使用PyQt5轻松实现多线程，用于更新QTextBrowser内容

Question

I have found stuff online suggesting that PyQt5 widgets are not thread safe. And other Stackoverflow answers suggest creating a class that only fits their problem. I tried using _thread module in Python 3 which works for everything except PyQt.

app = QApplication([])
Ui_MainWindow, QtBaseClass = uic.loadUiType("UI/action_tab.ui") #specify the location of your .ui file


class MyApp(QMainWindow):
    def __init__(self):
        super(MyApp, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.threadPool = QThreadPool()
        self.ui.queryBox.returnPressed.connect(self.load_response)

    def start_loader(self):
        self.loading_animate = QMovie('IMAGES/GIFS/load_resp.gif')
        self.loading_animate.setScaledSize(QSize(400, 300))
        self.ui.loader.setMovie(self.loading_animate)
        self.loading_animate.setSpeed(200)
        self.ui.loader.show()
        self.loading_animate.start()

    def stop_loader(self):
        self.ui.loader.hide()
        self.loading_animate.stop()

    def get_response(self):
        plain_text, speech = get_Wresponse(self.ui.queryBox.displayText())
        self.stop_loader()
        self.ui.textDisplay.setText(plain_text)
        if speech == '':
            say("Here you GO!")
        else:
            say(speech)

    def load_response(self):
        self.start_loader()
        _thread.start_new_thread(self.get_response, ())
        #self.get_response()


if __name__ == '__main__':
    window = MyApp()
    window.setWindowFlags(Qt.FramelessWindowHint)
    window.show()
    sys.exit(app.exec())

Error in above code follows,

QObject: Cannot create children for a parent that is in a different thread. (Parent is QTextDocument(0x19fe090b8c0), parent's thread is QThread(0x19fde197fb0), current thread is QThread(0x19fe3a0a5f0)

Do you think you can save me? Please Do ! Thanks in Advance!!

Answer 1

You do not have to update the GUI from an external thread. There are several options like signals, QMetaObject::invokeMethod(...) , QEvent and QTimer::singleShot(0, ...) with pyqtSlot.

Using the last method the solution is as follows:

from functools import partial
from PyQt5.QtCore import pyqtSlot

class MyApp(QMainWindow):
    # ...

    @pyqtSlot()
    def stop_loader(self):
        self.ui.loader.hide()
        self.loading_animate.stop()

    def get_response(self, text):
        plain_text, speech = get_Wresponse(text)
        QtCore.QTimer.singleShot(0, self.stop_loader)
        wrapper = partial(self.ui.textDisplay.setText, plain_text)
        QtCore.QTimer.singleShot(0, wrapper)
        if speech == '':
            say("Here you GO!")
        else:
            say(speech)

    def load_response(self):
        self.start_loader()
        text = self.ui.queryBox.displayText()
        _thread.start_new_thread(self.get_response, (text,))