无法使ObjectProperty在python中与Kivy一起工作

Question

一段时间以来，我一直在努力寻找解决方案。我不想在python中创建按钮，因为我试图使样式远离功能。每次我尝试使用对象属性时，它都会报告此错误。我已经在stackoverflow上搜索了很多解决方案，所以我希望有人能帮助我

TypeError: bind() takes exactly 2 positional arguments (0 given)

至于实际代码，下面是python：

# Function import libraries
import sys
import json
import googlemaps
import pygatt
import time
import asyncio
from bleak import discover
from urllib.request import urlopen
from twilio.rest import Client
import asynckivy as ak
from asynckivy.process_and_thread import \
    thread as ak_thread, process as ak_processt


# UI import libraries
from kivy.app import App
from  kivy.properties import ObjectProperty
from kivy.properties import StringProperty
from kivy.uix.widget import Widget
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput
from kivy.uix.button import Button
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.label import Label
from kivy.uix.image import Image
from functools import partial
from kivy.event import EventDispatcher

class Screen1(Screen):
    def __init__ (self,**kwargs):
        super (Screen1, self).__init__(**kwargs)

        pairbtn = ObjectProperty(None)
        pairbtn.bind(on_press=self.pair_pressed)
        # self.add_widget(pairbtn)

    def pair_pressed(self, event):
        async def run():
            devices = await discover()
            for d in devices:
                print(d)
                if (str(d).find('DSD TECH') != -1):
                    address = str(d)[0:17]
                    print("Device Discovered" + address)
                    exit()
        loop = asyncio.get_event_loop()
        loop.run_until_complete(run())




class Screen2(Screen):
    pass



class esosApp(App):
    def build(self):
        screen_manager = ScreenManager()
        screenone = Screen1(name='s1')
        screentwo = Screen2(name='s2')

        screen_manager.add_widget(screenone)
        screen_manager.add_widget(screentwo)

        return screen_manager    


if __name__ == '__main__':
    esosApp().run() 

这是kv文件（屏幕2省略）：

#:kivy 1.11.1

<Screen1>:

    orientation: "vertical"
    pairbtn: pairbtn

    canvas.before:
        Color:

            rgb: 0.965,0.965, 0.965
        Rectangle:
            pos: self.pos
            size: self.size
    Image:
        source: 'icon.png'
        size: self.texture_size
    AnchorLayout:
        anchor_y: 'top'
        BoxLayout:
            size_hint: 1,.07

            canvas.before:
                Color:
                    rgb: 0.6745 , 0.8353 , 0.8784
                Rectangle:
                    pos: self.pos
                    size: self.size
            Image:
                source: 'Logo.PNG'
                size: self.texture_size
        AnchorLayout:
            anchor_x: 'center'
            anchor_y: 'bottom'
            padding: (0, 10, 0, 10)

            Button:
                id: pairbtn
                text: "Pair Device"
                background_normal: ''
                background_color: 0.6745 , 0.8353 , 0.8784, 1
                size_hint: (.8, .1)

Answer 1

属性不应该也不能在类的方法中声明，而是在方法的同一级别上声明，例如：

class Foo(Base):
    prop = XProperty(default_value)

    def __init__(self, **kwargs):
        super().__init__(self, **kwargs)
    # ...

很明显，您的代码不符合该条件，并且您的逻辑pairbtn为None，因此您无法使用on_press进行绑定，最后最简单的事情是使用kv进行连接：

# ...
Button:
    id: pairbtn
    text: "Pair Device"
    background_normal: ''
    background_color: 0.6745 , 0.8353 , 0.8784, 1
    size_hint: (.8, .1)
    on_press: root.pair_pressed()