标签：multithreading python-3-x qthread pyside2 python

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

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