Python之PyQT多线程串口代码分析

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这篇博客主要记录一下PyQT多线程串口的主要代码分析，文末会有工程的源代码文件
首先，从PyCharm启动QtDesigner

之前给客户做的上位机，保密起见，删减了大部分的框图构件，但不影响本篇串口教程
QtDesigner界面如下：

忽略 添加数据以及表格数据显示，这里用不到
着重讲一下类的构成
新建一个串口类SerialThread，继承自QtCore.QThread，实现全部的串口收发功能

class SerialThread(QtCore.QThread):
    dataReadoutSignal = pyqtSignal(str)    def __init__(self, parent = None, portName = 'COM3', baudrate = 9600, parity = 'N', bytesize = 8, stopbits = 1, timeout = None):
        super(SerialThread, self).__init__(parent)
        self.m_serialPort = serial.Serial()
        self.m_serialPort.port = portName
        self.m_serialPort.baudrate = baudrate
        self.m_serialPort.parity = parity
        self.m_serialPort.bytesize = bytesize
        self.m_serialPort.stopbits = stopbits
        self.m_serialPort.timeout = timeout
        self.OpenScom()    def OpenScom(self):
        try:
            self.m_serialPort.open()
            self.m_serialPort.setRTS(True)
            self.m_serialPort.setDTR(True)        except Exception as ex:
            print(ex)            return ex    def ScomSendOneData(self,datain):
        if isinstance(datain,int):
            listTemp = []
            listTemp.append(datain)
            d = bytes(listTemp)
            self.m_serialPort.write(d)        else:            if isinstance(datain,str):
                d = datain.encode('utf-8')
                self.m_serialPort.write(d)    def ScomGetintData(self):
        n = self.m_serialPort.inWaiting()        if n:
            data = self.m_serialPort.read(n).hex()            #writefile
            print(data)    def ScomGetstrData(self):
        if self.m_serialPort.is_open:
            n = self.m_serialPort.inWaiting()            if n > 0:
                data = self.m_serialPort.read(n).decode('GB2312',errors='ignore')                return data    def run(self):
        cnt = 50

        while cnt <= 3000:
            sendstr = str(cnt)            if len(sendstr) == 2:
                sendstr = '00' + sendstr            else:                if len(sendstr) == 3:
                    sendstr = '0' + sendstr

            self.ScomSendOneData('SET' + sendstr + 'V')
            cnt = cnt + 5
            print('此时设置电压为：' + sendstr + 'V')
            time.sleep(2)

函数功能见名知意，此处不表。这里主要讲一下run函数，run函数实现了一次循环，50到3000步进取5，发送内容是SET0050V到SET3000V，当然，我这样做是业务需求，如果并不需要这个功能，run函数可以写成

    def run(self):
        while true:
            time.sleep(2)

界面我们用QtDesigner制作的ui文件通过pyUIC生成py文件

生成的代码如下（太长，只留前几行）

# -*- coding: utf-8 -*-# Form implementation generated from reading ui file 'CashUpdateUI11v.ui'## Created by: PyQt5 UI code generator 5.6## WARNING! All changes made in this file will be lost!from PyQt5 import QtCore, QtGui, QtWidgetsclass Ui_cash(object):
    def setupUi(self, cash):
    **
    **
    **

此时，新建一个类MyWindow，继承QMainWindow和Ui_cash，并在类内部，创建SerialThread成员
总体代码如下：

class MyWindow(QMainWindow,Ui_cash):
    def __init__(self):
        super(MyWindow,self).__init__()
        self.scomList = []
        self.threadList = []
        self.setupUi(self)
        self.actionOpen.triggered.connect(self.openMsg)
        self.actionSave.triggered.connect(self.saveMsg)
        self.pushButton.clicked.connect(self.ScomAutoFind)
        self.addDataButton.clicked.connect(self.getRHandT)

