From 4e4ffd3cc9c4b27550642c6233ed8a3177065bdb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20Jen=C3=9Fen?= <tim.jenssen@qt.io>
Date: Fri, 4 Apr 2025 17:47:44 +0200
Subject: [PATCH] QmlDesigner: fix windowHandle() is nullptr warning
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Change-Id: Ib5ec37ebce4899cc0af2be44a58928d43ce4c757
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>
---
 .../qmldesignerbase/utils/windowmanager.cpp   | 31 ++++++++++++++++---
 .../qmldesignerbase/utils/windowmanager.h     |  3 +-
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/plugins/qmldesignerbase/utils/windowmanager.cpp b/src/plugins/qmldesignerbase/utils/windowmanager.cpp
index a254da69ab0..5b7ed2131fc 100644
--- a/src/plugins/qmldesignerbase/utils/windowmanager.cpp
+++ b/src/plugins/qmldesignerbase/utils/windowmanager.cpp
@@ -19,11 +19,32 @@ WindowManager::WindowManager()
     connect(qGuiApp, &QGuiApplication::focusWindowChanged, this, &WindowManager::focusWindowChanged);
     connect(
         Core::ICore::instance(), &Core::ICore::coreAboutToClose, this, &WindowManager::aboutToQuit);
-    connect(
-        Core::ICore::instance()->mainWindow()->windowHandle(),
-        &QWindow::visibleChanged,
-        this,
-        &WindowManager::mainWindowVisibleChanged);
+
+    if (!connectMainWindowHandle())
+        Core::ICore::instance()->mainWindow()->installEventFilter(this);
+}
+
+bool WindowManager::connectMainWindowHandle()
+{
+    if (QWindow *windowHandle = Core::ICore::instance()->mainWindow()->windowHandle()) {
+        QMetaObject::Connection success = connect(
+            windowHandle,
+            &QWindow::visibleChanged,
+            this,
+            &WindowManager::mainWindowVisibleChanged,
+            Qt::UniqueConnection);
+        return success;
+    }
+    return false;
+}
+
+bool WindowManager::eventFilter(QObject *watched, QEvent *event)
+{
+    if (watched == Core::ICore::instance()->mainWindow() && event->type() == QEvent::WinIdChange) {
+        connectMainWindowHandle();
+        Core::ICore::instance()->mainWindow()->removeEventFilter(this);
+    }
+    return QObject::eventFilter(watched, event);
 }
 
 void WindowManager::registerDeclarativeType()
diff --git a/src/plugins/qmldesignerbase/utils/windowmanager.h b/src/plugins/qmldesignerbase/utils/windowmanager.h
index 1e74c721bc6..d329b53dc98 100644
--- a/src/plugins/qmldesignerbase/utils/windowmanager.h
+++ b/src/plugins/qmldesignerbase/utils/windowmanager.h
@@ -35,6 +35,7 @@ signals:
 
 private:
     WindowManager();
+    bool connectMainWindowHandle();
+    bool eventFilter(QObject *watched, QEvent *event) override;
 };
-
 } // namespace QmlDesigner