如何从另一个python文件调用Qt线程(QThread) ?(QThread被销毁)

Question

如何调用在另一个python文件中定义的QThread ?

这是我的代码。

mymain.py

from PyQt4 import QtCore, QtGui
import PyQt4
import sys
import os
from time import sleep
try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
_    fromUtf8 = lambda s: s
class Ui_MainWindow(QtGui.QMainWindow):
  def __init__(self):
       QtGui.QWidget.__init__(self)
       self.setupUi(self)
  def setupUi(self, MainWindow):
       MainWindow.setObjectName(_fromUtf8("MainWindow"))
       self.showMaximized()
       MainWindow.setStyleSheet(_fromUtf8("background-color: rgb(0, 0, 0);"))
       self.centralwidget = QtGui.QWidget(MainWindow)
       self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
       self.horizontalLayout = QtGui.QHBoxLayout(self.centralwidget)
       self.horizontalLayout.setObjectName(_fromUtf8("horizontalLayout"))
       self.gridLayout = QtGui.QGridLayout()
       self.gridLayout.setObjectName(_fromUtf8("gridLayout"))
       spacerItem = QtGui.QSpacerItem(20, 40, QtGui.QSizePolicy.Minimum, QtGui.QSizePolicy.Expanding)
       self.gridLayout.addItem(spacerItem, 2, 0, 1, 1)
       self.horizontalLayout_2 = QtGui.QHBoxLayout()
       self.horizontalLayout_2.setObjectName(_fromUtf8("horizontalLayout_2"))
       self.verticalLayout = QtGui.QVBoxLayout()
       self.verticalLayout.setObjectName(_fromUtf8("verticalLayout"))
       self.lblNowServing = QtGui.QLabel(self.centralwidget)
       font = QtGui.QFont()
       font.setFamily(_fromUtf8("Bebas Neue"))
       font.setPointSize(140)
       self.lblNowServing.setFont(font)
       self.lblNowServing.setStyleSheet(_fromUtf8("color: rgb(170, 0, 0);"))
       self.lblNowServing.setObjectName(_fromUtf8("lblNowServing"))
       self.lblNowServing.setAlignment(QtCore.Qt.AlignCenter)
       self.verticalLayout.addWidget(self.lblNowServing)
       self.lblNowServingNumber = QtGui.QLabel(self.centralwidget)
       font = QtGui.QFont()
       font.setFamily(_fromUtf8("DS-Digital"))
       font.setPointSize(350)
       self.lblNowServingNumber.setFont(font)
       self.lblNowServingNumber.setStyleSheet(_fromUtf8("color: rgb(170, 0, 0);"))
       self.lblNowServingNumber.setObjectName(_fromUtf8("lblNowServingNumber"))
       self.lblNowServingNumber.setAlignment(QtCore.Qt.AlignCenter)
       self.verticalLayout.addWidget(self.lblNowServingNumber)
       self.horizontalLayout_2.addLayout(self.verticalLayout)
       self.verticalLayout_2 = QtGui.QVBoxLayout()
       self.verticalLayout_2.setObjectName(_fromUtf8("verticalLayout_2"))
       self.lblCounter = QtGui.QLabel(self.centralwidget)
       font = QtGui.QFont()
       font.setFamily(_fromUtf8("Bebas Neue"))
       font.setPointSize(140)
       self.lblCounter.setFont(font)
       self.lblCounter.setStyleSheet(_fromUtf8("color: rgb(170, 0, 0);"))
       self.lblCounter.setObjectName(_fromUtf8("lblCounter"))
       self.lblCounter.setAlignment(QtCore.Qt.AlignCenter)
       self.verticalLayout_2.addWidget(self.lblCounter)
       self.lblCounterNumber = QtGui.QLabel(self.centralwidget)
       font = QtGui.QFont()
       font.setFamily(_fromUtf8("DS-Digital"))
       font.setPointSize(350)
       self.lblCounterNumber.setFont(font)
       self.lblCounterNumber.setStyleSheet(_fromUtf8("color: rgb(170, 0, 0);"))
       self.lblCounterNumber.setObjectName(_fromUtf8("lblCounterNumber"))
       self.lblCounterNumber.setAlignment(QtCore.Qt.AlignCenter)
       self.verticalLayout_2.addWidget(self.lblCounterNumber)
       self.horizontalLayout_2.addLayout(self.verticalLayout_2)
       self.gridLayout.addLayout(self.horizontalLayout_2, 0, 0, 1, 1)
       spacerItem = QtGui.QSpacerItem(20, 40, QtGui.QSizePolicy.Minimum, QtGui.QSizePolicy.Expanding)
       self.gridLayout.addItem(spacerItem, 1, 0, 1, 1)
       self.horizontalLayout.addLayout(self.gridLayout)
       MainWindow.setCentralWidget(self.centralwidget)
       self.retranslateUi(MainWindow)
       QtCore.QMetaObject.connectSlotsByName(MainWindow)
   def retranslateUi(self, MainWindow):
       MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "MainWindow", None, QtGui.QApplication.UnicodeUTF8))
       self.lblNowServing.setText(QtGui.QApplication.translate("MainWindow", "  NOW SERVING  ", None, QtGui.QApplication.UnicodeUTF8))
       self.lblCounter.setText(QtGui.QApplication.translate("MainWindow", "COUNTER", None, QtGui.QApplication.UnicodeUTF8))        
       self.lblCounterNumber.setText(str(1))
       self.lblNowServingNumber.setText(str(1))
class valChange(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)
    def run(self):
        self.myctr = 0
        self.myval = 0
        self.lblNowServingNumber.setText(str(myval))
        self.lblCounterNumber.setText(str(myctr))            
if __name__=='__main__':
    app = QtGui.QApplication(sys.argv)
    ex = Ui_MainWindow()
    ex.show()
    sys.exit(app.exec_())

