python学习 之 pyqt5前后端分离试验（热电偶温度读取）

1. 代码（根据平台获取数据来源）

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *

from threading import Thread
import time, sys, os
import qdarkstyle
# 导入随机数
import random

import matplotlib

matplotlib.use('Qt5Agg')
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import matplotlib.pyplot as plt


# 获取当前系统架构
def get_platform():
    if sys.platform.startswith('win'):
        return 'win'
    elif sys.platform.startswith('linux'):
        return 'linux'
    else:
        return 'other'


PLATFORM = get_platform()

# 根据系统架构选择是否导入温度计库
if PLATFORM == 'linux':
    import busio
    import digitalio
    import board
    from adafruit_bus_device.spi_device import SPIDevice

# 切换到当前目录
os.chdir(os.path.dirname(os.path.abspath(__file__)))


# 自定义信号源对象类型，一定要继承自 QObject
class MySignals(QObject):
    updateTempSingle = pyqtSignal(QProgressBar, float)


temp_examples = [77.6, 89.7, 89.1, 88.9, 88.5, 90.4, 91.5, 93.3,
                 96.3, 100.4, 107.2, 114.3, 119.4, 126.9, 135.2,
                 141.8, 145.1, 148.6, 152.3, 154.7, 156.4, 160.9,
                 162.9, 164.7, 165.9, 167.7, 169.6, 171.3, 172,
                 172.8, 174.2, 175.4, 175.7, 176.6, 177.2, 178.8,
                 178.9, 180.4, 180.7, 181.8, 182.4, 183.8, 185.8,
                 188.4, 192.4, 195, 195.7, 197.4, 198.8, 199.6,
                 200, 199.9, 199.5, 198.8, 197.9, 197.4, 196.9,
                 196.9, 196.9, 196.6, 197.3, 196.1, 196.8, 199.6,
                 200.1, 200.5, 200.8, 202.3, 202.6, 203.1, 204.1,
                 205.1, 206, 206.7, 206.7, 206.3, 205.4, 200.7, 198.9 ]

temp_real = []

# 实例化
global_ms = MySignals()


class Temp_Gui(QWidget):

    def __init__(self):
        super(Temp_Gui, self).__init__()

        # 设置图标
        self.setWindowTitle("温度监测")
        self.setWindowIcon(QIcon('./images/head_log.jpg'))
        # self.resize(250, 100)

        StyleSheet = '''
        QWidget{
            text-align: center;
            border: 2px solid #2196F3;
            border-radius: 5px;
            background-color: #E0E0E0;
        },
        '''
        # 设置样式为红色
        # self.setStyleSheet(StyleSheet)
        self.setStyleSheet(qdarkstyle.load_stylesheet_pyqt5())

        self.formLayout = QFormLayout()

        self.LineEdit_temp_value1 = QLineEdit("0 °C")
        self.LineEdit_temp_value2 = QLineEdit("0 °C")
        self.LineEdit_temp_value3 = QLineEdit("0 °C")
        self.LineEdit_temp_value1.setReadOnly(True)
        self.LineEdit_temp_value2.setReadOnly(True)
        self.LineEdit_temp_value3.setReadOnly(True)
        # 设置字体居中
        self.LineEdit_temp_value1.setAlignment(Qt.AlignCenter)
        self.LineEdit_temp_value2.setAlignment(Qt.AlignCenter)
        self.LineEdit_temp_value3.setAlignment(Qt.AlignCenter)

        self.comboBox = QComboBox()
        self.comboBox.addItems(["Software", "Hardware"])
        self.comboBox.setCurrentIndex(0)

        self.figure = plt.figure(1)
        self.canvas = FigureCanvas(self.figure)

        self.formLayout.addRow(QLabel('触发源:'), self.comboBox)
        self.formLayout.addRow(QLabel('热电偶1:'), self.LineEdit_temp_value1)
        self.formLayout.addRow(QLabel('热电偶2:'), self.LineEdit_temp_value2)
        self.formLayout.addRow(QLabel('热电偶3:'), self.LineEdit_temp_value3)

        self.Widget_temp_graph = QWidget()

        self.Widget_temp_graph.setLayout(self.formLayout)

        self.VBoxLayout = QVBoxLayout()
        self.VBoxLayout.addWidget(self.Widget_temp_graph)
        self.VBoxLayout.addWidget(self.canvas)
        self.setLayout(self.VBoxLayout)

