python - QObject::setParent:无法设置父级，新父级位于Python中的不同线程中

标签 python python-3.x multithreading pyqt pyqt5

我使用 PyQt5 开发的 GUI 遇到问题。

应用尝试从不同的线程更新窗口进度条的值(QThreadPool())。当它尝试更新进度条时，Python 会发出如下警告:

QObject::setParent: Cannot set parent, new parent is in a different thread

这在一定程度上不会影响应用程序，但一段时间后应用程序会崩溃并显示以下错误消息。

QBackingStore::endPaint() called with active painter on backingstore paint device

有人可以帮我摆脱第一个警告吗？我想这会解决问题。

我将发布代码的最小示例。

main.py

import sys
from PyQt5.QtCore import *
from PyQt5 import QtCore, QtGui, QtWidgets
import thread_for_audio_record
import time


class FW(object):
    def __init__(self):
        self.threadpool = QThreadPool()

    def f_w(self, window):
        self.window = window
        self.window.setObjectName("Test")
        self.window.resize(1054, 700)
        self.window.setStyleSheet("background-color: rgb(180, 180, 180);")
        self.central_widget = QtWidgets.QWidget(self.window)
        self.central_widget.setObjectName("centralwidget")
        self.horizontal_layout = QtWidgets.QHBoxLayout(self.central_widget)
        self.horizontal_layout.setObjectName("horizontalLayout")
        spacer_item = QtWidgets.QSpacerItem(129, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontal_layout.addItem(spacer_item)
        self.vertical_layout = QtWidgets.QVBoxLayout()
        self.vertical_layout.setObjectName("verticalLayout")
        spacer_item_1 = QtWidgets.QSpacerItem(128, 13, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.vertical_layout.addItem(spacer_item_1)
        self.label_utterance = QtWidgets.QLabel(self.central_widget)
        font = QtGui.QFont()
        font.setPointSize(15)
        font.setBold(True)
        font.setBold(True)
        font.setWeight(75)
        self.label_utterance.setFont(font)
        self.label_utterance.setAlignment(QtCore.Qt.AlignCenter)
        self.label_utterance.setObjectName("label_utterance")
        self.vertical_layout.addWidget(self.label_utterance)
        self.text_edit_utterance = QtWidgets.QTextEdit(self.central_widget)
        self.text_edit_utterance.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.text_edit_utterance.setObjectName("text_edit_utterance")
        self.text_edit_utterance.setReadOnly(True)
        self.text_edit_utterance.setFont(font)
        self.vertical_layout.addWidget(self.text_edit_utterance)
        self.line_edit_message_for_user = QtWidgets.QLineEdit(self.central_widget)
        self.line_edit_message_for_user.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.line_edit_message_for_user.setObjectName("lineEdit")
        self.progressBar = QtWidgets.QProgressBar(self.central_widget)
        self.progressBar.setProperty("value", 0)
        self.progressBar.setObjectName("progressBar")
        self.vertical_layout.addWidget(self.progressBar)
        self.vertical_layout.addWidget(self.line_edit_message_for_user)
        self.push_button_start_recording = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_start_recording.setFont(font)
        self.push_button_start_recording.setStyleSheet("background-color: rgb(85, 170, 0);")
        self.push_button_start_recording.setObjectName("pushButton_start_
                                                           recording")

        self.push_button_start_recording.clicked.connect(self.start_button_
                                                               func)
        self.vertical_layout.addWidget(self.push_button_start_recording)
        self.push_button_end_recording = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_end_recording.setFont(font)
        self.push_button_end_recording.setStyleSheet("background-color: rgb(182, 0, 0);")
        self.push_button_end_recording.setObjectName("pushButton_end_
                                                        recording")
        self.vertical_layout.addWidget(self.push_button_end_recording)
        self.label_status = QtWidgets.QLabel(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.label_status.setFont(font)
        self.label_status.setObjectName("label_status")
        self.vertical_layout.addWidget(self.label_status)
        self.text_edit_status = QtWidgets.QTextEdit(self.central_widget)
        self.text_edit_status.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.text_edit_status.setObjectName("textEdit_status")
        self.text_edit_status.setReadOnly(True)
        self.vertical_layout.addWidget(self.text_edit_status)
        self.push_button_record_again = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_record_again.setFont(font)
        self.push_button_record_again.setStyleSheet("background-color: rgb(255, 255, 127);")
        self.push_button_record_again.setObjectName("pushButton_record_
                                                               again")
        self.vertical_layout.addWidget(self.push_button_record_again)
        self.push_button_next_utterance = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_next_utterance.setFont(font)
        self.push_button_next_utterance.setStyleSheet("background-color: rgb(85, 170, 0);")
        self.push_button_next_utterance.setObjectName("pushButton_next_
                                                         utterance")
        self.vertical_layout.addWidget(self.push_button_next_utterance)
        spacer_item_2 = QtWidgets.QSpacerItem(128, 13, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.vertical_layout.addItem(spacer_item_2)
        self.horizontal_layout.addLayout(self.vertical_layout)
        spacer_item_3 = QtWidgets.QSpacerItem(128, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontal_layout.addItem(spacer_item_3)
        self.window.setCentralWidget(self.central_widget)
        self.menubar = QtWidgets.QMenuBar(self.window)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 1054, 21))
        self.menubar.setObjectName("menubar")
        self.window.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(self.window)
        self.statusbar.setObjectName("statusbar")
        self.window.setStatusBar(self.statusbar)
        self.retranslate_ui(self.window)
        QtCore.QMetaObject.connectSlotsByName(self.window)