exarg.py

from PyQt4 import QtCore, QtGui
import mymain
import sys, getopt
def main(argv):
 ctr = ''
 val = ''
 try:
    opts, args = getopt.getopt(argv,"hi:o:",["ifile=","ofile="])
 except getopt.GetoptError:
    print 'test.py -i <ctr> -o <val>'
    sys.exit(2)
 for opt, arg in opts:
    if opt == '-h':
       print 'test.py -i <ctr> -o <val>'
       sys.exit()
    elif opt in ("-i", "--ifile"):
       ctr = arg
    elif opt in ("-o", "--ofile"):
       val = arg
  m = mymain.valChange()
  m.myctr = ctr
  m.myval = val
  m.start()
if __name__ == "__main__":
 app = QtGui.QApplication(sys.argv)
 main(sys.argv[1:])

这就是我所做的，我在shell中运行mymain.py。我在终端/命令行中运行exarg.py，使用以下命令

sudo python exarg.py -i 3 - 0 4

但是我总是得到一个错误说:

'QThread:在线程还在运行时被销毁'

任何意见/建议都将非常感谢。谢谢。

Answer 1

您的代码目前存在一些问题。

首先，您似乎没有在任何地方调用app.exec_()(至少当您运行exarg.py时)来实际启动您的QApplication。但也许你只是忘了说这一点?

第二种方法是在函数中创建线程，并将其赋值给变量m。一旦函数main结束，该局部变量将被垃圾收集，线程将被销毁。你要确保这不会发生。通过使m成为一个全局变量，或者从函数返回m并保存对它的引用，或者您不能在函数中创建它。只要您始终持有对线程的引用，它就不会被销毁，您就不会看到错误消息!

最后，您应该永远不要直接从线程修改GUI对象。Qt小部件不是线程安全的!您需要做的是在线程中定义一个信号，并在创建线程时将插槽(从主线程)连接到该信号。然后你可以emit一个来自线程的信号(这是线程安全的)，它将调用主线程中的一个插槽，在那里你可以修改GUI。这个问题/答案大致演示了如何做到这一点。

编辑:另外，global myctr等代码令人困惑。你不需要这个。在调用m.start()之前，您已经编写了m.myctr = ctr，因此只需从线程内访问它们作为self.myctr。