iOS: Support message box at startup without relying on screen's window

Task-number: QTBUG-121781
Change-Id: Iafc911dad6c668799383f423e38ab389c29688b4
Reviewed-by: Doris Verria <doris.verria@qt.io>

2 files changed, 17 insertions, 20 deletions

diff --git a/src/plugins/platforms/ios/qiosglobal.mm b/src/plugins/platforms/ios/qiosglobal.mm
index 169c292a00..8d0df38dbe 100644
--- a/src/plugins/platforms/ios/qiosglobal.mm
+++ b/src/plugins/platforms/ios/qiosglobal.mm
@@ -88,10 +88,15 @@ int infoPlistValue(NSString* key, int defaultValue)
 UIWindow *presentationWindow(QWindow *window)
 {
     UIWindow *uiWindow = window ? reinterpret_cast<UIView *>(window->winId()).window : nullptr;
-#if !defined(Q_OS_VISIONOS)
-    if (!uiWindow)
-        uiWindow = qt_apple_sharedApplication().keyWindow;
-#endif
+    if (!uiWindow) {
+        auto *scenes = [qt_apple_sharedApplication().connectedScenes allObjects];
+        if (scenes.count > 0) {
+            auto *windowScene = static_cast<UIWindowScene*>(scenes[0]);
+            uiWindow = windowScene.keyWindow;
+            if (!uiWindow && windowScene.windows.count)
+                uiWindow = windowScene.windows[0];
+        }
+    }
     return uiWindow;
 }
 
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.mm b/src/plugins/platforms/ios/qiosmessagedialog.mm
index 979829377a..7fbd5d8729 100644
--- a/src/plugins/platforms/ios/qiosmessagedialog.mm
+++ b/src/plugins/platforms/ios/qiosmessagedialog.mm
@@ -117,25 +117,17 @@ bool QIOSMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality win
     }
 
     UIWindow *window = presentationWindow(parent);
-    if (!window) {
-        qCDebug(lcQpaWindow, "Attempting to exec a dialog without any window/widget visible.");
-
-        auto *primaryScreen = static_cast<QIOSScreen*>(QGuiApplication::primaryScreen()->handle());
-        Q_ASSERT(primaryScreen);
-
-        window = primaryScreen->uiWindow();
-        if (window.hidden) {
-            // With a window hidden, an attempt to present view controller
-            // below fails with a warning, that a view "is not a part of
-            // any view hierarchy". The UIWindow is initially hidden,
-            // as unhiding it is what hides the splash screen.
-            window.hidden = NO;
-        }
-    }
-
     if (!window)
         return false;
 
+    if (window.hidden) {
+         // With a window hidden, an attempt to present view controller
+         // below fails with a warning, that a view "is not a part of
+         // any view hierarchy". The UIWindow is initially hidden,
+         // as unhiding it is what hides the splash screen.
+         window.hidden = NO;
+    }
+
     [window.rootViewController presentViewController:m_alertController animated:YES completion:nil];
     return true;
 }