如何使用来自 USB 串口（来自 Arduino）的数据 refresh/update QLabel？
How do I refresh/update QLabel with data from USB serial (from Arduino)?
我知道这是一个菜鸟问题；原谅我。我为 Cub Scouts 构建了一个 Pinewood Derby 赛车计时器（小型汽车赛道），使用 Arduino 的组合来控制时间和 RasPi 的 GUI 显示车道位置（第 1、2、3 等）和 运行 时间秒（例如“2.1234”）。我在 QT Creator 中有基本的 shell GUI 设置，并通过 USB 成功连接了 Arduino 和 RasPi。我也成功地将 Arduino 串行数据拉入 RasPi（使用单独的小 Python 代码测试）。
我遇到的问题是，一旦 Arduino 通过 USB 触发比赛结果字符串，GUI 中的 QLabel 就会动态更新。换句话说，当比赛开始时，Arduino 发送 "B" 开始（需要 GUI 来清空之前的结果）；比赛结束后，Arduino 发送 "F"，然后发送位置“1”和时间“2.1234”，我需要 Python 到 update/change 每个车道位置和车道时间的相应 QLabel。我确信有一种简单的方法可以做到这一点，但我无法通过搜索这个很棒的网站和其他网站找到方法。
在此先致谢，对于接下来可能出现的 FUBAR 编码，我深表歉意！下面的示例仅显示了一个通道与我将在弄清楚如何执行此操作后使用的 4 个通道。
有两个Python代码我正在使用：
Python 生成的与 QT Creator 交互的代码 XML 代码:
import sys
import time
import serial
from PyQt4 import QtCore, QtGui, uic
global ser
ser=serial.Serial("/dev/ttyUSB1",115200)
ser.flushInput()
qtCreatorFile = "PinewoodDisplay.ui" # Enter file here.
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)
class MyApp(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
Ui_MainWindow.__init__(self)
self.setupUi(self)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
while True:
if ser.inWaiting()>0:
inputValue = (ser.readline().strip())
self.Lane1_Place.setText(inputValue)
XML 从 QT Creator 生成（不确定我是否正确发布）——文件名是 "PinewoodDisplay.ui":
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>619</width>
<height>1051</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<property name="styleSheet">
<string notr="true">background-color: rgb(102, 102, 108)</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QGroupBox" name="Lane1_Group">
<property name="geometry">
<rect>
<x>50</x>
<y>20</y>
<width>481</width>
<height>741</height>
</rect>
</property>
<property name="cursor">
<cursorShape>CrossCursor</cursorShape>
</property>
<property name="autoFillBackground">
<bool>false</bool>
</property>
<property name="styleSheet">
<string notr="true">background-color : rgb(0, 75, 0)</string>
</property>
<property name="title">
<string/>
</property>
<property name="alignment">
<set>Qt::AlignHCenter|Qt::AlignTop</set>
</property>
<layout class="QGridLayout" name="gridLayout">
<item row="2" column="0">
<widget class="QLabel" name="Lane1_Place">
<property name="sizePolicy">
<sizepolicy hsizetype="Expanding" vsizetype="Expanding">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<property name="palette">
<palette>
<active>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</active>
<inactive>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</inactive>
<disabled>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</disabled>
</palette>
</property>
<property name="font">
<font>
<family>Gentium Book Basic</family>
<pointsize>350</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="autoFillBackground">
<bool>false</bool>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="lineWidth">
<number>0</number>
</property>
<property name="text">
<string>4</string>
</property>
<property name="scaledContents">
<bool>true</bool>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
<item row="3" column="0">
<widget class="QLabel" name="Lane1_Time">
<property name="font">
<font>
<pointsize>90</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="text">
<string>4.5678</string>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
<item row="1" column="0">
<widget class="QLabel" name="lblLane1">
<property name="font">
<font>
<pointsize>36</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="text">
<string><html><head/><body><p><span style=" color:#e9e9e9;">Lane 1</span></p></body></html></string>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
</layout>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>619</width>
<height>27</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
<action name="actionTest">
<property name="text">
<string>test</string>
</property>
</action>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
需要读取串行数据的 while True 等阻塞任务对 GUI 不友好，因此您不应该 运行 在同一个线程上，适当的选择是在另一个线程上执行它们, 并通过信号向主线程发送必要的信息。
import sys
import serial
from PyQt4 import QtCore, QtGui, uic
qtCreatorFile = "PinewoodDisplay.ui"
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)
class SerialThread(QtCore.QThread):
dataChanged = QtCore.pyqtSignal(str)
def __init__(self, *args, **kwargs):
QtCore.QThread.__init__(self, *args, **kwargs)
self.ser = serial.Serial("/dev/ttyUSB1",115200)
def run(self):
while True:
if self.ser.inWaiting()>0:
inputValue = self.ser.readline().strip()
self.dataChanged.emit(inputValue)
class MyApp(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
self.setupUi(self)
thread = SerialThread(self)
thread.dataChanged.connect(self.Lane1_Place.setText, QtCore.Qt.QueuedConnection)
thread.start()
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
可以使用 QRunnable 和 QThreadPool 完成相同的任务，也可以使用 QMetaObject::invokeMethod()
发送数据
我知道这是一个菜鸟问题；原谅我。我为 Cub Scouts 构建了一个 Pinewood Derby 赛车计时器（小型汽车赛道），使用 Arduino 的组合来控制时间和 RasPi 的 GUI 显示车道位置（第 1、2、3 等）和 运行 时间秒（例如“2.1234”）。我在 QT Creator 中有基本的 shell GUI 设置，并通过 USB 成功连接了 Arduino 和 RasPi。我也成功地将 Arduino 串行数据拉入 RasPi（使用单独的小 Python 代码测试）。
我遇到的问题是，一旦 Arduino 通过 USB 触发比赛结果字符串，GUI 中的 QLabel 就会动态更新。换句话说，当比赛开始时，Arduino 发送 "B" 开始（需要 GUI 来清空之前的结果）；比赛结束后，Arduino 发送 "F"，然后发送位置“1”和时间“2.1234”，我需要 Python 到 update/change 每个车道位置和车道时间的相应 QLabel。我确信有一种简单的方法可以做到这一点，但我无法通过搜索这个很棒的网站和其他网站找到方法。
在此先致谢，对于接下来可能出现的 FUBAR 编码，我深表歉意！下面的示例仅显示了一个通道与我将在弄清楚如何执行此操作后使用的 4 个通道。
有两个Python代码我正在使用：
Python 生成的与 QT Creator 交互的代码 XML 代码:
import sys
import time
import serial
from PyQt4 import QtCore, QtGui, uic
global ser
ser=serial.Serial("/dev/ttyUSB1",115200)
ser.flushInput()
qtCreatorFile = "PinewoodDisplay.ui" # Enter file here.
