QWidget: React to platform surface being created or destroyed

The platform window may create or destroy its surface from other entry
points than the QWidget API, in which case QWidget needs to sync up
its own state to match. In particular WA_WState_Created and the winId
needs to be recomputed.

Fixes: QTBUG-69289
Fixes: QTBUG-77350
Change-Id: I769e58ead3c2efcf8c451c363108848feade9388
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 5a0ea58cf8..dcc694efe4 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -8624,6 +8624,23 @@ bool QWidget::event(QEvent *event)
         }
     }
     switch (event->type()) {
+    case QEvent::PlatformSurface: {
+        // Sync up QWidget's view of whether or not the widget has been created
+        switch (static_cast<QPlatformSurfaceEvent*>(event)->surfaceEventType()) {
+        case QPlatformSurfaceEvent::SurfaceCreated:
+            if (!testAttribute(Qt::WA_WState_Created))
+                create();
+            break;
+        case QPlatformSurfaceEvent::SurfaceAboutToBeDestroyed:
+            if (testAttribute(Qt::WA_WState_Created)) {
+                // Child windows have already been destroyed by QWindow,
+                // so we skip them here.
+                destroy(false, false);
+            }
+            break;
+        }
+        break;
+    }
     case QEvent::MouseMove:
         mouseMoveEvent((QMouseEvent*)event);
         break;