在 SwiftUI macOS 应用程序中根据 NavigationView 更改窗口大小

Question

我正在将 SwiftUI 用于主窗口包含 NavigationView 的 Mac 应用程序。此 NavigationView 包含一个侧边栏列表。选择侧栏中的项目时，它会更改详细视图中显示的视图。详细视图中显示的视图大小不同，这应该会导致窗口大小在显示时发生变化。但是，当详细视图更改大小时，窗口不会更改大小以适应新的详细视图。

如何根据 NavigationView 的大小更改窗口大小？

我的应用程序示例代码如下：

import SwiftUI

struct View200: View {
    var body: some View {
        Text("200").font(.title)
            .frame(width: 200, height: 400)
            .background(Color(.systemRed))
    }
}

struct View500: View {
    var body: some View {
        Text("500").font(.title)
            .frame(width: 500, height: 300)
            .background(Color(.systemBlue))
    }
}

struct ViewOther: View {
    let item: Int
    var body: some View {
        Text("\(item)").font(.title)
            .frame(width: 300, height: 200)
            .background(Color(.systemGreen))
    }
}

struct DetailView: View {

    let item: Int

    var body: some View {
        switch item {
        case 2:
            return AnyView(View200())
        case 5:
            return AnyView(View500())
        default:
            return AnyView(ViewOther(item: item))
        }
    }
}

struct ContentView: View {
    var body: some View {
        NavigationView {
             List {
                 ForEach(1...10, id: \.self) { index in
                     NavigationLink(destination: DetailView(item: index)) {
                         Text("Link \(index)")
                     }
                 }
             }
             .listStyle(SidebarListStyle())
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

这是当详细视图更改大小时示例应用程序的样子：

Answer 1

这是可行的可能方法的演示。我是在一种不同的视图上完成的，因为您需要重新设计您的解决方案才能采用它。

演示

1）需要窗口动画调整大小的视图

struct ResizingView: View {
    public static let needsNewSize = Notification.Name("needsNewSize")

    @State var resizing = false
    var body: some View {
        VStack {
            Button(action: {
                self.resizing.toggle()
                NotificationCenter.default.post(name: Self.needsNewSize, object: 
                    CGSize(width: self.resizing ? 800 : 400, height: self.resizing ? 350 : 200))
            }, label: { Text("Resize") } )
        }
        .frame(minWidth: 400, maxWidth: .infinity, minHeight: 200, maxHeight: .infinity)
    }
}

2) 窗口的所有者（在本例中AppDelegate）

import Cocoa
import SwiftUI
import Combine

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    var window: NSWindow!
    var subscribers = Set<AnyCancellable>()

    func applicationDidFinishLaunching(_ aNotification: Notification) {

        let contentView = ResizingView()

        window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 480, height: 300), // just default
            styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
            backing: .buffered, defer: false)
        window.center()
        window.setFrameAutosaveName("Main Window")
        window.contentView = NSHostingView(rootView: contentView)
        window.makeKeyAndOrderFront(nil)

        NotificationCenter.default.publisher(for: ResizingView.needsNewSize)
            .sink(receiveCompletion: {_ in}) { [unowned self] notificaiton in
                if let size = notificaiton.object as? CGSize {
                    var frame = self.window.frame
                    let old = self.window.contentRect(forFrameRect: frame).size

                    let dX = size.width - old.width
                    let dY = size.height - old.height

                    frame.origin.y -= dY // origin in flipped coordinates
                    frame.size.width += dX
                    frame.size.height += dY
                    self.window.setFrame(frame, display: true, animate: true)
                }
            }
            .store(in: &subscribers)
    }
    ...