引言

有些时候，我们需要线程进行UI操作，因为主线程在执行耗时操作的时候，UI会卡死，导致程序进入假死状态，这时候应当考虑线程操作UI，但是非UI线程操作UI是不被允许的，这时候就需要定义一个信号量，通知主线程修改UI。

定义启动类

结构说明

bootstrap.py 启动器
main.ui ui文件
main.py ui转换成的py文件

启动器类

一般情况下，我们使用qtdesigner进行UI设计，通过PyUIC转成py源码，但是如果我们UI并不能一次性设计好，并且需要绑定槽和一系列操作，就不能修改UIC后的文件，因为一旦重新ui生成py文件，那就会把之前的代码清除掉，所以在这里我们需要再定义一个类，暂且叫作bootstrap.py

class my_window(main.UI_MainWindow): # main.UI_MainWindow 就是main.py中的Ui_MainWindow类
    def __init__(self):
         super(window,self)


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = Dialog()
    ui = window()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

这时候，我们继承了main.py，就可以随心所欲的健壮我们的代码了。

线程操作

不使用线程操作

main.py

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

# Form implementation generated from reading ui file 'main2.ui'
#
# Created by: PyQt5 UI code generator 5.15.9
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again.  Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(336, 310)
        MainWindow.setWindowTitle("")
        MainWindow.setStyleSheet("color:white")
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName("gridLayout")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setObjectName("pushButton")
        self.gridLayout.addWidget(self.pushButton, 1, 0, 1, 1)
        self.lcdNumber = QtWidgets.QLCDNumber(self.centralwidget)
        self.lcdNumber.setSmallDecimalPoint(False)
        self.lcdNumber.setDigitCount(10)
        self.lcdNumber.setProperty("intValue", 2)
        self.lcdNumber.setObjectName("lcdNumber")
        self.gridLayout.addWidget(self.lcdNumber, 0, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)

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

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

bootstrap.py

import sys
import time
from PyQt5 import QtWidgets
from PyQt5.QtCore import QTimer
import main


class my_window(main.Ui_MainWindow):

    def __init__(self):
        super(my_window, self)

    def click(self):
        time.sleep(1)
        self.lcdNumber.display(self.lcdNumber.intValue() + 1)

    def interval(self):
        self.lcdNumber.display(self.lcdNumber.intValue() + 1)

    def initialize(self):
        self.q_timer = QTimer() # 一定要用self，不然不生效，这也就是为什么用继承的原因
        self.q_timer.timeout.connect(self.interval)
        self.q_timer.start(100)
        self.pushButton.clicked.connect(self.click)


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

当点击按钮的时候，UI会卡死1秒钟

线程的错误用法

import sys
import threading
import time
from PyQt5 import QtWidgets
from PyQt5.QtCore import QTimer

import main2


class my_window(main2.Ui_MainWindow):

    def __init__(self):
        super(my_window, self)

    def click(self):
        print("Click")
        time.sleep(1)
        self.lcdNumber.display(self.lcdNumber.intValue() + 1000)
        print("Done")

    def interval(self):
        self.lcdNumber.display(self.lcdNumber.intValue() + 1)

    def mythread(self):
        threading.Thread(target=self.click).start()

    def initialize(self):
        self.q_timer = QTimer()
        self.q_timer.timeout.connect(self.interval)
        self.q_timer.start(100)
        self.pushButton.clicked.connect(self.mythread)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = my_window()
    ui.setupUi(MainWindow)

    ui.initialize()
    MainWindow.show()
    sys.exit(app.exec_())

这种用法可能会导致Process finished with exit code -1073740791 (0xC0000409)，很奇怪，之前的代码这样做出现过这个报错，但是写Demo的时候，居然可以正常运行了。

正确用法

import sys
import threading
import time
from PyQt5 import QtWidgets
from PyQt5.QtCore import QTimer, QThread, pyqtSignal

import main2


class my_thread(QThread):
    update_ui_signal = pyqtSignal(int)

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

    def run(self):
        for i in range(1, 1000):
            self.update_ui_signal.emit(1)


class my_window(main2.Ui_MainWindow):

    def __init__(self):
        super(my_window, self)

    def update_ui_function(self, n):
        self.lcdNumber.display(n + self.lcdNumber.intValue())

    def click(self):
        self.thread = my_thread()
        self.thread.update_ui_signal.connect(self.update_ui_function)
        self.thread.start()

    def interval(self):
        self.lcdNumber.display(self.lcdNumber.intValue() + 1)

    def initialize(self):
        self.q_timer = QTimer()
        self.q_timer.timeout.connect(self.interval)
        self.q_timer.start(100)
        self.pushButton.clicked.connect(self.click)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = my_window()
    ui.setupUi(MainWindow)

    ui.initialize()
    MainWindow.show()
    sys.exit(app.exec_())