python - 如何在数据更新时自动刷新pyqt5表

Question

我想在更新完成后在我的应用程序中添加一项功能，然后 pyqt5 表中的数据应使用搜索结果中的新数据自动刷新。但是当我点击按钮时，什么也没有发生。

# -*- coding: utf-8 -*-

from PyQt5 import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
import sys
import logging
import logging.config
import time



class Ui_Control_system(object):



    def setupUi(self, Control_system):

        Control_system.setObjectName("Control_system")
        Control_system.resize(1004, 722)
        Control_system.setFixedSize(1004, 722)

        Control_system.setWindowIcon(QIcon('images/icon.png'))
        Control_system.setStyleSheet("QMainWindow{border-image:url(images/background.jpg)}")

        self.centralwidget = QtWidgets.QWidget(Control_system)
        self.centralwidget.setObjectName("centralwidget")

        #表格显示
        self.tableWidget = QtWidgets.QTableWidget(self.centralwidget)
        self.tableWidget.setGeometry(QtCore.QRect(130, 170, 752, 245))
        self.tableWidget.setRowCount(8)
        self.tableWidget.setColumnCount(6)
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.horizontalHeader().setVisible(False)
        self.tableWidget.horizontalHeader().setCascadingSectionResizes(False)
        self.tableWidget.horizontalHeader().setDefaultSectionSize(125)
        self.tableWidget.horizontalHeader().setHighlightSections(True)
        self.tableWidget.horizontalHeader().setSortIndicatorShown(False)
        self.tableWidget.verticalHeader().setVisible(False)
        Control_system.setCentralWidget(self.centralwidget)
        self.tableWidget.setAutoFillBackground(True)

        self.tableWidget.setItem(0,0,QTableWidgetItem("机器编号"))
        self.tableWidget.setItem(0,1,QTableWidgetItem("烟雾值"))
        self.tableWidget.setItem(0,2,QTableWidgetItem("火焰值"))
        self.tableWidget.setItem(0,3, QTableWidgetItem("温度值"))
        self.tableWidget.setItem(0,4, QTableWidgetItem("电流值"))
        self.tableWidget.setItem(0,5, QTableWidgetItem("电压值"))
        font = QtGui.QFont()
        font.setPointSize(15)
        font.setBold(True)
        self.tableWidget.item(0,0).setFont(font)
        self.tableWidget.item(0,1).setFont(font)
        self.tableWidget.item(0,2).setFont(font)
        self.tableWidget.item(0,3).setFont(font)
        self.tableWidget.item(0,4).setFont(font)
        self.tableWidget.item(0,5).setFont(font)



        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(360, 70, 300, 50))
        self.label.setObjectName("label")
        self.label.setAutoFillBackground(True)
        self.label.setAlignment(Qt.AlignCenter)   
        self.label.setStyleSheet("border-image:url(images/title.png)")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(730, 480, 121, 41))
        self.pushButton.setObjectName("pushButton")
        self.pushButton.clicked.connect(self.slotStart)


        Control_system.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(Control_system)
        self.statusbar.setObjectName("statusbar")
        Control_system.setStatusBar(self.statusbar)

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


    def retranslateUi(self, Control_system):
        _translate = QtCore.QCoreApplication.translate
        Control_system.setWindowTitle(_translate("Control_system", "实时监控系统"))
        self.pushButton.setText(_translate("Control_system", "开始运行"))


    def slotStart(self):
        #开始按钮不可点击，线程开始
        self.pushButton.setEnabled(False)
        self.update_data_thread = UpdateData()
        self.update_data_thread.update_data.connect(self.set_btn)
        self.update_data_thread.start()

    def set_btn(self):
        self.pushButton.setEnabled(True)



class UpdateData(QtCore.QThread):#使用qt自己本身的线程

    update_data=QtCore.pyqtSignal()#因为这个信号槽要继承于Qobject，不然会发生没有emit，connect函数的报错，括号里面填写的是发射的数据类型
    #print(".............")

    def __init__(self):
        super().__init__()

    def run(self):
        cnt = 0
        while True:
            cnt += 1
            self.tableWidget.setItem(2,2,QTableWidgetItem(cnt))
            self.update_data.emit()  # 发射信号
            time.sleep(1)



if __name__ == '__main__':

    if not QtWidgets.QApplication.instance():
        app = QtWidgets.QApplication(sys.argv)
    else:
        app = QtWidgets.QApplication.instance() 
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_Control_system() 
    ui.setupUi(MainWindow) # 将ui实例绘制到窗口实例上​  


    desktop = QtWidgets.QApplication.desktop()
    x = (desktop.width() - MainWindow.width()) // 2
    y = (desktop.height() - MainWindow.height()) // 2
    MainWindow.move(x,y)
    MainWindow.show() 
    sys.exit(app.exec())#exec_()方法的作用是“进入程序的主循环直到exit()被调

Answer 1

您不能也不应该直接从另一个线程修改 GUI，在您的情况下 QTableWidget 和 QTableWidgetItem 是 GUI 的一部分，因此代码: self.tableWidget.setItem(2, 2, QTableWidgetItem(cnt)) 不正确。应该做的是通过信号、QEvents等线程安全的元素将信息发送到主线程。

另一方面，PyQt 建议不要修改它生成的类，而是创建一个小部件并将生成的类用作接口(interface)⁽¹⁾。

考虑到上述情况，解决方案是:

import sys
import time

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_Control_system(object):
    def setupUi(self, Control_system):

