Question

I am attempting to add a “Full Screen” option to my Qt (using PyQt) application. If the user hits F11, the goal is to maximize the window.

I am having problems removing the window title bar though. Normally, I’d do something like self.setWindowFlags(QtCore.Qt.CustomizeWindowHint) in __init__ and the title bar would not display (expected behavior). However, if I launch the Qt application, and then wait for the user to press F11 like so:

def keyPressEvent(self, event):
    if event.key() == QtCore.Qt.Key_F11:
        self.__doFullScreenCheck()

def __doFullScreenCheck(self):
    if self.maximizedFlg == False:
        self.__maximizeWindow()

def __maximizeWindow(self):
    ***self.setWindowFlags(QtCore.Qt.CustomizeWindowHint)***
    screen = QtGui.QDesktopWidget().screenGeometry()
    self.setGeometry(screen)
    self.maximizedFlg = True

Having the marked line in __maximizeWindow outside of __init__ seems to make the window completely vanish. The application is still running (seen in task manager), but I can’t switch back to it using Alt+Tab or Task Manager.

How can I change Window Flags on fly?

Answer 1

From the Qt documentation on QWidget::windowFlags:

Note: This function calls setParent() when changing the flags for a window, causing the widget to be hidden. You must call show() to make the widget visible again.

So just add self.show() after self.setWindowFlags(...) and you’ll be fine.