Python程序在函数中对PyQt5窗口cant setwindow.title进行子类化

Question

我有一个示例Python程序，它将PyQt5窗口划分为子类。我在自学，还有一些新的PyQt5和python课程

程序做了我想做的事情，但我遇到了一个我不知道如何修复的错误。为了按原样启动这个程序，我正在学习如何运行Threads。我导入了PyQt5窗口并对其进行了子分类。在子类的__init__部分，我可以设置窗口标题，它工作正常

如果我将语句移动到函数"def initUI(self):"，我无法设置窗口标题，请注意，我尝试了不同版本的语句，但没有任何效果。这是def的第一行，我已将其注释掉

我的问题是：

1. 此属性可在def中设置

2. 如果需要，语句的正确格式是什么

---

from PyQt5.QtCore import pyqtSlot, pyqtSignal
from PyQt5 import QtCore, QtGui, QtWidgets
from Threads import Ui_MainWindow
import sys, time
from time import sleep

class MainWindow_EXEC():
    def __init__(self):             # This section has to be laid out this way 
        app = QtWidgets.QApplication(sys.argv)
        win = QtWidgets.QMainWindow()

        self.ui = Ui_MainWindow()
        self.ui.setupUi(win) 
        self.initUI()               # Inits that need to happen before start up

        win.setWindowTitle("This is the Title!") # Works fine
        win.resize(800,600)
        win.show()  
        sys.exit(app.exec_()) 

    def initUI(self):               # Button assignments
        #self.ui.setWindowTitle("This is the Title!")  # AttributeError: 'Ui_MainWindow' object has no attribute 'setWindowTitle'
        self.ui.btn_Start.clicked.connect(self.start_progressbar)
        self.ui.btn_Stop.clicked.connect(self.stop_progressbar)
        self.ui.btn_Reset.clicked.connect(self.reset_progressbar)
        self.progress_value = 0
        self.stop_progress = False

    def progressbar_counter(self, start_value=0):
        # have to use member: self.run_thread NOT local var: run_thread
        self.run_thread = RunThread(parent=None, counter_start=start_value)
        self.run_thread.start()
        self.run_thread.counter_value.connect(self.get_thread_value)

    def get_thread_value(self, counter):    #This updates the progress bar
        print(counter)
        if not self.stop_progress:
            self.ui.progressBar.setValue(counter)        

    def start_progressbar(self):    # This is the button that starts the progress bar
        self.stop_progress = False  # This is a switch
        self.progress_value = self.ui.progressBar.value()    # Updating the progress bar    
        self.progressbar_counter(self.progress_value)

    def stop_progressbar(self):     # This is a button to stop the progress bar
        self.stop_progress = True
        self.run_thread.stop()

    def reset_progressbar(self):    # This is a button to reset the progress bar
        self.stop_progressbar()
        self.progress_value = 0
        self.stop_progress = False
        self.ui.progressBar.reset()


class RunThread(QtCore.QThread):

    counter_value = QtCore.pyqtSignal(int)                  # define new Signal

    def __init__(self, parent=None, counter_start=0):
        super(RunThread, self).__init__(parent)
        self.counter = counter_start
        self.isRunning = True

    def run(self):
        while self.counter < 100 and self.isRunning == True:
            sleep(0.1)
            self.counter += 1
            print(self.counter)
            self.counter_value.emit(self.counter)     # emit new Signal with value

    def stop(self):
        self.isRunning = False
        print('stopping thread...')
        self.terminate()


if __name__ == "__main__":
    MainWindow_EXEC()

Answer 1

必须区分以下类别的目标：

• QMainWindow是一个具有setWindowTitle方法的小部件
• Ui_MainWindow不是一个小部件，而是一个用于填充小部件的类，因此它没有setWindowTitle方法

解决方案是使win成为类成员，然后使用该对象修改标题：

class MainWindow_EXEC():
    def __init__(self):             # This section has to be laid out this way 
        app = QtWidgets.QApplication(sys.argv)
        self.win = QtWidgets.QMainWindow()

        self.ui = Ui_MainWindow()
        self.ui.setupUi(self.win) 
        self.initUI() 
        self.win.setWindowTitle("This is the Title!")
        self.win.resize(800,600)
        self.win.show()  
        sys.exit(app.exec_()) 

    def initUI(self):               # Button assignments
        self.win.setWindowTitle("This is the Title!")
        self.ui.btn_Start.clicked.connect(self.start_progressbar)
        # ...