保持 PyQt5 GUI 运行，同时等待另一个线程完成

Question

I am trying keep a PyQt5 GUI running after a starting a function from a different file in a different thread, which works fine, and then wait for that thread to finsish to update some text on the GUI, which does not work fine.

File 1 (main.py):

from PyQt5.QtWidgets import  QMainWindow, QApplication,  QPushButton, QTextEdit
from PyQt5.QtGui import QFont
import sys
from threading import Thread

class Window(QMainWindow):
    def __init__(self):
        super().__init__()
  
        self.setWindowTitle("test")
        self.initWidgets()
        self.initWindow()

    def initWindow(self):
        self.setGeometry(0, 0, 300, 300)
        self.show()
    
    def initWidgets(self):
        self.goButton = QPushButton("go", self)
        self.goButton.resize(100, 50)
        self.goButton.move(30, 30)
        self.goButton.setFont(QFont("Calibri", 11))
        self.goButton.clicked.connect(self.goButtonClicked)

        self.textBox = QTextEdit(self)
        self.textBox.resize(200, 40)
        self.textBox.move(30, 100)

        self.outBox = QTextEdit(self)
        self.outBox.resize(200, 40)
        self.outBox.move(30, 150)

       
    def goButtonClicked(self):
        self.var = self.textBox.toPlainText()
        from filewithfunc import testfunc
        self.thread1 = Thread(target=testfunc, args=(self.var,), daemon=False)
        self.thread1.start()
        self.thread2 = Thread(target=self.updateText)
        self.thread2.start()

    def updateText(self):
        self.thread1.join()
        from filewithfunc import capVar
        self.outBox.setText(capVar)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Window()
    sys.exit(app.exec())

File 2 (filewithfunc.py):

from time import sleep

def testfunc(var):
    sleep(5)
    global capVar
    capVar = var.capitalize()
   

Basically after pushing the button, the testfunc() function is called with variable from the textbox, and is then later displayed in the other textbox once the function finishes. I create a different thread for the both the testfunc() and updateText() function in hopes that it will keep the GUI from freezing, but I get this error:

QObject: Cannot create children for a parent that is in a different thread.
(Parent is QTextDocument(0x1cb0c9aeff0), parent's thread is QThread(0x1cb0ca13cd0), current thread is QThread(0x1cb109b8310)

What can I do to remedy this. I read about using QThread, but I feel like that is slightly overkill and could just be done with threading, I might be wrong though.

Answer 1

Figured it out on my own, looks like QThread was definitely the way to go, quite easy to implement. Final code looks like this.

from PyQt5.QtWidgets import  QMainWindow, QApplication,  QPushButton, QTextEdit
from PyQt5.QtCore import QThread
from PyQt5.QtGui import QFont

import sys
from threading import Thread

class Window(QMainWindow):
    def __init__(self):

        Window.var = "t"

        super().__init__()
  
        self.setWindowTitle("test")
        self.initWidgets()
        self.initWindow()

    def initWindow(self):
        self.setGeometry(0, 0, 300, 300)
        self.show()
    
    def initWidgets(self):
        self.goButton = QPushButton("go", self)
        self.goButton.resize(100, 50)
        self.goButton.move(30, 30)
        self.goButton.setFont(QFont("Calibri", 11))
        self.goButton.clicked.connect(self.goButtonClicked)

        self.textBox = QTextEdit(self)
        self.textBox.resize(200, 40)
        self.textBox.move(30, 100)

        self.outBox = QTextEdit(self)
        self.outBox.resize(200, 40)
        self.outBox.move(30, 150)

       
    def goButtonClicked(self):
        Window.var = self.textBox.toPlainText()
        self.worker = workerThread()
        self.worker.start()
        self.worker.finished.connect(self.updateText)
        

    def updateText(self):
        from filewithfunc import capVar
        self.outBox.setText(capVar)


class workerThread(QThread):
    def run(self):
        from filewithfunc import testfunc
        self.funcThread = Thread(target=testfunc, args=(Window.var,), daemon=True)
        self.funcThread.start()
        print("sat")
        self.funcThread.join()


app = QApplication(sys.argv)
window = Window()
sys.exit(app.exec())

Basically when goButton is clicked, a worked thread is started which imports and calls the function from the other file, then waits for it to finish before updating the text on the screen.