        Control_system.setObjectName("Control_system")
        Control_system.resize(1004, 722)
        Control_system.setFixedSize(1004, 722)

        Control_system.setWindowIcon(QtGui.QIcon("images/icon.png"))
        Control_system.setStyleSheet(
            "QMainWindow{border-image:url(images/background.jpg)}"
        )

        self.centralwidget = QtWidgets.QWidget(Control_system)
        self.centralwidget.setObjectName("centralwidget")

        # 表格显示
        self.tableWidget = QtWidgets.QTableWidget(self.centralwidget)
        self.tableWidget.setGeometry(QtCore.QRect(130, 170, 752, 245))
        self.tableWidget.setRowCount(8)
        self.tableWidget.setColumnCount(6)
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.horizontalHeader().setVisible(False)
        self.tableWidget.horizontalHeader().setCascadingSectionResizes(False)
        self.tableWidget.horizontalHeader().setDefaultSectionSize(125)
        self.tableWidget.horizontalHeader().setHighlightSections(True)
        self.tableWidget.horizontalHeader().setSortIndicatorShown(False)
        self.tableWidget.verticalHeader().setVisible(False)
        Control_system.setCentralWidget(self.centralwidget)
        self.tableWidget.setAutoFillBackground(True)

        self.tableWidget.setItem(0, 0, QtWidgets.QTableWidgetItem("机器编号"))
        self.tableWidget.setItem(0, 1, QtWidgets.QTableWidgetItem("烟雾值"))
        self.tableWidget.setItem(0, 2, QtWidgets.QTableWidgetItem("火焰值"))
        self.tableWidget.setItem(0, 3, QtWidgets.QTableWidgetItem("温度值"))
        self.tableWidget.setItem(0, 4, QtWidgets.QTableWidgetItem("电流值"))
        self.tableWidget.setItem(0, 5, QtWidgets.QTableWidgetItem("电压值"))
        font = QtGui.QFont()
        font.setPointSize(15)
        font.setBold(True)
        self.tableWidget.item(0, 0).setFont(font)
        self.tableWidget.item(0, 1).setFont(font)
        self.tableWidget.item(0, 2).setFont(font)
        self.tableWidget.item(0, 3).setFont(font)
        self.tableWidget.item(0, 4).setFont(font)
        self.tableWidget.item(0, 5).setFont(font)

        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(360, 70, 300, 50))
        self.label.setObjectName("label")
        self.label.setAutoFillBackground(True)
        self.label.setAlignment(QtCore.Qt.AlignCenter)
        self.label.setStyleSheet("border-image:url(images/title.png)")

        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(730, 480, 121, 41))
        self.pushButton.setObjectName("pushButton")

        Control_system.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(Control_system)
        self.statusbar.setObjectName("statusbar")
        Control_system.setStatusBar(self.statusbar)

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

    def retranslateUi(self, Control_system):
        _translate = QtCore.QCoreApplication.translate
        Control_system.setWindowTitle(_translate("Control_system", "实时监控系统"))
        self.pushButton.setText(_translate("Control_system", "开始运行"))


class Control_system(QtWidgets.QMainWindow, Ui_Control_system):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)
        self.pushButton.clicked.connect(self.slotStart)

    @QtCore.pyqtSlot()
    def slotStart(self):
        self.pushButton.setEnabled(False)
        self.update_data_thread = UpdateData(self)
        self.update_data_thread.dataChanged.connect(self.onDataChanged)
        self.update_data_thread.start()

    @QtCore.pyqtSlot(int, int, str)
    def onDataChanged(self, row, column, text):
        it = self.tableWidget.item(row, column)
        if it is None:
            it = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(row, column, it)
        it.setText(text)


class UpdateData(QtCore.QThread):
    dataChanged = QtCore.pyqtSignal(int, int, str)

    def run(self):
        cnt = 0
        while True:
            cnt += 1
            self.dataChanged.emit(2, 2, str(cnt))
            time.sleep(1)


if __name__ == "__main__":
    app = QtWidgets.QApplication.instance()
    if app is None:
        app = QtWidgets.QApplication(sys.argv)
    w = Control_system()
    w.show()
    sys.exit(app.exec_())

更新:

class Control_system(QtWidgets.QMainWindow, Ui_Control_system):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)
        self.pushButton.clicked.connect(self.slotStart)
        self.pushButton_2.clicked.connect(self.slotStop)

    @QtCore.pyqtSlot()
    def slotStart(self):
        # ...

    @QtCore.pyqtSlot(int, int, str)
    def onDataChanged(self, row, column, text):
        it = self.tableWidget.item(row, column)
        if it is None:
            it = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(row, column, it)
        it.setText(text)

    @QtCore.pyqtSlot()
    def slotStop(self):
        self.update_data_thread.requestInterruption()
        self.update_data_thread.quit()
        self.update_data_thread.wait()
        self.pushButton.setEnabled(True)

class UpdateData(QtCore.QThread):
    dataChanged = QtCore.pyqtSignal(int, int, str)

    def run(self):
        cnt = 0
        while not self.isInterruptionRequested(): # <---
            cnt += 1
            self.dataChanged.emit(2, 2, str(cnt))
            time.sleep(1)

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^{(1) Using the Generated Code}