Python上Qt中的QThread
作者：互联网
在阅读了有关应如何使用QThread的扩展讨论并通过子类覆盖它的run方法之后,我使用了一个Worker对象来使用QThread,这是不合适的方法.但是,在我打算使用的方法中,我需要传递一个附加的函数参数,该参数在线程启动以及使用moveToThread将工作程序推入线程时不可用.该信息(参数)在按下按钮时可用,并传达有关要移动的对象的信息.
在我的代码的完整版中,有3个单独的控制器,用于3个单独的对象,您可以在下面找到一个最小的工作示例,以说明我尝试传递参数的内容.该代码也可以在pastebin上使用,并且感兴趣的行号是10-28、46-50和133-135.
到目前为止,我已经尝试在连接到worker中实际函数的行中使用lambda构造函数.那行是self.thread.started.connect(self.obj.moveLeftIncrement)然后尝试使用插槽,但是我不太了解它们.此外,尽管使用了QThread,但有时GUI仍挂起,并且在程序退出后仍会出现错误,其中之一如下：
Process finished with exit code -1073740791 (0xC0000409)
我的问题如下：
>如何在运行时传递参数和/或使用插槽？
>如何防止退出时出现程序错误？
>为什么不推荐使用子类化QThread在这种情况下直接起作用？
from PySide2.QtCore import *
from PySide2.QtWidgets import *
from PySide2.QtGui import *
import sys
import time
class Worker(QObject):
finished = Signal(int)
@Slot(str)
def moveLeftIncrement(self, controller_name):
# controller_name = "Controller 1"
print("Controller name is ", controller_name)
if controller_name == "Controller 1":
print("Starting controller 1")
time.sleep(2)
print("Finishing sleep")
elif controller_name == "Controller 2":
print("Starting controller 2")
time.sleep(2)
print("Finishing sleep")
elif controller_name == "Controller 3":
print("Starting controller 3")
time.sleep(2)
print("Finishing sleep")
else:
raise Exception("No such controller found!")
self.finished.emit(0)
class Window(QWidget):
""" Inherits from QWidget """
def closeEvent(self, *args, **kwargs):
print("\nClosing")
def __init__(self):
super().__init__()
self.CONTINUOUS_MOVE_SWITCH = False
self.title = 'Control Controllers'
self.left = 10
self.top = 10
self.width = 320
self.height = 100
self.AxesMapping = [0, 1, 2, 3]
self.initUI()
self.thread = QThread()
self.obj = Worker()
self.obj.moveToThread(self.thread)
self.thread.started.connect(self.obj.moveLeftIncrement)
self.obj.finished.connect(self.thread.quit)
def initUI(self):
""" Initializes the GUI either using the grid layout or the absolute position layout"""
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
Comp1 = self.createGridLayout("Controller 2")
windowLayout = QGridLayout()
windowLayout.addWidget(Comp1, 0, 0)
self.setLayout(windowLayout)
self.show()
def createGridLayout(self, controller):
"""Creates a grid layout for the buttons"""
box_size = QSize(640, 440)
HGroupBox = QGroupBox(controller)
layout = QGridLayout()
layout.addWidget(self.createButton("left", controller), 2, 1)
layout.addWidget(self.createButton("right", controller), 2, 3)
layout.addWidget(self.createButton("forward", controller), 1, 2)
layout.addWidget(self.createButton("backward", controller), 3, 2)
HGroupBox.setLayout(layout)
HGroupBox.setFixedSize(box_size)
return HGroupBox
def createButton(self, name, controller):
"""Creates a button with the specified size"""
button_size = QSize(100, 40)
icon_size = 40
button = QPushButton()
button.Name = name
button.Controller = controller
button.Moving = 0
button.clicked.connect(lambda: self.buttonPresssed(button))
button.setFixedSize(button_size)
return button
def moveLeftIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
raise Exception("No such controller found!")
def moveRightIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
raise Exception("No such controller found!")
def moveForwardIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
raise Exception("No such controller found!")
def moveBackwardIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
raise Exception("No such controller found!")
def buttonPresssed(self, button):
name = button.Name
if hasattr(button, 'Controller'):
controller = button.Controller
print("The controller selected is", controller)
if name == 'left':
self.thread.start()
elif name == 'right':
print("Moved controller right for a single step")
self.moveRightIncrement(controller, button)
elif name == 'forward':
self.moveForwardIncrement(controller, button)
print("Moved controller forward for a single step")
elif name == 'backward':
self.moveBackwardIncrement(controller, button)
print("Moved controller backward for a single step")
elif name == "up":
print("Moving controller up for a single step")
self.moveUpIncrement(controller, button)
elif name == "down":
print("Moving controller down for a single step")
self.moveDownIncrement(controller, button)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Window()
sys.exit(app.exec_())
解决方法:
-如何在运行时传递参数和/或使用插槽？
如果要调用另一个线程中的对象的插槽,则必须使用信号,因为它是线程安全的.
