python - 为什么从 pyserial 读取值时没有发出我的 QThread 信号？

Question

我正在尝试创建一个 pyqtgraph，它根据它从 pyserial 连接接收到的值实时更新。目前我有两个文件：一个从 pyserial 连接读取数据并在两个值发生更改时发出信号，另一个文件解释信号并显示两个更改的值。由于某种原因，从 pyserial 连接读取的值不会发送到第二个文件。按下启动 QPushButton 启动线程。我引用了这篇文章，但我无法弄清楚为什么信号存在问题，所以任何建议都将不胜感激。提前谢谢！

这是第一个文件：

class PortCommunication(QThread):

    # Define signal for thread communication
    data_changed = pyqtSignal(float, float)

    def run(self):
        try:
            # Define port settings
            with serial.Serial(
                port = "COM4",
            baudrate = 9600,
            bytesize = 8,
            parity = serial.PARITY_NONE,
            stopbits = 1,
            timeout = 1,
                ) as self.ser:

                count = 0
                # test only 10 iterations 
                while count < 10:           
                    count += 1
      
                    self.ser.write(b"ADC0\r\n")

                    # Get device output (should be ['#,#,#'])
                    output = self.ser.read(size=20)
                    decoded_output = (output.decode('utf-8'))

                    # Turn the decoded_output from string to list
                    final_list = decoded_output.strip().split(',')
                   
                    # Torque is the first number in the ['#', '#', '#']
                    torque = float(final_list[0])
                    speed = float(final_list[1])
                    
                    # Emit torque and speed signal
                    #print(torque, speed)        
                    self.data_changed.emit(torque, speed)
                    time.sleep(3)
                    
        except serial.serialutil.SerialException:
            print("Couldn't open port.")

这是第二个文件：

class MainWidget(QtGui.QWidget):

    def __init__ (self):                   
        super(MainWidget, self).__init__()       
        self.initializeSpace()
        
    def initializeSpace(self):        
        # Create and define buttons that will control the thread
        self.start = QtGui.QPushButton("Start")
        self.start.clicked.connect(self.startEvent)
        self.stop = QtGui.QPushButton("Stop")

        # Create Layout
        self.layout = QtGui.QGridLayout()
       
        # Add widgets to layout
        self.layout.addWidget(self.start, 0, 0)
        self.layout.addWidget(self.stop, 1, 0)

        # Set layout
        self.setLayout(self.layout)

    def startEvent(self):
        # Create a thread
        self.thread = PortCommunication()
        self.thread.start()
        # Connect signals & slots 
        self.thread.data_changed.connect(self.display_data)

    def display_data(self, torque, speed):
        print(torque, speed)