
            self.presentedViewController?.popoverPresentationController?.adaptiveSheetPresentationController.detents = detents
        }
    }
}

@available(iOS 15.0, *)
struct CustomSheetView_Previews: PreviewProvider {
    static var previews: some View {
        CustomSheetParentView()
    }
}

iOS 16 Beta

在iOS 16中，Beta苹果为半模态提供了纯SwiftUI解决方案。

    .sheet(isPresented: $showSettings) {
        SettingsView()
            .presentationDetents:(
                [.medium, .large],
                selection: $settingsDetent
             )
    }

还可以添加自定义支架并指定百分比。

static func custom<D>(D.Type) -> PresentationDetent
//A custom detent with a calculated height.
static func fraction(CGFloat) -> PresentationDetent
//A custom detent with the specified fractional height.
static func height(CGFloat) -> PresentationDetent
//A custom detent with the specified height.

示例：

extension PresentationDetent {
    static let bar = Self.fraction(0.2)
}

.sheet(isPresented: $showSettings) {
    SettingsView()
        .presentationDetents:([.bar])
}

Answer 3

我已经写了一个Swift软件包，其中包括一个自定义修饰符，允许您使用半模态表。

下面是链接：https://github.com/AndreaMiotto/PartialSheet

请随意使用它或作出贡献

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