尝试在 pyqt5 gui 应用程序中使用 4x4 键盘

Question

我正在尝试使用 pad4pi 模块和基于 pyqt5 的 GUI 应用程序编写从 4x4 键盘（机械）获取输入的代码。

当我尝试点击按钮时它正常工作但是当我尝试生成某些事件时我收到错误消息：

QObject::startTimer: Timers can only be used with threads started with QThread

class DigitalClock(QWidget,QThread):
    def __init__(self):
        super().__init__()
        SetupKeyboard.keypad.registerKeyPressHandler(self.printKey)
        self.setWindowTitle("OM SAI RAM")
        self.showFullScreen() 
        #self.setCursor(Qt.BlankCursor)
        button = QPushButton("Click", self) 
        button.clicked.connect(self.change)
        button.move(10,10)    
        button.show()

    def change(self):
        self.newpage = Authentication_page()
        self.close()

    def printKey(self, key):
        if key == 'A':
            self.newpage = Authentication_page()
            self.close()

class Authentication_page(QWidget):
    """
    Class to validate authentication.
    """
    def __init__(self):
        super().__init__()
        self.showFullScreen() 
        self.maindesign()

    def maindesign(self):
        """Method to design main page"""
        ####Label###
        self.admin_header = QLabel("Admin Panel", self)
        self.admin_header.setStyleSheet("font-size:40px")
        self.admin_header.move(130, 10)
        self.admin_header.show()

当我点击按钮时代码工作正常但是当我按下机械按钮时，代码冻结并显示错误消息。

Answer 1

registerKeyPressHandler 分配的处理程序在监视键的线程中执行，在您的情况下，printKey 在您尝试创建小部件但被 Qt 禁止的辅助线程中执行。

解决方案是创建一个 QObject 并通过发送按下的键来发出信号（因为信号是线程安全的），然后连接到接收信息的插槽：

from PyQt5.QtCore import pyqtSignal, pyqtSlot, QObject
from PyQt5.QtWidgets import QLabel, QPushButton, QWidget

from pad4pi import rpi_gpio


class KeypadManager(QObject):
    keyPressed = pyqtSignal(object)

    def __init__(self, parent=None):
        super().__init__(parent)
        factory = rpi_gpio.KeypadFactory()
        self._keypad = factory.create_4_by_4_keypad()
        self._keypad.registerKeyPressHandler(self._key_press_handler)

    def _key_press_handler(self, key):
        self.keyPressed.emit(key)


class DigitalClock(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("OM SAI RAM")
        self._keypad_manager = KeypadManager()
        self._keypad_manager.keyPressed.connect(self.printKey)

        # self.setCursor(Qt.BlankCursor)
        button = QPushButton("Click", self)
        button.clicked.connect(self.show_authentication_page)
        button.move(10, 10)

        self.showFullScreen()

    def show_authentication_page(self):
        self.newpage = Authentication_page()
        self.close()

    @pyqtSlot(object)
    def printKey(self, key):
        if key == "A":
            self.show_authentication_page()


class Authentication_page(QWidget):
    # ...

尝试在 pyqt5 gui 应用程序中使用 4x4 键盘

trying to use 4x4 keypad with pyqt5 gui application

python

pyqt

qthread

python-3.x

pyqt5