如何每秒更新 Kivy 中的標簽

Question

你好開發者，來自奧地利的問候

目前，我正在嘗試弄清楚如何永久更新 Kivy 界面中的標簽。

情況：對於我的畢業論文，我必須為駕駛機器人開發 GUI。 在這個用戶界面中，有一個標簽應該顯示機器人的當前速度。 速度由 Raspberry PI 測量並使用套接字發送到用戶界面

我已經設法更改了標簽，但前提是界面中的操縱桿被移動了。

def _update_joystick_output(self, instance, pad):   #send joystick data
    global driving_assistant
    global connection_check_rpi
    global joystick_data
    global m
    m = str(instance.magnitude)[0:5]
    a = str(instance.angle)[0:5]
    joystick_data=m+" "+a
    self.root.update_label(m)  #This command updates the label in the Interface
    if connection_check_rpi == True:
        if(len(joystick_data) <= 12):
            s1.send(str.encode(joystick_data))

我已經嘗試編寫一個線程，它以與上面相同的方式每半秒自動更新一次標簽，但它在任何情況下都不起作用。

class Velocity(threading.Thread):
def run(self):
    global vel
    global s1
    global connection_check_rpi

    self.root = Interface()

    while True:
        if connection_check_rpi == True:

            try:
                rpm_data = s1.recv(1024)
                vel = rpm_data.decode('utf-8')
                self.root.update_label
            except:
                break
        else:
            break

這是完整的代碼（不要介意縮進）

import threading
import time
import socket

from kivy.config import Config
from kivy.app import App
from kivy.garden.joystick import Joystick
from kivy.uix.floatlayout import FloatLayout
from kivy.lang import Builder
from kivy.clock import Clock
from kivy.uix.label import Label
from kivy.properties import StringProperty
from kivy.core.window import Window

Window.clearcolor = (1,  1,  1,  1)

global connection_check_rpi
global connection_check_cam
global driving_assistant
global vel
global m
global cruise_control
global tempHelper
global test_check

vel = 0
tempHelper = 0

driving_assistant=False
cruise_control = False
test_check=False
connection_check_rpi=False
connection_check_cam=False

presentation = Builder.load_string(        #place all objects in GUI
"""
#File name: accept_SSCc.py
#: import Joystick kivy.garden.joystick.Joystick

<Interface>:
    Image:
        id: pic
        source:'c:/python/bg.png'
        pos: root.width/2-60, root.height/2-50
    Label:
        id: con1
        text: '[color=010203]'+root.connection1+'[/color]'
        pos: root.width/2-60, -root.height/2+40
        markup: True
    Label:
        id: con2
        text: '[color=010203]'+root.connection2+'[/color]'
        pos: root.width/2-67, -root.height/2+15
        markup: True
    Label:
        id: auto
        text: '[size=20][color='+root.colorauto+']'+root.auto_label+'[/color][/size]'
        pos: 0, -root.height/2+70
        markup: True
    Label:
        id: rpm
        text: '[size=40][color=0039FF]'+root.rpm+'[/color][/size]'
        pos: 0, -root.height/2+120
        markup: True
    Label:
        id: cc
        text: '[size=20][color='+root.colorcc+']'+root.cc_label+'[/color][/size]'
        pos: 0, -root.height/2+50
        markup: True
    Label:
        id: value
        text: '[size=20][color=000000]'+root.cc_value+'[/color][/size]'
        pos: root.width/2-170, -root.height/2+200
        markup: True
    Button:
        text: "ANBS"
        font_size: 40
        size_hint: None, None
        size: 175, 120
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2-320, 2*root.height/7-110
        on_press: root.button_auto()
    Button:
        text: "CC"
        font_size: 40
        size_hint: None, None
        size: 180, 60
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2+140, 2*root.height/7-50
        on_press: root.button_cc()
    Button:
        text: "+"
        font_size: 40
        size_hint: None, None
        size: 90, 60
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2+140, 2*root.height/7-110
        on_press: root.button_faster()
    Button:
        text: "-"
        font_size: 40
        size_hint: None, None
        size: 90, 60
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2+230, 2*root.height/7-110
        on_press: root.button_slower()
    Button:
        text: "sh"
        font_size: 40
        size_hint: None, None
        size: 200, 70
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2+120, 1.7*root.height/2-10
        on_press: root.button_sh()
    Button:
        text: "dc"
        font_size: 40
        size_hint: None, None
        size: 200, 70
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2-100, 1.7*root.height/2-10
        on_press: root.button_dc()
    Button:
        text: "con"
        font_size: 40
        size_hint: None, None
        size: 200, 70
        color: (1, 1, 1, 1)
        background_color:(0, 0, 0, 1)
        pos: root.width/2-320, 1.7*root.height/2-10
        on_press: root.button_con()
    Joystick:
        outer_size: 0.5
        inner_size: 0.25
        pad_size:   0.5
        outer_line_width: 0.01
        inner_line_width: 0.01
        pad_line_width:   0.01
        outer_background_color: (0.5, 0, 0, 1)
        outer_line_color:       (0, 0, 0, 1)
        inner_background_color: (0.2,  0,  0, 1)
        inner_line_color:       (0,  0,  0,  1)
        pad_background_color:   (0,  0,  0,  0.96)
        pad_line_color:         (1,  0,  0,  0.5)
        size_hint: 0.5, 0.5
        pos: root.width/4, root.height/4+20
 """)

