使用pyqt5和sqlite的python程序出错，无法为不同线程中的父级创建子级

Question

我使用 pyqt5 和 sqlite db 制作了一个程序。

它随机选择一个数据库的行文本并显示在文本浏览器小部件中，并在我每次按下按钮时复制到剪贴板。

并使用键盘模块，挂钩ctrl + v然后检查标签小部件以重复上一个按钮的功能。

但是当我按下ctrl + v 时，它在 Pycharm 中不起作用并显示此错误消息

Process finished with exit code -1073740791 (0xC0000409)

当我在终端中运行代码时，再次出现此错误消息

QObject: Cannot create children for a parent that is in a different thread.
(Parent is QTextDocument(0x207618a6770), parent's thread is QThread(0x2075f5acef0), current thread is QThread(0x20761d818d0)

我想可能是线程问题。 但我没有使用线程。 这是我的 pyqt5 小部件的 ui 图像和我的源代码。

我怎样才能使这段代码工作？

import sys
from PyQt5.QtWidgets import *
from PyQt5 import uic
import sqlite3
import random
import pyperclip
import keyboard
from time import sleep

form_class = uic.loadUiType("exam.ui")[0]

class WindowClass(QMainWindow, form_class) :
    def __init__(self) :
        super().__init__()
        self.setupUi(self)
        self.pb1.clicked.connect(self.bt1)
        self.pb2.clicked.connect(self.bt2)
        self.pb3.clicked.connect(self.bt3)
        self.pb4.clicked.connect(self.bt4)
        self.pb5.clicked.connect(self.bt5)
        self.con = sqlite3.connect("exam.db")
        self.cursor = self.con.cursor()
        keyboard.add_hotkey("ctrl+v", self.kt)

    def bt1(self):
        self.lb1.clear()
        self.tb.clear()
        self.lb1.setText("a")
        self.cursor.execute("SELECT max(rowid) FROM a")
        maxrow = self.cursor.fetchone()
        r = random.randrange(1, maxrow[0] + 1)
        self.cursor.execute("SELECT * FROM a WHERE rowid =?", (r,))
        t = self.cursor.fetchone()
        self.tb.setPlainText(t[0])
        pyperclip.copy(t[0] + "\n")

    def bt2(self):
        self.lb1.clear()
        self.tb.clear()
        self.lb1.setText("b")
        self.cursor.execute("SELECT max(rowid) FROM b")
        maxrow = self.cursor.fetchone()
        r = random.randrange(1, maxrow[0] + 1)
        self.cursor.execute("SELECT * FROM b WHERE rowid =?", (r,))
        t = self.cursor.fetchone()
        self.tb.setPlainText(t[0])
        pyperclip.copy(t[0] + "\n")

    def bt3(self):
        self.lb1.clear()
        self.tb.clear()
        self.lb1.setText("c")
        self.cursor.execute("SELECT max(rowid) FROM c")
        maxrow = self.cursor.fetchone()
        r = random.randrange(1, maxrow[0] + 1)
        self.cursor.execute("SELECT * FROM c WHERE rowid =?", (r,))
        t = self.cursor.fetchone()
        self.tb.setPlainText(t[0])
        pyperclip.copy(t[0] + "\n")

    def bt4(self):
        self.lb1.clear()
        self.tb.clear()
        self.lb1.setText("d")
        self.cursor.execute("SELECT max(rowid) FROM d")
        maxrow = self.cursor.fetchone()
        r = random.randrange(1, maxrow[0] + 1)
        self.cursor.execute("SELECT * FROM d WHERE rowid =?", (r,))
        t = self.cursor.fetchone()
        self.tb.setPlainText(t[0])
        pyperclip.copy(t[0] + "\n")

    def bt5(self):
        self.lb1.clear()
        self.tb.clear()
        self.lb1.setText("e")
        self.cursor.execute("SELECT max(rowid) FROM e")
        maxrow = self.cursor.fetchone()
        r = random.randrange(1, maxrow[0] + 1)
        self.cursor.execute("SELECT * FROM e WHERE rowid =?", (r,))
        t = self.cursor.fetchone()
        self.tb.setPlainText(t[0])
        pyperclip.copy(t[0] + "\n")

    def kt(self):
        if self.lb1.text() == "a":
            self.bt1()
        elif self.lb1.text == "b":
            self.bt2()
        elif self.lb1.text == "c":
            self.bt3()
        elif self.lb1.text == "d":
            self.bt4()
        elif self.lb1.text == "e":
            self.bt5()
    if __name__ == "__main__" :
        app = QApplication(sys.argv)
        myWindow = WindowClass()
        myWindow.show()
        app.exec_()

db 文件链接ui 文件链接

我只是添加了一个 db 和 ui 文件。

Answer 1

与使用 add_hotkey 注册的快捷方式关联的回调在辅助线程中执行，这意味着您正在从另一个线程修改 GUI，而 Qt 抛出该错误是禁止的。 解决方案是使用从辅助线程发出的信号来调用 kt 方法：

# ...

from PyQt5.QtCore import QObject, pyqtSignal


class KeyboardManager(QObject):
    pasteSignal = pyqtSignal()

    def start(self):
        keyboard.add_hotkey("ctrl+v", self._ctrl_v_callback)

    def _ctrl_v_callback(self):
        self.pasteSignal.emit()


class WindowClass(QMainWindow, form_class):
    def __init__(self):
        super().__init__()
        self.setupUi(self)
        self.pb2.clicked.connect(self.bt2)
        self.pb3.clicked.connect(self.bt3)
        self.pb4.clicked.connect(self.bt4)
        self.pb5.clicked.connect(self.bt5)
        self.con = sqlite3.connect("exam.db")
        self.cursor = self.con.cursor()

        keyboard_manager = KeyboardManager(self) keyboard_manager.pasteSignal.connect(self.kt) keyboard_manager.start()

    def bt1(self):
        # ...

除了前面的错误，你还有一个小错误：如果要获取文本，必须使用带括号的 text() 方法，但是没有正确操作，解决方法如下：

def kt(self):
    if self.lb1.text() == "a":
        self.bt1()
    elif self.lb1.text() == "b":
        self.bt2()
    elif self.lb1.text() == "c":
        self.bt3()
    elif self.lb1.text() == "d":
        self.bt4()
    elif self.lb1.text() == "e":
        self.bt5()