QPaintDevice: Must construct a QApplication before a QPaintDevice

[Phil Thompson]

On Wednesday 28 February 2007 9:26 am, boris.smirnov at gmail.com wrote:
> On Feb 28, 10:22 am, Phil Thompson <p... at riverbankcomputing.co.uk>
>
> wrote:
> > On Wednesday 28 February 2007 9:00 am, boris.smir... at gmail.com wrote:
> > > On Feb 28, 9:07 am, boris.smir... at gmail.com wrote:
> > > > On Feb 28, 8:56 am, Phil Thompson <p... at riverbankcomputing.co.uk>
> > > >
> > > > wrote:
> > > > > On Tuesday 27 February 2007 11:09 pm, shredwheat wrote:
> > > > > > When your programs stops with the error, it should also be
> > > > > > printing a stack trace. This is a list of all the functions that
> > > > > > have been called when Python had the problem.
> > > > > >
> > > > > > You shouldn't have to do anything extra to get the stack trace.
> > > > >
> > > > > The error is raised in Qt and aborts immediately. It never gets
> > > > > back to Python to generate a trace.
> > > > >
> > > > > He needs to produce a short and complete test which demonstrates
> > > > > the problem, then we can point out where the QPaintDevice is being
> > > > > created.
> > > > >
> > > > > Phil
> > > >
> > > > OK, but before I do a complete test, could anybody tell/explain me
> > > > why the same file is working on Windows?
> > > > Did anybody already meet with something similar Win vs. Linux?
> > > >
> > > > b.
> > >
> > > Here is my simple script:
> > >
> > > import sys
> > > from qt import *
> > > class Optimizer(QWidget):
> > >    def __init__(self, parent = 0):
> > >       QWidget.__init__(self)
> > >       QGridLayout(self)
> > > if __name__ == '__main__':
> > >    a = QApplication (sys.argv)
> > >    mywidget = Optimizer()
> > >    a.exec_loop()
> > >
> > > This produces this:
> > > > python qt_script_bs_070228.py
> > >
> > > QPaintDevice: Must construct a QApplication before a QPaintDevice
> > >
> > > Any suggestions here?
> >
> > It works fine for me.
> >
> > > Thanks
> > >
> > > BTW: One question:
> > > when I use "import qt" instead of "from qt import *" I get this error:
> > > Traceback (most recent call last):
> > >   File "mscarideidtool_bs_070228.py", line 4, in ?
> > >     class Optimizer(QWidget):
> > > NameError: name 'QWidget' is not defined
> > >
> > > What is the difference between "import qt" and "from qt import *" ? I
> > > thought that these are the same.
> >
> > The first creates a new namespace called "qt" and imports the module's
> > objects into it. To reference those objects you have to include the
> > namespace name.
> >
> > The second imports the module's objects into the current namespace.
> >
> > Phil- Hide quoted text -
> >
> > - Show quoted text -
>
> OK, I have to apologize because I didn't mention that I use python
> version 2.2.1, could it be the problem here? Bugs or something? I have
> to use this version since it was delivered with a software that we use
> here.

So what versions of Qt, PyQt and SIP are you using? Were these included with 
the software you are using? If so, what is that software?

Phil