class Interface(FloatLayout):
    connection1=StringProperty()
    connection2=StringProperty()
    auto_label=StringProperty()
    cc_label = StringProperty()
    rpm = StringProperty()
    colorcc = StringProperty()
    colorauto = StringProperty()
    cc_value = StringProperty()

    def __init__(self, **kwargs):
        global vel
        super(Interface, self).__init__(**kwargs)
        self.connection1 = "              rpi: dc"
        self.connection2 = "               cam: dc"
        self.auto_label = "Notbremssystem off"
        self.cc_label = "CruiseControl off"
        self.stop_platzhalter = ""
        self.rpm = str(vel)+" km/h"
        self.colorauto = "FF0000"
        self.colorcc = "FF0000"
        self.cc_value = "Control: None"

    def button_test(self, *args):
        global connection_check_rpi
        global connection_check_cam
        global command
        global test_check
        global s1
        global joystick_data

        if connection_check_rpi == True:
            if test_check==False:
                test_check = True
                command="test_on"
                s1.send(str.encode(command))
                joystick_data = "1.0 90"
                print(joystick_data)
                s1.send(str.encode(joystick_data))
            elif test_check==True:
                test_check=False
                command="test_off"
                s1.send(str.encode(command))
                joystick_data = "0.0 90"
                print(joystick_data)
                s1.send(str.encode(joystick_data))


    def button_cc(self, *args):
        global connection_check_rpi
        global connection_check_cam
        global command
        global cruise_control
        global s1
        global joystick_data
        global tempHelper

        if connection_check_rpi == True: #gehört noch auf true geändert
            if cruise_control == False:

                cruise_control = True
                command="cc_on"
                s1.send(str.encode(command))

                tempHelper = 6
                print(tempHelper)

                self.cc_label = "CruiseControl on"
                self.colorcc = "009910"
                self.cc_value = "Control: %i km/h" % tempHelper

            elif cruise_control == True:

                cruise_control = False
                command="cc_off"
                s1.send(str.encode(command))

                tempHelper = 0
                print(tempHelper)

                self.cc_label = "CruiseControl off"
                self.colorcc = "FF0000"
                self.cc_value = "Control: None"

    def button_faster(self, *args):
        global connection_check_rpi
        global connection_check_cam
        global cruise_control
        global command
        global s1
        global joystick_data
        global tempHelper

        if connection_check_rpi == True and cruise_control == True: #auf True
            if tempHelper < 10.5:
                tempHelper += 1
                print(tempHelper)
                command="cc_faster"
                s1.send(str.encode(command))
                self.cc_value = "Control: %i km/h" % tempHelper


    def button_slower(self, *args):
        global connection_check_rpi
        global connection_check_cam
        global cruise_control
        global command
        global s1
        global joystick_data
        global tempHelper

        if connection_check_rpi == True and cruise_control == True: #auf True
            if tempHelper > 4.5:
                tempHelper -= 1
                print(tempHelper)
                command="cc_slower"
                s1.send(str.encode(command))
                self.cc_value = "Control: %i km/h" % tempHelper


    def button_sh(*args):               #shut servers down
        global connection_check_rpi
        global connection_check_cam
        global s1
        global s2
        command="sh"
        if connection_check_rpi == True:
            s1.send(str.encode(command))
            s1.close()
        if connection_check_cam == True:
            s2.send(str.encode(command))
            s2.close()
        Smart3DControl().stop()