    def retranslate_ui(self, window):

        _translate = QtCore.QCoreApplication.translate
        window.setWindowTitle(_translate("Utterance Recording", "Test"))
        self.label_utterance.setText(_translate("Utterance Recording", "Test"))
        self.line_edit_message_for_user.setText(_translate("Utterance Recording", "Test."))
        self.text_edit_utterance.setText(_translate("utterance_parsing", ('Test')))
        self.push_button_start_recording.setText(_translate("Utterance Recording", "Start Recording"))
        self.push_button_end_recording.setText(_translate("Utterance Recording", "End Recording"))
        self.label_status.setText(_translate("Utterance Recording", "Test"))
        self.push_button_record_again.setText(_translate("Utterance Recording", "Test"))
        self.push_button_next_utterance.setText(_translate("Utterance Recording", "Test"))

    def inside_thread(self):
        percentage = 0
        while percentage < 120:
            percentage = percentage + 20
            time.sleep(0.2)
            self.progressBar.setValue(percentage)

    def start_button_func(self):
        self.worker = thread_for_audio_record.Worker(self.inside_thread)
        self.threadpool.start(self.worker)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    utterance_parsing_window = QtWidgets.QMainWindow()
    utterance_parsing = FW()
    utterance_parsing.f_w(utterance_parsing_window)
    utterance_parsing_window.show()
    sys.exit(app.exec_())

thread_for_audio_record.py

import os
from PyQt5.QtCore import *


class Worker(QRunnable):

    def __init__(self, fn):
        super(Worker, self).__init__()
        self.fn = fn
        self.originating_PID = os.getpid()
        self._running = True

    @pyqtSlot()
    def run(self):
        self.fn()

单击开始录制按钮，您将看到进度条正在更新。但给出警告消息是因为更新来自不同的线程。

最佳答案

首先，不要按照 PyQt 的建议修改 Qt Designer 生成的代码，而是创建另一个从适当的小部件继承的类，并使用初始类作为接口(interface)。

言归正传，Qt 不允许直接从另一个线程更新 GUI，在您的情况下，在辅助线程中调用 QProgressBar 的 setValue 导致在 secuandario 线程中进行绘制，因此 Qt 提示说它不能保证操作(例如，在您的情况下，它显然不会产生问题，但 Qt 不保证这种情况总是发生)。来自其他线程的 GUI 更新必须是间接的，可以通过信号、QEvent、QMetaObject::invokeMethod 等。在本例中我将使用信号:

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
import thread_for_audio_record
import time


