How to disabled fullscreen button on MacCatalyst - swift

Question

Currently, I have this to stop resizing window:
#if targetEnvironment(macCatalyst)
windowScene.sizeRestrictions?.minimumSize = CGSize(width: 480, height: 900)
windowScene.sizeRestrictions?.maximumSize = CGSize(width: 480, height: 900)
#endif
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: contentView)
self.window = window
window.makeKeyAndVisible()
but the fullscreen button makes it full screen anyway.

Answer 1

Here is another approach that does not need Objective-C, selectors, or asynchronous calls. It also does not need target macros, iOS will simply skip if let NSApplication. Paste it into your view controller that appears first. Note that this disables the green full-screen button on all your windows. If you want to differentiate, use ideas from Asperi's Swift part.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
func bitSet(_ bits: [Int]) -> UInt {
return bits.reduce(0) { $0 | (1 << $1) }
}
func property(_ property: String, object: NSObject, set: [Int], clear: [Int]) {
if let value = object.value(forKey: property) as? UInt {
object.setValue((value & ~bitSet(clear)) | bitSet(set), forKey: property)
}
}
// disable full-screen button
if let NSApplication = NSClassFromString("NSApplication") as? NSObject.Type,
let sharedApplication = NSApplication.value(forKeyPath: "sharedApplication") as? NSObject,
let windows = sharedApplication.value(forKeyPath: "windows") as? [NSObject]
{
for window in windows {
let resizable = 3
property("styleMask", object: window, set: [], clear: [resizable])
let fullScreenPrimary = 7
let fullScreenAuxiliary = 8
let fullScreenNone = 9
property("collectionBehavior", object: window, set: [fullScreenNone], clear: [fullScreenPrimary, fullScreenAuxiliary])
}
}
}

Answer 2

It's a bit complicated but possible. Here is an approach (I dropped all target macros to simplify post).
Result:
Code:
// on next event after UIWindow has made key it is possible to find NSWindow in runtime
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
...
window.makeKeyAndVisible()
DispatchQueue.main.async { // < wait for NSWindow available
SilentBridge.disableCloseButton(for: self.nsWindow(from: window))
}
}
// added helper function to SceneDelegate to find NSWindow
func nsWindow(from window: UIWindow) -> NSObject? {
guard let nsWindows = NSClassFromString("NSApplication")?.value(forKeyPath: "sharedApplication.windows") as? [NSObject] else { return nil }
for nsWindow in nsWindows {
let uiWindows = nsWindow.value(forKeyPath: "uiWindows") as? [UIWindow] ?? []
if uiWindows.contains(window) {
return nsWindow
}
}
return nil
}
Objective-C part is preferred (it's just simpler to work with non-declared selectors). Add new Objective-C class via Xcode template and confirm creating bridge. Afterwards it is needed to add below class header file in generated *-Bridging-Header.h and all should work.
// SilentBridge.h
#import Foundation;
#interface SilentBridge : NSObject
+ (void)disableCloseButtonFor:(NSObject * _Nullable)window;
#end
// SilentBridge.m
#import "SilentBridge.h"
#import Foundation;
// Forward declarations to allow direct calls in below method
#interface NSObject(SilentBridge)
- (id)standardWindowButton:(NSInteger)value;
- (void)setEnabled:(BOOL)flag;
#end
#implementation SilentBridge
+ (void)disableCloseButtonFor:(NSObject *)window {
if ([window respondsToSelector:#selector(standardWindowButton:)]) {
id closeButton = [window standardWindowButton:2];
if ([closeButton respondsToSelector:#selector(setEnabled:)]) {
[closeButton setEnabled:NO];
}
}
}
#end