Can I disable the window resizing feature on my Mac Catalyst iOS app

Question

I'm migrating my iOS app to support MacCatalyst but I'd like to prevent the window from being resized by the user.

Do you have any tips for that?

Answer 1

Since Xcode11 Beta 5, the UIWindowScene class started supporting the property sizeRestrictions .

If you set sizeRestrictions.maximumSize and sizeRestrictions.minimumSize to the same value, the window will not be resizable. To do so, just call this in your application:didFinishLaunchingWithOptions method (if you're using UIKit ):

    UIApplication.shared.connectedScenes.compactMap { $0 as? UIWindowScene }.forEach { windowScene in
        windowScene.sizeRestrictions?.minimumSize = CGSize(width: 480, height: 640)
        windowScene.sizeRestrictions?.maximumSize = CGSize(width: 480, height: 640)
    }

If you're using SwiftUI instead of UIKit, you should actually add it to scene(_:willConnectTo:options:) in your scene delegate.

Note: You need to run this in OSX 10.15 Beta 5 or later, otherwise it will crash

Answer 2

In a SwiftUI App lifecycle this worked for me:

import SwiftUI

@main
struct MyApp: App {

  @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
  
  var userSettings = UserSettings()
  
  var body: some Scene {
    WindowGroup {
      ContentView()
        .environmentObject(userSettings)
        .environmentObject(KeyboardManager())
        .onOpenURL(perform: { url in
          let verificationCode = url.lastPathComponent
          log.info("🔢 Verification Code: \(verificationCode)")
          userSettings.verificationCode = verificationCode
        })
      .onReceive(NotificationCenter.default.publisher(for: UIScene.willConnectNotification)) { _ in
        #if targetEnvironment(macCatalyst)
        // prevent window in macOS from being resized down
          UIApplication.shared.connectedScenes.compactMap { $0 as? UIWindowScene }.forEach { windowScene in
            windowScene.sizeRestrictions?.minimumSize = CGSize(width: 800, height: 1000)
          }
        #endif
      }
    }
  }
}

Answer 3

In the file, SceneDelegate.swift, add this:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
    UIApplication.shared.connectedScenes.compactMap { $0 as? UIWindowScene }.forEach { windowScene in
        windowScene.sizeRestrictions?.minimumSize = CGSize(width: 1268, height: 880)
        windowScene.sizeRestrictions?.maximumSize = windowScene.sizeRestrictions!.minimumSize
    }
    
    guard let _ = (scene as? UIWindowScene) else { return }
}

Answer 4

for Objective-C try

for (UIScene* scene in UIApplication.sharedApplication.connectedScenes) {
    if ([scene isKindOfClass:[UIWindowScene class]]) {
        UIWindowScene* windowScene = (UIWindowScene*) scene;
        windowScene.sizeRestrictions.minimumSize = CGSizeMake(480, 640);
    }
}