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)
class MyApp(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
Ui_MainWindow.__init__(self)
self.setupUi(self)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
while True:
if ser.inWaiting()>0:
inputValue = (ser.readline().strip())
self.Lane1_Place.setText(inputValue)
XML 从 QT Creator 生成（不确定我是否正确发布）——文件名是 "PinewoodDisplay.ui":
<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>619</width>
<height>1051</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<property name="styleSheet">
<string notr="true">background-color: rgb(102, 102, 108)</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QGroupBox" name="Lane1_Group">
<property name="geometry">
<rect>
<x>50</x>
<y>20</y>
<width>481</width>
<height>741</height>
</rect>
</property>
<property name="cursor">
<cursorShape>CrossCursor</cursorShape>
</property>
<property name="autoFillBackground">
<bool>false</bool>
</property>
<property name="styleSheet">
<string notr="true">background-color : rgb(0, 75, 0)</string>
</property>
<property name="title">
<string/>
</property>
<property name="alignment">
<set>Qt::AlignHCenter|Qt::AlignTop</set>
</property>
<layout class="QGridLayout" name="gridLayout">
<item row="2" column="0">
<widget class="QLabel" name="Lane1_Place">
<property name="sizePolicy">
<sizepolicy hsizetype="Expanding" vsizetype="Expanding">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<property name="palette">
<palette>
<active>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</active>
<inactive>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</inactive>
<disabled>
<colorrole role="WindowText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Button">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Text">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="ButtonText">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>255</red>
<green>255</green>
<blue>255</blue>
</color>
</brush>
</colorrole>
<colorrole role="Base">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
<colorrole role="Window">
<brush brushstyle="SolidPattern">
<color alpha="255">
<red>0</red>
<green>75</green>
<blue>0</blue>
</color>
</brush>
</colorrole>
</disabled>
</palette>
</property>
<property name="font">
<font>
<family>Gentium Book Basic</family>
<pointsize>350</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="autoFillBackground">
<bool>false</bool>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="lineWidth">
<number>0</number>
</property>
<property name="text">
<string>4</string>
</property>
<property name="scaledContents">
<bool>true</bool>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
<item row="3" column="0">
<widget class="QLabel" name="Lane1_Time">
<property name="font">
<font>
<pointsize>90</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="text">
<string>4.5678</string>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
<item row="1" column="0">
<widget class="QLabel" name="lblLane1">
<property name="font">
<font>
<pointsize>36</pointsize>
<weight>75</weight>
<bold>true</bold>
</font>
</property>
<property name="styleSheet">
<string notr="true">color: rgb(255, 255, 255)</string>
</property>
<property name="text">
<string><html><head/><body><p><span style=" color:#e9e9e9;">Lane 1</span></p></body></html></string>
</property>
<property name="alignment">
<set>Qt::AlignCenter</set>
</property>
</widget>
</item>
</layout>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>619</width>
<height>27</height>
</rect>
</property>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
<action name="actionTest">
<property name="text">
<string>test</string>
</property>
</action>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
需要读取串行数据的 while True 等阻塞任务对 GUI 不友好，因此您不应该 运行 在同一个线程上，适当的选择是在另一个线程上执行它们, 并通过信号向主线程发送必要的信息。
import sys
import serial
from PyQt4 import QtCore, QtGui, uic
qtCreatorFile = "PinewoodDisplay.ui"
Ui_MainWindow, QtBaseClass = uic.loadUiType(qtCreatorFile)
class SerialThread(QtCore.QThread):
dataChanged = QtCore.pyqtSignal(str)
def __init__(self, *args, **kwargs):
QtCore.QThread.__init__(self, *args, **kwargs)
self.ser = serial.Serial("/dev/ttyUSB1",115200)
def run(self):
while True:
if self.ser.inWaiting()>0:
inputValue = self.ser.readline().strip()
self.dataChanged.emit(inputValue)
class MyApp(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self):
QtGui.QMainWindow.__init__(self)
self.setupUi(self)
thread = SerialThread(self)
thread.dataChanged.connect(self.Lane1_Place.setText, QtCore.Qt.QueuedConnection)
thread.start()
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
可以使用 QRunnable 和 QThreadPool 完成相同的任务，也可以使用 QMetaObject::invokeMethod()