        # # ax = self.figure.add_axes([0.1,0.1,0.8,0.8])
        # plt.plot(temp_examples)
        # self.canvas.draw()

        # 自定义信号的处理函数, 传出去给MySignals，再传回来给控件
        global_ms.updateTempSingle.connect(self.updataTemperature)

    def updataTemperature(self, object, value):
        if (value > 1000):
            object.setText("Max °C")
        else:
            object.setText("%.2f °C"%(value))


def readTempTask():
    def threadFunc():
        if PLATFORM == 'win':
            while True:
                time.sleep(0.22)
                # 发出信号，通知主线程进行进度处理
                global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value1, random.uniform(25, 28))
                global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value2, random.uniform(25, 28))
                global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value3, random.uniform(25, 28))

                temp_real.append(random.uniform(25, 28))
                plt.plot(temp_real)
                temp_gui.canvas.draw()

        elif PLATFORM == 'linux':
            with busio.SPI(board.SCLK, board.MOSI, board.MISO) as spi_bus:
                cs1_pin = digitalio.DigitalInOut(board.SPI1_CS)
                cs2_pin = digitalio.DigitalInOut(board.PC7)
                cs3_pin = digitalio.DigitalInOut(board.PC10)
                MAX6675_1 = SPIDevice(spi_bus, cs1_pin, baudrate=1_000_000)
                MAX6675_2 = SPIDevice(spi_bus, cs2_pin, baudrate=1_000_000)
                MAX6675_3 = SPIDevice(spi_bus, cs3_pin, baudrate=1_000_000)
                while True:
                    bytes_read1 = bytearray(2)
                    bytes_read2 = bytearray(2)
                    bytes_read3 = bytearray(2)
                    with MAX6675_1 as spi:
                        spi.readinto(bytes_read1)
                    high_bit = bytes_read1[0] * 32
                    low_bit = (bytes_read1[1] & 0b11111000) >> 3
                    Temp1 = (high_bit + low_bit) * 0.25
                    with MAX6675_2 as spi:
                        spi.readinto(bytes_read2)
                    high_bit = bytes_read2[0] * 32
                    low_bit = (bytes_read2[1] & 0b11111000) >> 3
                    Temp2 = (high_bit + low_bit) * 0.25
                    with MAX6675_3 as spi:
                        spi.readinto(bytes_read3)
                    high_bit = bytes_read3[0] * 32
                    low_bit = (bytes_read3[1] & 0b11111000) >> 3
                    Temp3 = (high_bit + low_bit) * 0.25
                    # print("Temperatures: %.2f C, %.2f C, %.2f C;" % (Temp1, Temp2, Temp3))
                    # print("Temperatures: %.2f C;" % (Temp1))

                    global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value1, Temp1)
                    global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value2, Temp2)
                    global_ms.updateTempSingle.emit(temp_gui.LineEdit_temp_value3, Temp3)

                    # 注意MAX6675数据手册有说明，芯片的转换时间典型值为0.17s，最大值为0.22s
                    time.sleep(0.22)

                    temp_real.append(Temp1)
                    plt.plot(temp_real)
                    temp_gui.canvas.draw()

    thread = Thread(target=threadFunc, daemon=True)
    thread.start()


if __name__ == '__main__':
    # pyqt5设置默认字体为"./font/simkai.ttf"
    app = QApplication(sys.argv)
    font_path = "./font/simkai.ttf"
    QFontDatabase.addApplicationFont(font_path)
    app.setFont(QFont(font_path))
    # 设置字体加粗
    app.setStyleSheet("QWidget{font-weight:bold;font-size:18px;}")
    temp_gui = Temp_Gui()
    temp_gui.show()
    readTempTask()
    sys.exit(app.exec_())

2. 运行图片