-如何防止退出时出现程序错误？
在您的情况下,该错误是由于您正在运行一个线程而尚未停止它而引起的,一个可能的选择是使用closeEvent来停止它.
-为什么不推荐使用子类化QThread在这种情况下直接起作用？
并非不建议这样做,它是非常有限的,还有更好的选择,例如使用驻留在另一个线程中的工作程序,因此我们可以有不同的方法,而不仅仅是在run方法中执行任务.同样,通过worker的选择,您可以将多个对象置于一个线程中.
对于工人,方法如下：
>创建一个QThread并启动要处理的线程.
>创建一个将驻留在另一个线程中并移动另一个线程的对象
>连接调用对象插槽的信号,并连接将对象信息发送到GUI的信号.
>必要时发出它们将调用的信号.
考虑到上述情况,解决方案是：
from PySide2 import QtCore, QtGui, QtWidgets
import time
class Worker(QtCore.QObject):
error = QtCore.Signal()
@QtCore.Slot(str)
def moveLeftIncrement(self, controller):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
self.error.emit("No such controller found!")
@QtCore.Slot(str)
def moveRightIncrement(self, controller):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
self.error.emit("No such controller found!")
@QtCore.Slot(str)
def moveForwardIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
self.error.emit("No such controller found!")
@QtCore.Slot(str)
def moveBackwardIncrement(self, controller, button):
if controller == "Controller 1":
time.sleep(2)
elif controller == "Controller 2":
time.sleep(2)
elif controller == "Controller 3":
time.sleep(2)
else:
self.error.emit("No such controller found!")
class Window(QtWidgets.QWidget):
leftClicked = QtCore.Signal(str)
rightClicked = QtCore.Signal(str)
forwardClicked = QtCore.Signal(str)
backwardClicked = QtCore.Signal(str)
def __init__(self):
super().__init__()
self.CONTINUOUS_MOVE_SWITCH = False
self.title = 'Control Controllers'
self.left, self.top, self.width, self.height = 10, 10, 320, 100
self.AxesMapping = [0, 1, 2, 3]
self.initUI()
self.thread = QtCore.QThread(self)
self.thread.start()
self.obj = Worker()
self.obj.moveToThread(self.thread)
self.leftClicked.connect(self.obj.moveLeftIncrement)
self.rightClicked.connect(self.obj.moveRightIncrement)
self.forwardClicked.connect(self.obj.moveForwardIncrement)
self.backwardClicked.connect(self.obj.moveBackwardIncrement)
self.obj.error.connect(self.on_error)
def initUI(self):
self.setWindowTitle(self.title)
self.setGeometry(self.left, self.top, self.width, self.height)
Comp1 = self.createGridLayout("Controller 2")
windowLayout = QtWidgets.QGridLayout(self)
windowLayout.addWidget(Comp1, 0, 0)
def createGridLayout(self, controller):
"""Creates a grid layout for the buttons"""
box_size = QtCore.QSize(640, 440)
HGroupBox = QtWidgets.QGroupBox(controller)
layout = QtWidgets.QGridLayout()
layout.addWidget(self.createButton("left", controller), 2, 1)
layout.addWidget(self.createButton("right", controller), 2, 3)
layout.addWidget(self.createButton("forward", controller), 1, 2)
layout.addWidget(self.createButton("backward", controller), 3, 2)
HGroupBox.setLayout(layout)
HGroupBox.setFixedSize(box_size)
return HGroupBox
def createButton(self, name, controller):
button_size = QtCore.QSize(100, 40)
icon_size = 40
button = QtWidgets.QPushButton()
button.Name = name
button.Controller = controller
button.Moving = 0
button.clicked.connect(self.buttonPresssed)
button.setFixedSize(button_size)
return button
@QtCore.Slot()
def buttonPresssed(self):
button = self.sender()
name = button.Name
if hasattr(button, 'Controller'):
controller = button.Controller
print("The controller selected is", controller)
if name == 'left':
self.leftClicked.emit(controller)
elif name == 'right':
print("Moved controller right for a single step")
self.rightClicked.emit(controller)
elif name == 'forward':
print("Moved controller forward for a single step")
self.forwardClicked.emit(controller)
elif name == 'backward':
print("Moved controller backward for a single step")
self.backwardClicked.emit(controller)
@QtCore.Slot(str)
def on_error(self, error):
print(error)
def closeEvent(self, event):
self.thread.quit()
self.thread.wait()
super(Window, self).closeEvent(event)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
ex = Window()
ex.show()
sys.exit(app.exec_())
标签：multithreading,python-3-x,qthread,pyside2,python 来源： https://codeday.me/bug/20191211/2106669.html