Add preliminary support for Qt for visionOS

Qt already runs on Vision Pro as "Designed for iPad", using Qt
for iOS. This change enables building Qt for visionOS directly,
which opens the door to visionOS specific APIs and use-cases
such as volumes and immersive spaces.

The platform removes some APIs we depend on, notably UIScreen,
so some code paths have been disabled or mocked to get something
up and running.

As our current window management approach on UIKit platforms
depends on UIWindow and UIScreen there is currently no way to
bring up QWindows. This will improve once we refactor our
window management to use window scenes.

To configure for visionOS, pass -platform macx-visionos-clang,
and optionally add -sdk xrsimulator to build for the simulator.

Change-Id: I4eda55fc3fd06e12d30a188928487cf68940ee07
Reviewed-by:  Alexey Edelev <alexey.edelev@qt.io>

1 files changed, 11 insertions, 3 deletions

diff --git a/src/plugins/platforms/ios/qiosviewcontroller.mm b/src/plugins/platforms/ios/qiosviewcontroller.mm
index 01a8a0d9b2..fa3fef26b6 100644
--- a/src/plugins/platforms/ios/qiosviewcontroller.mm
+++ b/src/plugins/platforms/ios/qiosviewcontroller.mm
@@ -88,6 +88,7 @@
 
 - (void)didAddSubview:(UIView *)subview
 {
+#if !defined(Q_OS_VISIONOS)
     Q_UNUSED(subview);
 
     QT_PREPEND_NAMESPACE(QIOSScreen) *screen = self.qtViewController.platformScreen;
@@ -103,10 +104,12 @@
         uiWindow.screen = screen->uiScreen();
         uiWindow.hidden = NO;
     }
+#endif
 }
 
 - (void)willRemoveSubview:(UIView *)subview
 {
+#if !defined(Q_OS_VISIONOS)
     Q_UNUSED(subview);
 
     UIWindow *uiWindow = self.window;
@@ -124,6 +127,7 @@
             uiWindow.screen = [UIScreen mainScreen];
         });
     }
+#endif
 }
 
 - (void)layoutSubviews
@@ -285,7 +289,7 @@
 
     Q_ASSERT(!qt_apple_isApplicationExtension());
 
-#ifndef Q_OS_TVOS
+#if !defined(Q_OS_TVOS) && !defined(Q_OS_VISIONOS)
     NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
     [center addObserver:self selector:@selector(willChangeStatusBarFrame:)
             name:UIApplicationWillChangeStatusBarFrameNotification
@@ -307,7 +311,7 @@
 
 - (BOOL)shouldAutorotate
 {
-#ifndef Q_OS_TVOS
+#if !defined(Q_OS_TVOS) && !defined(Q_OS_VISIONOS)
     return self.platformScreen && self.platformScreen->uiScreen() == [UIScreen mainScreen] && !self.lockedOrientation;
 #else
     return NO;
@@ -339,6 +343,7 @@
     [super didRotateFromInterfaceOrientation:orientation];
 }
 
+#if !defined(Q_OS_VISIONOS)
 - (void)willChangeStatusBarFrame:(NSNotification*)notification
 {
     Q_UNUSED(notification);
@@ -382,6 +387,7 @@
 
     [self.view setNeedsLayout];
 }
+#endif
 
 - (void)viewWillLayoutSubviews
 {
@@ -402,10 +408,12 @@
     if (!self.platformScreen || !self.platformScreen->screen())
         return;
 
+#if !defined(Q_OS_VISIONOS)
     // For now we only care about the main screen, as both the statusbar
     // visibility and orientation is only appropriate for the main screen.
     if (self.platformScreen->uiScreen() != [UIScreen mainScreen])
         return;
+#endif
 
     // Prevent recursion caused by updating the status bar appearance (position
     // or visibility), which in turn may cause a layout of our subviews, and
@@ -432,7 +440,7 @@
     // All decisions are based on the top level window
     focusWindow = qt_window_private(focusWindow)->topLevelWindow();
 
-#ifndef Q_OS_TVOS
+#if !defined(Q_OS_TVOS) && !defined(Q_OS_VISIONOS)
 
     // -------------- Status bar style and visbility ---------------