iPad 上具有自定义尺寸的 SwiftUI Sheet() 模式

如何使用 SwiftUI 控制 iPad 上模态表的首选演示大小？我很惊讶在谷歌上找到这个问题的答案是多么困难。

另外，了解模式是否通过向下拖动（取消）或实际执行自定义积极操作来关闭的最佳方法是什么？

以下是我在 iPad 上使用 SwiftUI 显示表单的解决方案：

struct MyView: View {
    @State var show = false

    var body: some View {
        Button("Open Sheet") { self.show = true }
            .formSheet(isPresented: $show) {
                Text("Form Sheet Content")
            }
    }
}

通过此 UIViewControllerRepresentable 启用

class FormSheetWrapper<Content: View>: UIViewController, UIPopoverPresentationControllerDelegate {

    var content: () -> Content
    var onDismiss: (() -> Void)?

    private var hostVC: UIHostingController<Content>?

    required init?(coder: NSCoder) { fatalError("") }

    init(content: @escaping () -> Content) {
        self.content = content
        super.init(nibName: nil, bundle: nil)
    }

    func show() {
        guard hostVC == nil else { return }
        let vc = UIHostingController(rootView: content())

        vc.view.sizeToFit()
        vc.preferredContentSize = vc.view.bounds.size

        vc.modalPresentationStyle = .formSheet
        vc.presentationController?.delegate = self
        hostVC = vc
        self.present(vc, animated: true, completion: nil)
    }

    func hide() {
        guard let vc = self.hostVC, !vc.isBeingDismissed else { return }
        dismiss(animated: true, completion: nil)
        hostVC = nil
    }

    func presentationControllerWillDismiss(_ presentationController: UIPresentationController) {
        hostVC = nil
        self.onDismiss?()
    }
}

struct FormSheet<Content: View> : UIViewControllerRepresentable {

    @Binding var show: Bool

    let content: () -> Content

    func makeUIViewController(context: UIViewControllerRepresentableContext<FormSheet<Content>>) -> FormSheetWrapper<Content> {

        let vc = FormSheetWrapper(content: content)
        vc.onDismiss = { self.show = false }
        return vc
    }

    func updateUIViewController(_ uiViewController: FormSheetWrapper<Content>,
                                context: UIViewControllerRepresentableContext<FormSheet<Content>>) {
        if show {
            uiViewController.show()
        }
        else {
            uiViewController.hide()
        }
    }
}

extension View {
    public func formSheet<Content: View>(isPresented: Binding<Bool>,
                                          @ViewBuilder content: @escaping () -> Content) -> some View {
        self.background(FormSheet(show: isPresented,
                                  content: content))
    }
}

您应该能够修改其中的代码func show()根据 UIKit 规范，以便按照您喜欢的方式调整大小（如果需要，您甚至可以从 SwiftUI 端注入参数）。这就是我如何获取在 iPad 上使用的表单.sheet对于我的用例来说太大了