fixes #11533: TypeError in: FreeCADGui.getMainWindow().windowStateChanged

src/Gui/MDIView.cpp

@@ -226,12 +226,14 @@ void MDIView::closeEvent(QCloseEvent *e)
         // because otherwise other parts don't work as they should.
         QMainWindow::closeEvent(e);
     }
-    else
+    else {
         e->ignore();
+    }
 }
 
-void MDIView::windowStateChanged( MDIView* )
+void MDIView::windowStateChanged(QWidget* view)
 {
+    Q_UNUSED(view)
 }
 
 void MDIView::print(QPrinter* printer)

src/Gui/MDIView.h

@@ -166,7 +166,7 @@ protected Q_SLOTS:
      * whenever the window state of the active view changes.
      * The default implementation does nothing.
      */
-    virtual void windowStateChanged(Gui::MDIView*);
+    virtual void windowStateChanged(QWidget*);
 
 protected:
     void closeEvent(QCloseEvent *e) override;

src/Gui/MainWindow.h

@@ -347,7 +347,7 @@ private Q_SLOTS:
 
 Q_SIGNALS:
     void timeEvent();
-    void windowStateChanged(Gui::MDIView*);
+    void windowStateChanged(QWidget*);
     void workbenchActivated(const QString&);
     void mainWindowClosed();
 

src/Gui/PythonWrapper.cpp

@@ -189,8 +189,7 @@ PythonToCppFunc toCppPointerCheckFuncQuantity(PyObject* obj)
 {
     if (PyObject_TypeCheck(obj, &(Base::QuantityPy::Type)))
         return toCppPointerConvFuncQuantity;
-    else
-        return nullptr;
+    return nullptr;
 }
 
 void BaseQuantity_PythonToCpp_QVariant(PyObject* pyIn, void* cppOut)

src/Gui/View3DInventor.cpp

@@ -675,7 +675,7 @@ void View3DInventor::dump(const char* filename, bool onlyVisible)
     }
 }
 
-void View3DInventor::windowStateChanged(MDIView* view)
+void View3DInventor::windowStateChanged(QWidget* view)
 {
     bool canStartTimer = false;
     if (this != view) {

src/Gui/View3DInventor.h

@@ -125,7 +125,7 @@ private:
     void applySettings();
 
 protected:
-    void windowStateChanged(MDIView* ) override;
+    void windowStateChanged(QWidget* view) override;
     void dropEvent        (QDropEvent      * e) override;
     void dragEnterEvent   (QDragEnterEvent * e) override;
     void keyPressEvent    (QKeyEvent       * e) override;