        self.tableWidget.setColumnCount(5)
        self.tableWidget.setRowCount(1)
        self.tableWidget.setHorizontalHeaderLabels(['11', '22', '33', '44', '55'])
        self.tableRowCnt = 0
        self.tableColumnCnt = 0
        self.ThreadComID = 0
        self.addDatasignal = pyqtSignal(str)
        self.datadict = {'RHldy':0,'Tldy':0,'meaRT':0,'voltport':0}    def getMCUdata(self):
        if self.ThreadComID == 0:
            self.showMsgbox('请先连接串口')        else:
            self.ThreadComID.ScomSendOneData(' 5501AA')
            time.sleep(0.1)
            strt = self.ThreadComID.ScomGetstrData()            if strt is None:
                self.showMsgbox('请将串口线连接到电路板')                return None
            print(strt)
            self.datadict['voltport'] = strt[4:-3] + '.' + strt[-3:-2]
            self.ThreadComID.ScomSendOneData(' 5502AA')
            time.sleep(0.1)
            strt = self.ThreadComID.ScomGetstrData()            if strt is None:
                self.showMsgbox('请将串口线连接到电路板')                return None
            print(strt)
            self.datadict['meaRT'] = strt[4:-4] + '.' + strt[-4:-2]            return 1


    def insertTableNewLine(self):
        self.tableWidget.setItem(self.tableRowCnt, 0, QTableWidgetItem(self.datadict['RHldy']))
        self.tableWidget.setItem(self.tableRowCnt, 1, QTableWidgetItem(self.datadict['Tldy']))
        self.tableWidget.setItem(self.tableRowCnt, 2, QTableWidgetItem(self.datadict['meaRT']))
        self.tableWidget.setItem(self.tableRowCnt, 3, QTableWidgetItem(self.datadict['voltport']))
        self.tableWidget.setItem(self.tableRowCnt, 4, QTableWidgetItem(str(datetime.date.today())+' '+str(datetime.datetime.today().hour)+':'+str(datetime.datetime.today().minute)))
        self.tableRowCnt += 1
        self.tableWidget.insertRow(self.tableRowCnt)    def openMsg(self):
        file,ok = QFileDialog.getOpenFileName(self,"打开记录表","C:/",".txt")    def getRHandT(self):
        if self.ThreadComID == 0:
            self.showMsgbox('请先连接串口')        else:
            data,ok = QInputDialog.getText(self, "露点仪数据", "按如下格式记录：\n  RH空格T\n示例：\n  RH(0~100):66.6\n  T(0~200):9.8\n  输入：66.6 9.8", QLineEdit.Normal, "66.6 9.8" )            if ok == True:
                data = re.findall('^[0-9]+\.[0-9]+\s+[0-9]+\.[0-9]+$', data.rstrip())                if len(data) == 0:
                    self.showMsgbox('数据格式有误，重新录入')                else:
                    data = data[0].split()
                    print(data)
                    self.datadict['RHldy'] = data[0]
                    self.datadict['Tldy'] = data[1]                    if self.getMCUdata() is None:                        return None
                    print(self.datadict)
                    self.insertTableNewLine()            else:
                self.showMsgbox('请重新录入数据')    def showMsgbox(self,strtoshow):
        QMessageBox.warning(self,'提示',strtoshow,QMessageBox.Ok)    def saveMsg(self):
        file,ok = QFileDialog.getSaveFileName(self,"保存记录表","C:/",".txt")    def ScomAutoFind(self):
        self.pushButton.setDisabled(True)
        self.scomList = list(serial.tools.list_ports.comports())        if len(self.scomList) <= 0:
            self.showMsgbox('未发现串口，请检查线缆连接')
            self.pushButton.setDisabled(False)        else:
            comNum = len(self.scomList)
            print(str(comNum) + 'Scom is found')            while comNum:
                comNum = comNum - 1
                if "USB" in str(self.scomList[comNum]):
                    self.ThreadComID = SerialThread(portName=self.scomList[comNum][0])
                    self.ThreadComID.start()
                    self.graphicsView.setStyleSheet("background-color: rgb(0, 255, 0);")
                    print(str(self.scomList[comNum]) + ' is added')

由于我用的是RS232转USB接入电脑，设备名称是USB-SERIAL CH340，当然还有其他RS232转USB芯片，如PL2303等。我这里就单独检查USB是否在设备名称中，没有检查全名，这里要根据实际需求变动

最后就是main了，没什么特别

if __name__ == "__main__":
    app = QApplication(sys.argv)
    myshow = MyWindow()
    myshow.show()    print('程序终止')
    sys.exit(app.exec_())

看一下实际运行效果：
实际运行，（忽略 添加数据 与 数据记录表….）

点击connect后，

当然点击添加数据也是没问题的哈

奉上全部工程文件，链接如下：
https://download.csdn.net/download/ysgjiangsu/10324162

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