class FW(object):
    def f_w(self, window):
        self.window = window
        self.window.setObjectName("Test")
        self.window.resize(1054, 700)
        self.window.setStyleSheet("background-color: rgb(180, 180, 180);")
        self.central_widget = QtWidgets.QWidget(self.window)
        self.central_widget.setObjectName("centralwidget")
        self.horizontal_layout = QtWidgets.QHBoxLayout(self.central_widget)
        self.horizontal_layout.setObjectName("horizontalLayout")
        spacer_item = QtWidgets.QSpacerItem(129, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontal_layout.addItem(spacer_item)
        self.vertical_layout = QtWidgets.QVBoxLayout()
        self.vertical_layout.setObjectName("verticalLayout")
        spacer_item_1 = QtWidgets.QSpacerItem(128, 13, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.vertical_layout.addItem(spacer_item_1)
        self.label_utterance = QtWidgets.QLabel(self.central_widget)
        font = QtGui.QFont()
        font.setPointSize(15)
        font.setBold(True)
        font.setBold(True)
        font.setWeight(75)
        self.label_utterance.setFont(font)
        self.label_utterance.setAlignment(QtCore.Qt.AlignCenter)
        self.label_utterance.setObjectName("label_utterance")
        self.vertical_layout.addWidget(self.label_utterance)
        self.text_edit_utterance = QtWidgets.QTextEdit(self.central_widget)
        self.text_edit_utterance.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.text_edit_utterance.setObjectName("text_edit_utterance")
        self.text_edit_utterance.setReadOnly(True)
        self.text_edit_utterance.setFont(font)
        self.vertical_layout.addWidget(self.text_edit_utterance)
        self.line_edit_message_for_user = QtWidgets.QLineEdit(self.central_widget)
        self.line_edit_message_for_user.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.line_edit_message_for_user.setObjectName("lineEdit")
        self.progressBar = QtWidgets.QProgressBar(self.central_widget)
        self.progressBar.setProperty("value", 0)
        self.progressBar.setObjectName("progressBar")
        self.vertical_layout.addWidget(self.progressBar)
        self.vertical_layout.addWidget(self.line_edit_message_for_user)
        self.push_button_start_recording = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_start_recording.setFont(font)
        self.push_button_start_recording.setStyleSheet("background-color: rgb(85, 170, 0);")
        self.push_button_start_recording.setObjectName("pushButton_start_ recording")
        self.vertical_layout.addWidget(self.push_button_start_recording)
        self.push_button_end_recording = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_end_recording.setFont(font)
        self.push_button_end_recording.setStyleSheet("background-color: rgb(182, 0, 0);")
        self.push_button_end_recording.setObjectName("pushButton_end_recording")
        self.vertical_layout.addWidget(self.push_button_end_recording)
        self.label_status = QtWidgets.QLabel(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.label_status.setFont(font)
        self.label_status.setObjectName("label_status")
        self.vertical_layout.addWidget(self.label_status)
        self.text_edit_status = QtWidgets.QTextEdit(self.central_widget)
        self.text_edit_status.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.text_edit_status.setObjectName("textEdit_status")
        self.text_edit_status.setReadOnly(True)
        self.vertical_layout.addWidget(self.text_edit_status)
        self.push_button_record_again = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_record_again.setFont(font)
        self.push_button_record_again.setStyleSheet("background-color: rgb(255, 255, 127);")
        self.push_button_record_again.setObjectName("pushButton_record_again")
        self.vertical_layout.addWidget(self.push_button_record_again)
        self.push_button_next_utterance = QtWidgets.QPushButton(self.central_widget)
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.push_button_next_utterance.setFont(font)
        self.push_button_next_utterance.setStyleSheet("background-color: rgb(85, 170, 0);")
        self.push_button_next_utterance.setObjectName("pushButton_next_utterance")
        self.vertical_layout.addWidget(self.push_button_next_utterance)
        spacer_item_2 = QtWidgets.QSpacerItem(128, 13, QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        self.vertical_layout.addItem(spacer_item_2)
        self.horizontal_layout.addLayout(self.vertical_layout)
        spacer_item_3 = QtWidgets.QSpacerItem(128, 20, QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Minimum)
        self.horizontal_layout.addItem(spacer_item_3)
        self.window.setCentralWidget(self.central_widget)
        self.menubar = QtWidgets.QMenuBar(self.window)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 1054, 21))
        self.menubar.setObjectName("menubar")
        self.window.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(self.window)
        self.statusbar.setObjectName("statusbar")
        self.window.setStatusBar(self.statusbar)
        self.retranslate_ui(self.window)
        QtCore.QMetaObject.connectSlotsByName(self.window)

    def retranslate_ui(self, window):

        _translate = QtCore.QCoreApplication.translate
        window.setWindowTitle(_translate("Utterance Recording", "Altran Audio Manager"))
        self.label_utterance.setText(_translate("Utterance Recording", "Test"))
        self.line_edit_message_for_user.setText(_translate("Utterance Recording", "Test."))
        self.text_edit_utterance.setText(_translate("utterance_parsing", ('Test')))
        self.push_button_start_recording.setText(_translate("Utterance Recording", "Start Recording"))
        self.push_button_end_recording.setText(_translate("Utterance Recording", "End Recording"))
        self.label_status.setText(_translate("Utterance Recording", "Test"))
        self.push_button_record_again.setText(_translate("Utterance Recording", "Test"))
        self.push_button_next_utterance.setText(_translate("Utterance Recording", "Test"))


class MainWindow(QtWidgets.QMainWindow, FW):
    progressChanged = QtCore.pyqtSignal(int)

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.threadpool = QtCore.QThreadPool()
        self.f_w(self)
        self.push_button_start_recording.clicked.connect(self.start_button_func)
        self.progressChanged.connect(self.progressBar.setValue)

    def inside_thread(self):
        percentage = 0
        while percentage < 120:
            percentage = percentage + 20
            time.sleep(0.2)
            self.progressChanged.emit(percentage)

    def start_button_func(self):
        self.worker = thread_for_audio_record.Worker(self.inside_thread)
        self.threadpool.start(self.worker)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

关于python - QObject::setParent:无法设置父级，新父级位于Python中的不同线程中，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55257343/

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