如何使用多核处理 setText 动态更改 pyqt QLabel 的内容

Question

I'm trying to create a program to get the results from a measurement device and display them on the UI using multicoreprocessing. 2 days of hard work, I'm trying to revise the code to see if I can display the results, but I can't figure it out, so I asked this question. My question is I want to change the content of PySide's QLabel dynamically, but because of multicoreprocessing, I can't change it dynamically. I searched the net, but there is no detailed information on how to do this, so I asked this question.

Error Description

Process Process-2:
Traceback (most recent call last):
File "C:\Users\user\AppData\Local\Programs\Python\Python37\lib\multiprocessing\process.py", line 297, in _bootstrap
self.run()
File "C:\Users\user\AppData\Local\Programs\Python\Python37\lib\multiprocessing\process.py", line 99, in run
self._target(*self._args, **self._kwargs)
File "D:\Hiroshi\Program\Mitutoyo\test005.py", line 98, in lcd
self.ct_label.setText(q.get())
AttributeError: 'Main' object has no attribute 'ct_label

from multiprocessing import Queue, Process, freeze_support
import sys
from PySide6.QtWidgets import *
from PySide6 import QtWidgets
from PySide6.QtWidgets import QApplication, QLabel
from PySide2.QtCore import QTimer, QObject, Signal, Slot, QThread, QTimer
import time
import datetime
import csv
from playsound import playsound
from mitutoyo import mitutoyo
import signal

from multiprocessing import pool
import dill
import pickle

threshold = 0.030

sound01 = "D:\\DEFAULT.ACER\\Programing\\PycharmProjects\\Mitutoyo\\dial-guage\\sound\\0.010.wav"

class Main(QtWidgets.QLabel):

    def __setstate__(self, state):
        """非 Pickle 化されるとき呼ばれる"""
        # オブジェクトの持つ属性を復元する
        self.__dict__.update(state)

    def __getstate__(self):
        """Pickle 化されるとき呼ばれる"""
        # オブジェクトの持つ属性をコピーする
        self.__dict__.copy()

    def __init__(self, parent=None):
        super().__init__(parent)
        self.initUI()
        #self.setText("sdsdsdsdsdsdsds")

    def initUI(self):
        # プログラムスタートボタン
        self.btn01 = self.auto_button = QPushButton("開始", self)
        self.btn01.clicked.connect(self.start)
        self.btn01.move(0, 0)
        self.btn01.resize(200, 50)

        # プログラムを閉じるボタン
        self.btn01 = self.auto_button =  QPushButton("停止", self)
        self.btn01.clicked.connect(self.exit_main)
        self.btn01.move(0, 50)
        self.btn01.resize(200, 50)

        # CTの表示
        self.ct_label = QLabel("")
        #self.ct_label.move(300, 0)
        #self.ct_label.resize(400, 100)
        #self.style = ("font-size: 128px;")
        #self.ct_label.setStyleSheet(self.style)

        # Status Barの表示
        self.status_bar01 = QLabel("", self)
        self.status_bar01.move(0, 110)
        self.status_bar01.resize(2000,2000)


    def start(self):
        main = Main()
        q = Queue()
        p0 = Process(target = main.loop, args=(q,))
        p1 = Process(target = main.lcd, args=(q,))
        p2 = Process(target = main.alarm, args=(q,))

        p0.start()
        p1.start()
        p2.start()

    # whileループでミツトヨからのデータを取得し、LCDの表示と色の変更
    def loop(self, q):
        while True:
            self.value = mitutoyo()
            q.put(self.value)


    # exitが押された場合プログラム強制終了
    def exit_main(self, q):
        sys.exit()


    # LCD表示
    def lcd(self, q,):
        while True:
            self.ct_label.setText(q.get())

            #print(self.value)

            #self.styleA = "QWidget{background-color:%s}" % ("green" if float(self.value) < threshold else "brown")
            #self.status_bar01.setStyleSheet(self.styleA)

    # 警告音 ok
    def alarm(self, q):
        while True:
            if float(q.get()) > 0.010:
                print("sdsdsdsdwsdwdw")
                #playsound(sound01)

if __name__ == '__main__':

    freeze_support()

    app = QApplication(sys.argv) #不明。実行には必ず必要
    main_window = Main() #class Ppf()を表示
    main_window.setWindowTitle("歪 アラーム Ver.0.0.1") #windowのtitle
    main_window.setFixedSize(600, 600) #ソフトのサイズとサイズの固定
    #main_window.showMaximized() #ソフトのサイズとサイズの固定
    main_window.show()

    app.exec_() #不明。実行には必ず必要

Answer 1

What about using the event-mechanism of (Py)Qt.

As any Widget subclass in Qt, the QLabel has event-handlers that can be implemented .

When one or both of your concurrent processes is emitting a QEvent , they can be interpreted on the QLabel inside one of these, like event(QEvent e) .

See also:

• Binding event handlers in PyQT
• An introduction to PyQt5 Signals, Slots and Events
• PyQt events | Learn Python PyQt