    def button_dc(self, *args):         #disconnect from server
        global connection_check_rpi
        global connection_check_cam
        global s1
        global s2
        command="dc"
        if connection_check_rpi == True:
            s1.send(str.encode(command))
            s1.close()
            connection_check_rpi=False
        if connection_check_cam == True:
            s2.send(str.encode(command))
            s2.close()
            connection_check_cam=False
        self.connection1 = "              rpi: dc"
        self.connection2 = "               cam: dc"
        print("disconnected")

    def button_auto(self, *args):       #de/activate driving assistant
        global s1
        global s2
        print("auto")
        command="auto"
        if connection_check_rpi == True and connection_check_cam == True:
            s1.send(str.encode(command))
            s2.send(str.encode(command))
            global driving_assistant
            if driving_assistant == False:
                driving_assistant = True
                self.auto_label = "Fahrassistent on"
                self.colorauto = "009910"
            elif driving_assistant == True:
                self.auto_label = "Fahrassistent off"
                self.colorauto = "FF0000"
                driving_assistant = False

    def button_con(self, *args):        #connect to servers
        global connection_check_rpi
        global connection_check_cam
        global s1
        global s2
        print("con")

        host1 = '192.168.42.1'  # raspberry
        port1 = 5560

        host2 = '192.168.42.2'  # camera
        port2 = 5568
        try:

            if connection_check_rpi == False:
                s1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                s1.connect((host1, port1))
                print(str(s1))
                self.connection1=str("rpi: "+host1)

                print("connected to rpi")
                connection_check_rpi=True
                print(s1)
                thread = Velocity()
                thread.start()
                thread1 = Ausgabe()
                thread1.start()

            if connection_check_cam == False:
                s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                s2.connect((host2, port2))
                self.connection2=str("cam: "+host2)

                print("connected to camera")
                connection_check_cam=True
                print(s2)
        except:
            pass

    def update_label(self, m, *args):
        global vel
        global cruise_control
        global s1
        global test_check

        self.cc_label = "CruiseControl off"
        self.colorcc = "FF0000"
        self.cc_value = "Control: None"

        if cruise_control == True:
            command="cc_off"
            s1.send(str.encode(command))
        cruise_control = False

        if test_check == True:
            command="test_off"
            s1.send(str.encode(command))
        test_check = False

        if str(vel)[1:2] is ".":
            vel = str(vel)[:4]
        else:
            vel = str(vel)[:5]
        #print(m)
        if m == 0:
            self.rpm = "0 km/h"
        else:
            self.rpm = str(vel)+" km/h"
        #print(self.rpm)


class Smart3DControl(App):
    global vel
    global m

    def build(self):
        self.root = Interface()
        joysticks = self.get_joystick(self.root)   #assign joystick to variable

        for joystick in joysticks:
            joystick.bind(pad=self._update_joystick_output) #bind function to joystick

    def get_joystick(self, parent):
        joysticks = []
        if isinstance(parent, Joystick):
            joysticks.append(parent)
        elif hasattr(parent, 'children'):
            for child in parent.children:
                joysticks.extend(self.get_joystick(child))
        return joysticks

    def _update_joystick_output(self, instance, pad):   #send joystick data
        global driving_assistant
        global connection_check_rpi
        global joystick_data
        global m
        m = str(instance.magnitude)[0:5]
        a = str(instance.angle)[0:5]
        joystick_data=m+" "+a
        #print(joystick_data)
        self.root.update_label(m)
        if connection_check_rpi == True:
            if(len(joystick_data) <= 12):
                s1.send(str.encode(joystick_data))

class Velocity(threading.Thread):
    def run(self):
        global vel
        global s1
        global connection_check_rpi

        self.root = Interface()

        while True:
            if connection_check_rpi == True:

                try:
                    rpm_data = s1.recv(1024)
                    vel = rpm_data.decode('utf-8')
                    self.root.update_label
                except:
                    break
            else:
                break

Smart3DControl().run()

Answer 1

一種方法是使用Clock每隔例如 250 毫秒調用一次回調。
將此添加到您的build方法中：

    def build(self):
        self.root = Interface()
        joysticks = self.get_joystick(self.root)   #assign joystick to variable

        for joystick in joysticks:
            joystick.bind(pad=self._update_joystick_output) #bind function to joystick

        from functools import partial
        from kivy.clock import Clock
        Clock.schedule(partial(self.root.update_label, m), .25)