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
Fixes: QTBUG-80859
Change-Id: I769e58ead3c2efcf8c451c363108848feade9388
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
(cherry picked from commit 009abcd7b66738bece6cf354776dfb2ef401636b)
Reviewed-by: Liang Qi <liang.qi@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index db08a1d04f..b094172abb 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -8934,6 +8934,23 @@ 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;