Multithreading in PyQt

	from PyQt4 import QtCore, QtGui
	from mainui import MainUI
	import time
	from hardware_controller import Hardware_Controller
	class Worker(QtCore.QThread):
	update_text_signal = QtCore.pyqtSignal(str) #have to pass the type str
	def __init__(self, hdwr_ctrl, update_rate):
	QtCore.QThread.__init__(self)
	self.hdwr_ctrl = hdwr_ctrl
	self.update_rate = update_rate
	self.running = True
	self.controller_num = 1
	def run(self):
	while(self.running):
	text = self.hdwr_ctrl.get_important_text(self.controller_num)
	update_text_signal.emit(text)
	time.sleep(self.update_rate)
	@QtCore.pyqtSlot(int)
	def change_controller_num(self,i):
	"""
	Change the controller number from the spin box in the UI.
	"""
	self.controller_num = i
	class MainWindow(QtGui.QMainWindow):
	def __init__(self, parent=None):
	QtGui.QMainWindow.__init__(self,parent)
	self.ui = MainUI # contains a bunch of widget definitions we don't care about
	self.ui.setUpUi(self)
	self.__connect()
	def __connect(self):
	self.hdwr_ctrl = Hardware_Controller()
	self.worker = Worker(self.hdwr_ctrl,1)
	self.worker.update_text_signal.connect(self.update_text)
	QtCore.QObject.connect(self.ui.spinbox, QtCore.SINGAL("valueChanged(int)"), self.worker.change_controller_num)
	self.worker.start()
	# so we can close the program
	self.connect(self, QtCore.SIGNAL('triggered()'), self.closeEvent)
	def update_text(self, text):
	"""
	Callback for the worker.update_text_signal pyqtSignal
	"""
	self.ui.textBox.setText(text)
	def closeEvent(self):
	"""
	Safely shut down worker threads.
	"""
	self.worker.running = False
	self.worker.quit()
	self.worker.wait()
	if __name__ == '__main__':
	app = QtGui.QApplication(sys.argv)
	GUI = MainWindow()
	GUI.show()
	sys.exit(app_exec_())

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