SwiftUI Notes 03

IntrospectWindowView.swift

import SwiftUI
import AppKit

extension View {
    public func inject<SomeView>(_ view: SomeView) -> some View where SomeView: View {
        overlay(view.frame(width: 0, height: 0))
    }
    
    func getWindow(window: @escaping (_ window: NSWindow?) -> Void) -> some View {
        inject(IntrospectWindowViewRepresentable(getWindow: window))
    }
}

struct IntrospectWindowViewRepresentable: NSViewRepresentable {
    let getWindow: (_ window: NSWindow?) -> Void
    
    init(getWindow: @escaping (_: NSWindow?) -> Void) {
        self.getWindow = getWindow
    }
    
    func makeNSView(context: Context) -> some NSView {
        let view = IntrospectWindowView(getWindow: self.getWindow)
        return view
    }
    
    func updateNSView(_ nsView: NSViewType, context: Context) {
//        self.getWindow(window: )
    }
}

class IntrospectWindowView: NSView {
    let getWindow: (_ window: NSWindow?) -> Void
    
    init(getWindow: @escaping (_: NSWindow?) -> Void) {
        self.getWindow = getWindow
        super.init(frame: .zero)
    }
    
    @available(*, unavailable)
    required init?(coder _: NSCoder) {
        fatalError("Create this view programmatically.")
    }
    
    override func viewDidMoveToWindow() {
        super.viewDidMoveToWindow()
        
        DispatchQueue.main.async {
            self.getWindow(self.window)
        }
    }
}

MainWindowController.swift

// Sample Code for Blog Post: How to access window from SwiftUI view?(Chinese) -> https://justinyan.me/post/5656

final class MainWindowController: NSWindowController {
    private var mainViewModel: MainViewModel? = nil
    
    convenience init() {
        let window = NSWindow.centeredWindow(size: .zero)
        let mainViewModel = MainViewModel()
        let mainView: MainView = MainView(viewModel: mainViewModel)
        window.contentViewController = NSHostingController(rootView: mainView)
        window.centerNatural()
        window.toolbarStyle = .unifiedCompact
        window.styleMask = [.closable, .miniaturizable, .unifiedTitleAndToolbar, .titled, .fullSizeContentView]
        window.titlebarAppearsTransparent = true
        
        self.init(window: window)
        self.mainViewModel = mainViewModel
        
        NSApp.activate(ignoringOtherApps: false)
        window.makeKeyAndOrderFront(nil)
    }
}

WindowReader.swift

// Sample Code for Blog Post: How to access window from SwiftUI view?(Chinese) -> https://justinyan.me/post/5656
// WindowReader source code From project -> https://github.com/aheze/Popovers

import Foundation
import AppKit
import SwiftUI

public struct WindowReader<Content: View>: View {
    /// Your SwiftUI view.
    public let view: (NSWindow?) -> Content

    /// The read window.
    @StateObject var windowViewModel = WindowViewModel()

    /// Reads the `NSWindow` that hosts some SwiftUI content.
    public init(@ViewBuilder view: @escaping (NSWindow?) -> Content) {
        self.view = view
    }

    public var body: some View {
        view(windowViewModel.window)
//            .id(windowViewModel.window)
            .background(
                WindowViewRepresentable(windowViewModel: windowViewModel)
            )

    }

    /// A wrapper view to read the parent window.
    private struct WindowViewRepresentable: NSViewRepresentable {
        @ObservedObject var windowViewModel: WindowViewModel

        func makeNSView(context _: Context) -> WindowView {
            return WindowView(windowViewModel: self.windowViewModel)
        }

        func updateNSView(_: WindowView, context _: Context) {}
    }

    private class WindowView: NSView {
        var windowViewModel: WindowViewModel

        init(windowViewModel: WindowViewModel) {
            self.windowViewModel = windowViewModel
            super.init(frame: .zero)
        }

        @available(*, unavailable)
        required init?(coder _: NSCoder) {
            fatalError("Should not init with coder")
        }

        override func viewDidMoveToWindow() {
            super.viewDidMoveToWindow()

            DispatchQueue.main.async {
                /// Set the window.
                self.windowViewModel.window = self.window
            }
        }
    }
}

class WindowViewModel: ObservableObject {
    @Published var window: NSWindow?
}