Question

我想在Kivy中创建两个标签，使用来自温度传感器的传感器数据更新其文本。

温度传感器连接到Arduino，Arduino每两秒钟左右以示例格式将其值打印到串行：

A 82.4 （第1行）

B 80.6 （第2行）

A / B包含在每张印刷品中，作为python可以用来区分两者的标识符。

问题是将这些数据导入python并将其附加到标签上。

这是现有的.py：

import kivy

kivy.require('1.10.0')

from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.stacklayout import StackLayout
from kivy.uix.button import Button
from kivy.clock import Clock
from kivy.properties import StringProperty, NumericProperty, ObjectProperty
from digitalclock import DigitalClock
from kivy.animation import Animation

import serial
import time
import opc


class IntroScreen(Screen):
    pass


class ContScreen(Screen):
    pass


class ScreenManagement(ScreenManager):
    pass


#Disregard this, a timer is included in layout
class Timer(Label):
    a = NumericProperty()  # seconds

    def __init__(self, root, instance, duration, bg_color, **kwargs):
        super(Timer, self).__init__(**kwargs)
        self.obj = instance
        self.a = duration
        self.root = root

        self.obj.disabled = True    # disable widget/button
        self.obj.background_color = bg_color
        self.root.add_widget(self)  # add Timer/Label widget to screen, 'cont'

    def animation_complete(self, animation, widget):
        self.root.remove_widget(widget)  # remove Timer/Label widget to screen, 'cont'
        self.obj.background_color = [1, 1, 1, 1]    # reset to default colour
        self.obj.disabled = False   # enable widget/button

    def start(self):
        Animation.cancel_all(self)  # stop any current animations
        self.anim = Animation(a=0, duration=self.a)
        self.anim.bind(on_complete=self.animation_complete)
        self.anim.start(self)

    def on_a(self, instance, value):
        self.text = str(round(value, 1))


class Status(FloatLayout):
    _change = StringProperty()
    _tnd = ObjectProperty(None)

    def update(self, *args):
        self.time = time.asctime()
        self._change = str(self.time)
        self._tnd.text = str(self.time)
        print (self._change)

#Here is where I start referencing Serial Comms, this line is to identify where
#to *send* commands to via a separate identifier.
bone = serial.Serial('/dev/ttyACM0', 9600)


class XGApp(App):
    time = StringProperty()
    sensor1 = NumericProperty(0)
    sensor2 = NumericProperty(0)

    def update(self, *args):
        self.time = str(time.asctime())
    arduino = self.arduino
    data = arduino.read(arduino.inWaiting())
    for line in data.split('\n'):
        try:
            sensor, value = line.strip().split(' ')
        except:
            print("parse error!")
            continue
        if sensor == 'A':
            self.sensor1 = float(value)
        elif sensor == 'B':
            self.sensor2 = float(value)
        else:
            print("unknown data! {}".format(line))

    def build(self):
        try:
            self.arduino = serial.Serial('/dev/ttyACM0', 9600)
        except Exception as e: print(e)

        Clock.schedule_interval(self.update, 1)
        return Builder.load_file("main.kv")


xApp = XGApp()

if __name__ == "__main__":

    xApp.run()

和.kv：

<ContScreen>:
    FloatLayout
        orientation: 'vertical'
        padding: [10,50,10,50]
        spacing: 50

        Label:
            id: 'TempLabel1'
            text: str(app.sensor1)
            color: 1,1,1,1
            font_size: 80
            pos_hint: {'center_x':0.2, 'center_y':0.6}

        Label:
            id: 'TempLabel2'
            text: str(app.sensor1)
            color: 1,1,1,1
            font_size: 80
            pos_hint: {'center_x':0.5, 'center_y':0.6}

.kv中的

稍后：

StackLayout
        orientation: "tb-rl"
        spacing: 15

        Button:
            text: "1"
            size_hint: None, .16
            width: 225
            on_press:
                Timer(root, self, 10, [100, 0, 100, 1.75]).start()
                bone.Write('j'.encode())
                print("One Executed")

TempLabel1和TempLabel2 是我想从传感器更新的两个标签。

Answer 1

完全有可能。但是您缺少一些东西。

您正在尝试运行应用后尝试连接到串行端口，该操作将无法正常运行，因为到达您的应用后该应用将被停止。相反，您想在应用程序运行时执行此部分。我会尝试使用try / except连接到app.build中的arduino。

def build (self):
    try:
        self.arduino = serial.Serial('/dev/ttyACM0')
    exept:
        print("unable to connect to arduino :(")

    Clock.schedule_interval(self.update, 1)
    return Builder.load_file("main.kv")

然后，您要检查update方法中的消息，但不想阻塞，因此只读取缓冲区中等待的数据量。

def update(self, *args):
    arduino = self.arduino
    data = arduino.read(arduino.inWaiting())

然后您进行处理，我假设您的数据类似于：

A value
B value

在这种情况下，您可以解析它并更新相应的变量，例如：

def update(self, *args):
    arduino = self.arduino
    data = arduino.read(arduino.inWaiting()) 
    for line in data.split('\n'):
        try:
            sensor, value = line.strip().split(' ')
        except:
            print("parse error!")
            continue
        if sensor == 'A':
            self.sensor1 = float(value)
        elif sensor == 'B':
            self.sensor2 = float(value)
        else:
            print("unknown data! {}".format(line))

将完成这项工作，这有点简单，因为它假定您总是会获得完整的阵容，但是以后可以根据需要进行改进（根据我的经验，这似乎足够了）。

现在，我们需要确保我们的标签注意到值的变化，为此，kivy使用properties（这是更聪明的属性），您需要在app类上声明它们。

class XGApp(App):
    sensor1 = NumericProperty(0)
    sensor2 = NumericProperty(0)

现在，您可以通过应用实例使更新直接显示值。

<ContScreen>:
    FloatLayout
        orientation: 'vertical'
        padding: [10,50,10,50]
        spacing: 50

        Label:
            id: 'TempLabel1'
            text: str(app.sensor1)
            color: 1,1,1,1
            font_size: 80
            pos_hint: {'center_x':0.2, 'center_y':0.6}

        Label:
            id: 'TempLabel2'
            text: str(app.sensor2)
            color: 1,1,1,1
            font_size: 80
            pos_hint: {'center_x':0.5, 'center_y':0.6}

Kivy-显示实时传感器数据的标签

1 个答案: