工作线程和主线程 window 之间的 PyQt5 信号通信工作不正常

Question

我正在使用 PyQt5 创建一个应用程序，它具有非常简单的用户界面。有一个可以从中选择值的下拉列表，然后有一个可以单击的按钮，将根据下拉列表中的当前值执行操作。

目前，如果我运行下面的代码，我可以从下拉列表中获取一个值，它会在 myaction.myaction(customer_name) 为运行之前发送到工作线程。代码也运行s 很好，但是当工作线程中的函数运行s 时，GUI 没有按照我希望的方式工作。当我单击 start 按钮时，它应该向 GUI 发出信号以禁用该按钮，更改其标签和颜色，但这种情况从未发生过。当函数完成后，它应该变回原来的形式。

是我处理信号的方式有问题，还是我的类中有冗余功能？每次单击按钮时将该下拉列表值发送到工作线程的正确方法是什么，这样我就可以简单地将它用作那里的变量？

我在网上找到的每一个可能的解决方案都让我很兴奋，但是 none 中的一些已经为我工作，或者其中一些太混乱了我无法理解。

这是我已经完成的一些答案

Sending a signal from main function to a thread?

#!/usr/bin/env python3

import sys
#import myaction
import time
from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QComboBox, QLabel
from PyQt5 import QtCore

class ConfWorker(QtCore.QThread):
    updated_button = QtCore.pyqtSignal(list)
    updated_label = QtCore.pyqtSignal(str)
    updated_error = QtCore.pyqtSignal(str)
    request_signal = QtCore.pyqtSignal()
    customer = QtCore.pyqtSignal(str)

    def __init__(self, parent=None):
        super(ConfWorker, self).__init__(parent)
        self.customer.connect(self.getcustomer)

    def run(self):
        self.request_signal.emit()

    def getcustomer(self, text):
        self.configure(text)

    def configure(self, customer_name):
        self.updated_button.emit(["In progress...", False])
        self.updated_label.emit(customer_name)
        time.sleep(5) # During this time you should be able to see color change etc.
        #myaction.myaction(customer_name)# TAKES ~20 SECONDS TO FINISH
        self.updated_button.emit(["Start", True])

class ConfGUI(QWidget):
    def __init__(self, parent=None):
        super(ConfGUI, self).__init__()

        self.worker = ConfWorker(self)
        self.worker.updated_button.connect(self.updateButton)
        self.worker.updated_label.connect(self.updateLabel)
        self.worker.updated_error.connect(self.updateError)
        self.worker.request_signal.connect(self.sendCustomer)

        self.targetBtn = QPushButton('Start Configuration', self)
        self.targetBtn.setStyleSheet("QPushButton { background-color: green; color: white }"
                        "QPushButton:disabled { background-color: red; color: white }")
        self.targetBtn.clicked.connect(self.worker.start)
        self.targetBtn.setGeometry(100, 400, 200, 50)
        self.setGeometry(800, 300, 400, 550)
        self.setFixedSize(400, 550)

        self.customerlist = QComboBox(self)
        self.customerlist.setGeometry(100, 50, 200, 50)
        self.customerlist.setObjectName("customer")
        self.customerlist.addItem("testcustomer1")
        self.customerlist.addItem("testcustomer2")
        self.customerlist.addItem("testcustomer3")

        self.label = QLabel(self)
        self.label.setText("")
        self.label.setStyleSheet('font-size: 30pt; font-family: Courier; color: green;')
        self.label.setGeometry(70,250,400,50)

        self.error_label = QLabel(self)
        self.error_label.setText("")
        self.error_label.setStyleSheet('font-size: 30pt; font-family: Courier; color: red;')
        self.error_label.setGeometry(70,350,400,50)

        self.show()

    def sendCustomer(self):
        self.worker.customer.emit(self.customerlist.currentText())

    def updateButton(self, button_list):
        self.targetBtn.setText(button_list[0])
        self.targetBtn.setEnabled(button_list[1])

    def updateLabel(self, label_text):
        self.label.setText(label_text)

    def updateError(self, error_text):
        self.error_label.setText(error_text)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = ConfGUI()
    sys.exit(app.exec_())

