Qt access MainWindow from QOpenGLWidget

Question

I have a OpenGL widget inside the MainWindow.

I'd like to access MainWindow from its code.

I've tried it with the qApp->activeWindow() and findChild() combo but it does not work.

The WidgetOpenGLDraw constructor looks like: WidgetOpenGLDraw::WidgetOpenGLDraw(QWidget* parent):QOpenGLWidget(parent),gl(nullptr){}

EDIT1>

This also crashes: ((MainWindow*)qApp->activeWindow())->fname_here();.

Possible duplicate of [How to access to parent widget on qt?](http://stackoverflow.com/questions/352758/how-to-access-to-parent-widget-on-qt) — LogicStuff, Nov 13 '15 at 12:30
@LogicStuff I'm not doing anything with slots and I've already tried casting the parent argument from my constructor but it did not work. — Rok, Nov 13 '15 at 12:53
@LogicStuff If you meant something like this `(dynamic_cast((qApp->activeWindow())))->fname_here();` then it does not work. Did you mean I should try it with the parent constructor argument? — Rok, Nov 13 '15 at 13:13

score 1 · Accepted Answer · answered Nov 13 '15 at 14:10

QMainWindow isn't the parent of WidgetOpenGLDraw. QMainWindow has centralWidget() which is the parent of WidgetOpenGLDraw. So this might work.

MainWindow* mainWindow = qobject_cast<MainWindow*>(parentWidget()->parentWidget());
if (mainWindow) {
 // do stuff
}

score 0 · Answer 2 · answered Nov 13 '15 at 13:58

0

Looks like the QWidget* parent in the constructor is the QMainWindow. Store this as a member and you can access it from your WidgetOpenGLDraw class.

Doesn't sound nice but it should work.

answered Nov 13 '15 at 13:58

LiamT

112
5

Qt access MainWindow from QOpenGLWidget

2 Answers2