主文件 PyQt4 中的外部函数

Question

我非常努力地使这段代码起作用。我尝试使用 Qtimer、proccesEvents，但没有得到我想要的结果。 GUI 启动，所以有些东西可以工作，但没有任何变化，所以方法 reading() 不起作用。

我在 Whosebug 上搜索了很多以寻求帮助，但找不到。可能是我能力不够

这是代码：

import RPi.GPIO as GPIO
import MFRC522
import signal
import time
from PyQt4 import QtCore, QtGui
from ui_mainwindow import Ui_MainWindow

class MainWindow(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)

        self.ui = Ui_MainWindow()

        self.ui.setupUi(self)

    def reading(self):
        self.ui.processEvents()
        ### Event Functions ###
        continue_reading = True

        # Hook the SIGINT
        signal.signal(signal.SIGINT, end_read)

        # Create an object of the class MFRC522
        MIFAREReader = MFRC522.MFRC522()

        # This loop keeps checking for chips. If one is near it will get the UID and authenticate
        while continue_reading:
            # Scan for cards    
            (status,TagType) = MIFAREReader.MFRC522_Request(MIFAREReader.PICC_REQIDL)

            # Get the UID of the card
            (status,uid) = MIFAREReader.MFRC522_Anticoll()

            # If we have the UID, continue
            if status == MIFAREReader.MI_OK:

                # This is the default key for authentication
                key = [0xFF,0xFF,0xFF,0xFF,0xFF,0xFF]

                # Select the scanned tag
                MIFAREReader.MFRC522_SelectTag(uid)

                # Authenticate
                status = MIFAREReader.MFRC522_Auth(MIFAREReader.PICC_AUTHENT1A, 8, key, uid)

                # Check if authenticated
                if status == MIFAREReader.MI_OK:

                    MIFAREReader.MFRC522_Read(8)

                    self.ui.label_3.show()
                    self.ui.label_2.show()
                    self.ui.label_4.show()
                    self.ui.groupBox.setStyleSheet(_fromUtf8("background: white;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))

                    time.sleep(5)
                    MIFAREReader.MFRC522_StopCrypto1()
                    self.ui.label_3.hide()
                    self.ui.label_2.hide()
                    self.ui.label_4.hide()
                    self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(scan.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))
                else:
                    self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(accsd.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))
                    time.sleep(3)
                    self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(scan.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))

if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    MainWindow = QtGui.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answer 1

你从不调用函数reading()？那为什么要把它放在那里呢？

我不确定你想达到什么目的，但你可以试试：

def __init__(self, parent=None):
    QtGui.QWidget.__init__(self, parent)

    self.ui = Ui_MainWindow()

    self.ui.setupUi(self)

    self.reading() ####################

但是那只会调用一次函数。你希望reading()什么时候执行？

Answer 2

读取数据的任务是阻塞的，所以它不应该运行在 GUI 的线程上，而是在另一个线程上，另一方面，你不应该从另一个线程更改 GUI，而是通过信号如下所示：

import MFRC522
# import signal
import time

from PyQt4 import QtCore, QtGui
from ui_mainwindow import Ui_MainWindow
import threading

class MainWindow(QtGui.QMainWindow):
    state1, state2, state3, state4 = range(4)
    stateChanged = QtCore.pyqtSignal(int)

    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.stateChanged.connect(self.onChangeState)
        threading.Thread(target=self.reading, daemon=True).start()

    def onChangeState(self, state):
        if state == MainWindow.state1:
            self.ui.label_3.show()
            self.ui.label_2.show()
            self.ui.label_4.show()
            self.ui.groupBox.setStyleSheet(_fromUtf8("background: white;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))
        elif state == MainWindow.state2:
            self.ui.label_3.hide()
            self.ui.label_2.hide()
            self.ui.label_4.hide()
            self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(scan.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))

        elif state == MainWindow.state3:
            self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(accsd.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))

        elif state == MainWindow.state4:
            self.ui.groupBox.setStyleSheet(_fromUtf8("background: white url(scan.png) no-repeat center;\n"
                    "border-style: solid;\n"
                    "border-width: 1px;\n"
                    "border-radius: 20px;"))


    def reading(self):
        ### Event Functions ###
        continue_reading = True
        # Hook the SIGINT
        #signal.signal(signal.SIGINT, end_read)
        # Create an object of the class MFRC522
        MIFAREReader = MFRC522.MFRC522()
        # This loop keeps checking for chips. If one is near it will get the UID and authenticate
        while continue_reading:
            # Scan for cards    
            (status,TagType) = MIFAREReader.MFRC522_Request(MIFAREReader.PICC_REQIDL)
            # Get the UID of the card
            (status,uid) = MIFAREReader.MFRC522_Anticoll()

            # If we have the UID, continue
            if status == MIFAREReader.MI_OK:
                # This is the default key for authentication
                key = [0xFF,0xFF,0xFF,0xFF,0xFF,0xFF]
                # Select the scanned tag
                MIFAREReader.MFRC522_SelectTag(uid)
                # Authenticate
                status = MIFAREReader.MFRC522_Auth(MIFAREReader.PICC_AUTHENT1A, 8, key, uid)
                # Check if authenticated
                if status == MIFAREReader.MI_OK:

                    MIFAREReader.MFRC522_Read(8)
                    self.stateChanged.emit(MainWindow.state1)
                    time.sleep(5)
                    MIFAREReader.MFRC522_StopCrypto1()
                    self.stateChanged.emit(MainWindow.state2)

                else:
                    self.stateChanged.emit(MainWindow.state3)
                    time.sleep(3)
                    self.stateChanged.emit(MainWindow.state4)


if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

主文件 PyQt4 中的外部函数

External functions in main file PyQt4

python

pyqt4