Answer 1

你真的写出非常难的简单东西。试一试：

import sys
from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QComboBox, QLabel
from PyQt5.QtCore    import QThread, pyqtSignal

class ConfWorker(QThread):
    threadSignal = pyqtSignal(str)
    finishSignal = pyqtSignal(str)

    def __init__(self, startParm):
        super().__init__()
        self.startParm = startParm   # Initialize the parameters passed to the task 

    def run(self):
        # Do something...
        for i in range(20):
            text = "In progress ................." \
                    if i%2==0 else "In progress {}".format(self.startParm)
            self.threadSignal.emit(text)
            QThread.msleep(500)
        self.finishSignal.emit(self.startParm)


class ConfGUI(QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(800, 100, 400, 550)
        self.setFixedSize(400, 550)        

        self.targetBtn = QPushButton('Start Configuration', self)
        self.targetBtn.setStyleSheet(
                        "QPushButton { background-color: green; color: white;}"
                        "QPushButton:disabled { background-color: red; color: white;}"
                        )
        self.targetBtn.setGeometry(100, 400, 200, 50)
        self.targetBtn.clicked.connect(self.workerStart)           

        self.customerlist = QComboBox(self)
        self.customerlist.setGeometry(100, 50, 200, 50)
        self.customerlist.setObjectName("customer")
        self.customerlist.addItem("testcustomer1")
        self.customerlist.addItem("testcustomer2")
        self.customerlist.addItem("testcustomer3")
        self.customerlist.activated[str].connect(self.comboActivated)
        self.startParm = "testcustomer1"

        self.label = QLabel(self)
        self.label.setStyleSheet('font-size: 30pt; font-family: Courier; color: green;')
        self.label.setGeometry(70,250,400,50)

    def workerStart(self):
        self.targetBtn.setText("In progress...")
        self.targetBtn.setEnabled(False)
        self.label.setText("")
        self.worker = ConfWorker(self.startParm)  
        self.worker.threadSignal.connect(self.on_threadSignal)
        self.worker.finishSignal.connect(self.on_finishSignal)        
        self.worker.start()                     

    def on_threadSignal(self, text):
        self.targetBtn.setText(text)

    def on_finishSignal(self, text):
        self.targetBtn.setEnabled(True)
        self.targetBtn.setText("Start Configuration'")
        self.label.setText(text)

    def comboActivated(self, text):
        self.startParm = text


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex  = ConfGUI()
    ex.show()
    sys.exit(app.exec_())

Answer 2

这个问题是一个很普遍的错误观念造成的，他们认为QThread是一个Qt Thread，也就是Qt新建的线程，但是不是，QThread 是线程 handler，如 the docs:

所示

The QThread class provides a platform-independent way to manage threads.

A QThread object manages one thread of control within the program. QThreads begin executing in run(). By default, run() starts the event loop by calling exec() and runs a Qt event loop inside the thread.

另一个线程上运行的唯一部分是运行方法，在你的情况下你没有调用，因为你的逻辑不同，你不想连续执行一个沉重的任务，但应用户要求，因此设计必须是工人的设计，但您使用 QThread 作为基础 class，这是不正确的，您必须使用 QObject 作为基础 class 并移动它到一个新线程，以便 QObject 在该线程中执行其任务，防止 GUI 阻塞。

一个QObject不是线程安全的，它存在于一个线程中，而它所在的线程由以下决定：

一个QObject住在父线程
如果你没有父线程，除非你已经移动到另一个线程，否则就住在创建它的线程中。
并且您可以使用 moveToThread() 函数移动到另一个线程，但是如果 QObject 有父线程，moveToThread() 将失败，因为第一个条件是特权.

