Hi,
I have a threaded program which works fine under Linux, but crashes sometimes
under Windows. My suspicion is that this is because I use
QtCore.QCoreApplication.processEvents, for which I read everywhere that this
is to be avoided and is a crutch for poor design.
Also, many tutorial examples don't seem to require processEvents, but in my
case, slots in the GUI main thread don't soom to get called unless I use
processEvents.
I'm obviously missing something about threads and Qt here, but can somebody
have a look at my code and see what is going wrong?
Thanks!
Peter
import sys
import time
from PyQt4 import QtCore, QtGui
class Worker(QtCore.QObject):
update_progress_signal = QtCore.pyqtSignal(int)
finished_signal = QtCore.pyqtSignal()
def __init__(self):
QtCore.QObject.__init__(self)
def do_work(self):
for i in range(6):
self.update_progress_signal.emit(i)
print 'signal emitted', i
time.sleep(1) # Stand-in for doing some heavy work.
self.finished_signal.emit()
class Server(QtCore.QObject):
def __init__(self, widget):
QtCore.QObject.__init__(self)
self.progress_bar = QtGui.QProgressDialog(widget)
self.progress_bar.setRange(0, 5)
worker = Worker()
thread = QtCore.QThread()
worker.moveToThread(thread)
thread.started.connect(worker.do_work)
worker.update_progress_signal.connect(self.show_progress)
worker.finished_signal.connect(thread.quit)
thread.start()
working_version = True
if working_version:
while thread.isRunning():
QtCore.QCoreApplication.processEvents(\
QtCore.QEventLoop.ExcludeUserInputEvents)
thread.wait(100)
else:
thread.wait()
def show_progress(self, i):
print 'slot called', i
self.progress_bar.setValue(i)
app = QtGui.QApplication(sys.argv)
widget = QtGui.QWidget()
widget.resize(250, 150)
widget.setWindowTitle('Thread test')
widget.show()
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