python - Multiple windows in PyQt4? -
i've begun using pyqt4. followed tutorial (http://zetcode.com/tutorials/pyqt4/) 1 thing puzzles me part:
def main(): app = qtgui.qapplication(sys.argv) ex = gui() sys.exit(app.exec()) and reason explain here:
i have made small program opens 4 more windows except first main window. tried replicate saw worked main-window , created class every new window , tried above. looks this:
def main2(): #app = qtgui.qapplication(sys.argv) ex2 = settings() sys.exit(app.exec()) as can see have modified it. if left first line in function uncommented program crash. tried without sys.exit(app.exec_())-part make new window close milliseconds after showed. way though, runs , works. in command window, error message displays. don't know how fix this, since cannot remove last line, , dont't know replace "app" with.
i know i'm doing new windows wrong beginning, don't know how make these windows open original window in other way. haven't been able else work, , @ least runs , works right now. problem error messages in prompt, nice rid of them :)
thanks (complicated , easy ones)!
forgot mention, made classes start this:
class gui(qtgui.qmainwindow): def __init__(self): super(gui, self).__init__() self.initui() and
class settings(qtgui.qwidget): def __init__(self): super(settings, self).__init__() ...here goes more... self.initui2() and open settings-window calling main2()
you must create 1 , 1 qapplication in program.
keep in mind gui programming event-driven, first declare widgets , run main loop app.exec(), when user quit application, app.exec() returns.
the qapplication purpose handle user events , propagate them code qt signals. suggest check qt documentation, it's complete, if it's targetting c++ programmers.
so instance, way create 2 widgets be:
def main(): app = qtgui.qapplication(sys.argv) ex = qtgui.qwidget() ex.show() ex2 = qtgui.qwidget() ex2.show() sys.exit(app.exec()) 