另一方面，如果您想从另一个线程调用方法，则必须使用装饰器 @QtCore.pyqtSlot()

综上所述，得到如下解法：

#!/usr/bin/env python3
import sys
import time
from PyQt5 import QtCore, QtWidgets


class ConfWorker(QtCore.QObject):
    updated_button = QtCore.pyqtSignal(list)
    updated_label = QtCore.pyqtSignal(str)
    updated_error = QtCore.pyqtSignal(str)
    request_signal = QtCore.pyqtSignal()
    customer = QtCore.pyqtSignal(str)

    def __init__(self, parent=None):
        super(ConfWorker, self).__init__(parent)
        self.customer.connect(self.getcustomer)

    @QtCore.pyqtSlot()
    def doWork(self):
        self.request_signal.emit()

    @QtCore.pyqtSlot(str)
    def getcustomer(self, text):
        self.configure(text)

    def configure(self, customer_name):
        self.updated_button.emit(["In progress...", False])
        self.updated_label.emit(customer_name)
        time.sleep(5) # During this time you should be able to see color change etc.
        #myaction.myaction(customer_name)# TAKES ~20 SECONDS TO FINISH
        self.updated_button.emit(["Start", True])

class ConfGUI(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ConfGUI, self).__init__()

        # create a QThread and start the thread that handles
        thread = QtCore.QThread(self)
        thread.start()

        # create the worker without a parent so you can move
        self.worker = ConfWorker()
        # the worker moves to another thread
        self.worker.moveToThread(thread)

        self.worker.updated_button.connect(self.updateButton)
        self.worker.updated_label.connect(self.updateLabel)
        self.worker.updated_error.connect(self.updateError)
        self.worker.request_signal.connect(self.sendCustomer)

        self.targetBtn = QtWidgets.QPushButton('Start Configuration', self)
        self.targetBtn.setStyleSheet("QPushButton { background-color: green; color: white }"
                        "QPushButton:disabled { background-color: red; color: white }")
        self.targetBtn.clicked.connect(self.worker.doWork)
        self.targetBtn.setFixedSize(200, 50)

        self.customerlist = QtWidgets.QComboBox(self)
        self.customerlist.addItems(["testcustomer1", "testcustomer2", "testcustomer3"])
        self.customerlist.setFixedSize(200, 50)

        self.label = QtWidgets.QLabel(self, alignment=QtCore.Qt.AlignCenter)
        self.label.setStyleSheet('font-size: 30pt; font-family: Courier; color: green;')
        self.label.setFixedSize(400,50)

        self.error_label = QtWidgets.QLabel(self, alignment=QtCore.Qt.AlignCenter)
        self.error_label.setStyleSheet('font-size: 30pt; font-family: Courier; color: red;')
        self.error_label.setFixedSize(400,50)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.customerlist, alignment=QtCore.Qt.AlignCenter)
        lay.addWidget(self.label, alignment=QtCore.Qt.AlignCenter)
        lay.addWidget(self.error_label, alignment=QtCore.Qt.AlignCenter)
        lay.addWidget(self.targetBtn, alignment=QtCore.Qt.AlignCenter)
        self.setFixedSize(400, 550)

    @QtCore.pyqtSlot()
    def sendCustomer(self):
        self.worker.customer.emit(self.customerlist.currentText())

    @QtCore.pyqtSlot(list)
    def updateButton(self, button_list):
        self.targetBtn.setText(button_list[0])
        self.targetBtn.setEnabled(button_list[1])

    @QtCore.pyqtSlot(str)
    def updateLabel(self, label_text):
        self.label.setText(label_text)

    @QtCore.pyqtSlot(str)
    def updateError(self, error_text):
        self.error_label.setText(error_text)


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    ex = ConfGUI()
    ex.show()
    sys.exit(app.exec_())

观察： 另外，正如您在我的解决方案中看到的那样，QThread 将是 window 的子代，因为 QThread是处理另一个线程的 QObject。

工作线程和主线程 window 之间的 PyQt5 信号通信工作不正常

PyQt5 signal communication between worker thread and main window is not working correctly

python

multithreading

pyqt

qthread

pyqt5