kivy: Etikettentext des dynamisch generierten Etiketts ändern

Question

Am Ende sollte der labels.text Sensordaten anzeigen. Die Daten werden in einem separaten Prozess generiert und über eine Pipe an kivy übergeben. Derzeit versuche ich ein sehr einfaches Minimalbeispiel zu implementieren. Allerdings bekomme ich meinen Kopf nicht um das Update-Konzept für dynamisch generierte Etiketten:

from math import sin 

""" 
Activate the touch keyboard. It is important that this part is on top 
because the global config should be initiated first. 
""" 
from kivy.config import Config 
Config.set('kivy', 'keyboard_mode', 'multi') 

from kivy.app import App 

from kivy.clock import Clock 
# The Builder is used to define the main interface. 
from kivy.lang import Builder 

from kivy.properties import StringProperty, ObjectProperty, NumericProperty 
from kivy.uix.label import Label 
from kivy.uix.screenmanager import ScreenManager, Screen 
from kivy.uix.stacklayout import StackLayout 


import numpy as np 

class MainScreen(Screen): 
    pass 


class DataScreen(Screen): 

    def __init__(self, **kwargs): 
     layout = StackLayout() 
     super(DataScreen, self).__init__(**kwargs) 
     self.n_probes = 8 
     self.label_text = [] 
     for i in range(self.n_probes): 
      self.label_text.append(StringProperty()) 
      self.label_text[i] = str(i) 

     for i in range(self.n_probes): 
      l = Label(id='l_{}'.format(i), 
         name='l_{}'.format(i), 
         text=self.label_text[i], 
         font_size='60sp', 
         height=20, 
         width=20, 
         size_hint=(0.5, 0.2)) 
      self.ids.stack.add_widget(l) 

    def change_text(self): 
     for i in range(self.n_probes): 
      self.label_text[i] = str(2) 



Builder.load_file('phapp.kv') 

class MyApp(App): 
    """ 
    The settings App is the main app of the pHBot application. 
    It is initiated by kivy and contains the functions defining the main interface. 
    """ 


    def build(self): 
     """ 
     This function initializes the app interface and has to be called "build(self)". 
     It returns the user interface defined by the Builder. 
     """ 

     sm = ScreenManager() 
     sm.add_widget(MainScreen()) 
     sm.add_widget(DataScreen()) 
     # returns the user interface defined by the Builder 
     return sm 


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

Die .kv Datei:

<MainScreen>: 
    name: 'main' 
    BoxLayout: 
     orientation: 'vertical' 
     Button: 
      text: 'Go to data' 
      font_size: 40 
      on_release: app.root.current = 'data' 
     Button: 
      text: 'Exit' 
      font_size: 40 
      on_release: app.stop() 

<DataScreen>: 
    name: 'data' 
    StackLayout: 
     id: stack 
     orientation: 'lr-tb' 
    BoxLayout: 
     Button: 
      size_hint: (0.5, 0.1) 
      text: 'Update' 
      font_size: 30 
      on_release: root.change_text() 
     Button: 
      size_hint: (0.5, 0.1) 
      text: 'Back to main menu' 
      font_size: 30 
      on_release: app.root.current = 'main' 

Die Etiketten werden mit dieser Version zu aktualisieren. Irgendwelche Ideen warum?

Answer 1

Diese Version funktioniert. Ich weiß immer noch nicht, warum das erste nicht geklappt hat. Vielleicht muss es mit dem Umfang etwas zu tun haben? Wenn ich alles statisch in der .kv-Datei und der .py-Datei (z. B. wie in diesem SO post) code alles funktioniert gut.

from math import sin 

""" 
Activate the touch keyboard. It is important that this part is on top 
because the global config should be initiated first. 
""" 
from kivy.config import Config 
Config.set('kivy', 'keyboard_mode', 'multi') 

from kivy.app import App 

from kivy.clock import Clock 
# The Builder is used to define the main interface. 
from kivy.lang import Builder 

from kivy.properties import StringProperty, ObjectProperty, NumericProperty 
from kivy.uix.label import Label 
from kivy.uix.screenmanager import ScreenManager, Screen 
from kivy.uix.stacklayout import StackLayout 


import numpy as np 

class MainScreen(Screen): 
    pass 


class DataScreen(Screen): 

    def __init__(self, **kwargs): 
     layout = StackLayout() 
     super(DataScreen, self).__init__(**kwargs) 
     self.n_probes = 8 
     self.label_text = [] 
     for i in range(self.n_probes): 
      self.label_text.append(StringProperty()) 
      self.label_text[i] = str(i) 
     self.l = [] 
     for i in range(self.n_probes): 
      self.l.append(Label(id='l_{}'.format(i), 
          text='Start {}'.format(i), 
          font_size='60sp', 
          height=20, 
          width=20, 
          size_hint=(0.5, 0.2))) 
      self.ids.stack.add_widget(self.l[i]) 

    def change_text(self): 
     for i in range(self.n_probes): 
      self.l[i].text = 'Update' + str(2) 


Builder.load_file('phapp.kv') 

class MyApp(App): 
    """ 
    The settings App is the main app of the pHBot application. 
    It is initiated by kivy and contains the functions defining the main interface. 
    """ 


    def build(self): 
     """ 
     This function initializes the app interface and has to be called "build(self)". 
     It returns the user interface defined by the Builder. 
     """ 

     sm = ScreenManager() 
     sm.add_widget(MainScreen()) 
     sm.add_widget(DataScreen()) 
     # returns the user interface defined by the Builder 
     return sm 


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


<MainScreen>: 
    name: 'main' 
    BoxLayout: 
     orientation: 'vertical' 
     Button: 
      text: 'Go to data' 
      font_size: 40 
      on_release: app.root.current = 'data' 
     Button: 
      text: 'Exit' 
      font_size: 40 
      on_release: app.stop() 

<DataScreen>: 
    name: 'data' 
    StackLayout: 
     id: stack 
     orientation: 'lr-tb' 
    BoxLayout: 
     Button: 
      size_hint: (0.5, 0.1) 
      text: 'Update' 
      font_size: 30 
      on_release: root.change_text() 
     Button: 
      size_hint: (0.5, 0.1) 
      text: 'Back to main menu' 
      font_size: 30 
      on_release: app.root.current = 'main'