Существует пример из команды kivy, который делает именно это. Я думаю, что здесь важен метод on_config_change, который они используют для обновления всех измененных значений - надеюсь, это поможет
"""
Config Example
==============
This file contains a simple example of how the use the Kivy settings classes in
a real app. It allows the user to change the caption and font_size of the label
and stores these changes.
When the user next runs the programs, their changes are restored.
"""
from kivy.app import App
from kivy.uix.settings import SettingsWithTabbedPanel
from kivy.logger import Logger
from kivy.lang import Builder
# We first define our GUI
kv = '''
BoxLayout:
orientation: 'vertical'
Button:
text: 'Configure app (or press F1)'
on_release: app.open_settings()
Label:
id: label
text: 'Hello'
'''
# This JSON defines entries we want to appear in our App configuration screen
json = '''
[
{
"type": "string",
"title": "Label caption",
"desc": "Choose the text that appears in the label",
"section": "My Label",
"key": "text"
},
{
"type": "numeric",
"title": "Label font size",
"desc": "Choose the font size the label",
"section": "My Label",
"key": "font_size"
}
]
'''
class MyApp(App):
def build(self):
"""
Build and return the root widget.
"""
# The line below is optional. You could leave it out or use one of the
# standard options, such as SettingsWithSidebar, SettingsWithSpinner
# etc.
self.settings_cls = MySettingsWithTabbedPanel
# We apply the saved configuration settings or the defaults
root = Builder.load_string(kv)
label = root.ids.label
label.text = self.config.get('My Label', 'text')
label.font_size = float(self.config.get('My Label', 'font_size'))
return root
def build_config(self, config):
"""
Set the default values for the configs sections.
"""
config.setdefaults('My Label', {'text': 'Hello', 'font_size': 20})
def build_settings(self, settings):
"""
Add our custom section to the default configuration object.
"""
# We use the string defined above for our JSON, but it could also be
# loaded from a file as follows:
# settings.add_json_panel('My Label', self.config, 'settings.json')
settings.add_json_panel('My Label', self.config, data=json)
def on_config_change(self, config, section, key, value):
"""
Respond to changes in the configuration.
"""
Logger.info("main.py: App.on_config_change: {0}, {1}, {2}, {3}".format(
config, section, key, value))
if section == "My Label":
if key == "text":
self.root.ids.label.text = value
elif key == 'font_size':
self.root.ids.label.font_size = float(value)
def close_settings(self, settings=None):
"""
The settings panel has been closed.
"""
Logger.info("main.py: App.close_settings: {0}".format(settings))
super(MyApp, self).close_settings(settings)
class MySettingsWithTabbedPanel(SettingsWithTabbedPanel):
"""
It is not usually necessary to create subclass of a settings panel. There
are many built-in types that you can use out of the box
(SettingsWithSidebar, SettingsWithSpinner etc.).
You would only want to create a Settings subclass like this if you want to
change the behavior or appearance of an existing Settings class.
"""
def on_close(self):
Logger.info("main.py: MySettingsWithTabbedPanel.on_close")
def on_config_change(self, config, section, key, value):
Logger.info(
"main.py: MySettingsWithTabbedPanel.on_config_change: "
"{0}, {1}, {2}, {3}".format(config, section, key, value))
MyApp().run()