为什么我的 QThread 类大大减慢了 PyQT5 应用程序的速度？

Question

我正面临 Threads 的问题。我正在用进度条显示当前的 CPU 使用情况，它似乎运行良好，但整个窗口的性能很糟糕。如果没有滞后行为，甚至无法单击按钮。有什么简单的解决办法吗？

这是我的主要代码

from PyQt5 import QtCore, QtGui,  QtWidgets
from PyQt5.QtCore import QThread, pyqtSignal


import progressBarUI
import sys
import sysnfo


class MainWindow(QtWidgets.QMainWindow, progressBarUI.Ui_MainWindow):
    def __init__(self, parent = None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)
        self.threadclass = ThreadClass()
        self.threadclass.start()
        self.threadclass.signal.connect(self.updateProgressBar)

    def updateProgressBar(self):
        current_percentage = sysnfo.getCpuPercentage()
        self.progressBar.setValue(current_percentage)


class ThreadClass(QThread):
    signal = pyqtSignal(int)

    def __init__(self, parent=None):
        super(ThreadClass, self).__init__(parent)

    def run(self):
        while True:
            current_percentage = sysnfo.getCpuPercentage()
            self.signal.emit(current_percentage)


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

这里是 sysnfo 模块：

import psutil as ps

def getCpuPercentage():
    return ps.cpu_percent(interval=1)

和UI文件（转换为.py文件）：

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(787, 203)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")

        self.progressBar = QtWidgets.QProgressBar(self.centralwidget)
        self.progressBar.setGeometry(QtCore.QRect(370, 20, 381, 111))
        self.progressBar.setProperty("value", 0)
        self.progressBar.setObjectName("progressBar")


        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(20, 50, 151, 41))
        self.pushButton.setObjectName("pushButton")

        MainWindow.setCentralWidget(self.centralwidget)

        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 787, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)

        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Click me"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answer 1

当您使用“interval”参数时，您表示它会测量该时间段内的信息并计算导致该函数执行花费“interval”秒的平均值，正确的做法是在另一个线程中执行它，但是您错误地在阻塞它的主线程中的 updateProgressBar 方法中也执行它，而是使用向您发送信号的信息：

@QtCore.pyqtSlot(int)
def updateProgressBar(self, percentage):
    self.progressBar.setValue(percentage)