在Dash回调中显示PyQt5元素

逻辑是在辅助线程中运行Dash并通过如下所示的信号将通知发送到GUI（此答案基于我的其他答案）：

import functools
import os
import threading

from PyQt5 import QtCore, QtWidgets

import dash
import dash_html_components as html
from dash.dependencies import Input, Output


class MainWindow(QtWidgets.QMainWindow):
    closed = QtCore.pyqtSignal()

    def closeEvent(self, event):
        self.closed.emit()
        super().closeEvent(event)


class Manager(QtCore.QObject):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._view = None

    @property
    def view(self):
        return self._view

    def init_gui(self):
        self._view = MainWindow()

    @QtCore.pyqtSlot()
    def show_popup(self):
        if self.view is not None:
            self.view.show()


qt_manager = Manager()

app = dash.Dash()

app.layout = html.Div(
    children=[
        html.H1(children="Hello Dash"),
        html.Button("show pop up", id="button"),
        html.H2(children="", id="result"),
    ]
)


@app.callback(
    Output(component_id="result", component_property="children"),
    [Input(component_id="button", component_property="n_clicks")],
)
def popUp(n_clicks):
    if not n_clicks:
        raise dash.exceptions.PreventUpdate

    loop = QtCore.QEventLoop()
    qt_manager.view.closed.connect(loop.quit)
    QtCore.QMetaObject.invokeMethod(
        qt_manager, "show_popup", QtCore.Qt.QueuedConnection
    )
    loop.exec_()

    return "You saw a pop-up"


def main():
    qt_app = QtWidgets.QApplication.instance()
    if qt_app is None:
        qt_app = QtWidgets.QApplication([os.getcwd()])
    qt_app.setQuitOnLastWindowClosed(False)
    qt_manager.init_gui()
    threading.Thread(
        target=app.run_server, kwargs=dict(debug=False), daemon=True,
    ).start()

    return qt_app.exec_()


if __name__ == "__main__":
    main()

回答来源：stackoverflow