Question

I am trying to move my QSystemTrayIcon module to a separate thread. I am getting the below error while running the application. The Initialize() method addAction causing the error.

QWidget: Must construct a QApplication before a QPaintDevice

My sample code snippets:

Declared the global variable
QMenu myMenu;

Member Variable in the header file
QAction* openFile;

In the constructor
openFile = new QAction(parent);

Initialize() 
{
myMenu.addAction(openFile);
}

 void myApp::run()
 {
     Initialize()
 }

Answer 1

You must not use any GUI-related classes outside your main thread, i.e. the one QApplication was created in. Hence you cannot move your QSystemTrayIcon stuff in a separate thread. And no, there is no workaround.