On 4/27/07, Pradnyesh Sawant wrote:
> Hello, i have the following code:
> #################################################################
> import time
> import sys
> from PyQt4 import QtGui, QtCore
>
> class Counter(QtCore.QThread):
> def __init__(self):
> QtCore.QThread.__init__(self)
> def run(self):
> cntr = 0
> while cntr < 10:
> cntr += 1
> self.emit(QtCore.SIGNAL("showCntr1(PyObject*)"), (cntr,
> "a")) # line 1
> self.emit(QtCore.SIGNAL("showCntr2"), (cntr, "a"))
> # line 2
> time.sleep(0.2)
> class Gui(QtGui.QDialog):
> def __init__(self, parent = None):
> QtGui.QDialog.__init__(self, parent)
> frameStyle = QtGui.QFrame.Sunken | QtGui.QFrame.Panel
>
> self.lCntr = QtGui.QLabel()
> self.lCntr.setFrameStyle(frameStyle)
> loGrd = QtGui.QGridLayout()
> loGrd.addWidget(self.lCntr, 0, 0)
> self.setLayout(loGrd)
> self.setWindowTitle(self.tr("Counter"))
> def showCntr1(self, val):
> print val, str(val)
> self.lCntr.setText(str(val))
> def showCntr2(self, val):
> print val, str(val)
> self.lCntr.setText(str(val))
> if __name__ == "__main__":
> app = QtGui.QApplication(sys.argv)
> dialog = Gui()
> cntr = Counter()
> cntr.start()
> QtCore.QObject.connect(cntr, QtCore.SIGNAL("showCntr1(PyObject*)"),
> dialog.showCntr1, QtCore.Qt.QueuedConnection)
> QtCore.QObject.connect(cntr, QtCore.SIGNAL("showCntr2"),
> dialog.showCntr1, QtCore.Qt.QueuedConnection)
There's a small bug in the above line, it should be dialog.showCntr2,
and not dialog.showCntr1. However, even with this change, the output
shown below remains the same :(
> sys.exit(dialog.exec_())
> #################################################################
> If i comment out "line 1", then i get the following output:
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> 0.2 0.2
> Notice that 0.2 is the time value of the sleep instruction. Why is
> this happening?
>
> On the other hand, if i comment out "line 2", then i get the following output:
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> (<refcnt 0 at 0xb7dcd28c>, 'a') (<NULL>, <NULL>)
> What i get from the above is that a reference to "cntr" is being
> passed, but by the time the gui thread is actually run, both the
> values (cntr and "a") have been destroyed, hence the NULL values.
> ***How do i circumvent this problem?***
>
> Lastly, if i don't comment out any of line 1 or 2, then i get the foll output:
> (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui object at
> 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui
> object at 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>,
> (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui object at
> 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui
> object at 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>,
> (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui object at
> 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui
> object at 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>,
> (<__main__.Gui object at 0xb6a8f12c>, (<__main__.Gui object at
> 0xb6a8f12c>, (<__main__.Gui object at 0xb6a8f12c>, ..........
> i don't know what this means??? Can anyone kindly explain what's happening...
>
> I'm using:
> python: 2.4.4~c1-0ubuntu1
> qt4-dev-tools: not installed
> python-qt4: 4.0.1-1ubuntu1
> sip4: (4.4.5-2ubuntu1
> os: ubuntu edgy
> --
> warm regards,
> Pradnyesh Sawant
> --
> Be yourself, everyone else is taken. --Anon
>
--
warm regards,
Pradnyesh Sawant
--
Be yourself, everyone else is taken. --Anon
--
http://mail.python.org/mailman/listinfo/python-list
