electrum-bitcoinprivate/gui/kivy/uix/dialogs/fee_dialog.py

from kivy.app import App
from kivy.factory import Factory
from kivy.properties import ObjectProperty
from kivy.lang import Builder

Builder.load_string('''
<FeeDialog@Popup>
    id: popup
    title: ''
    size_hint: 0.8, 0.8
    pos_hint: {'top':0.9}
    BoxLayout:
        orientation: 'vertical'
        BoxLayout:
            orientation: 'horizontal'
            size_hint: 1, 0.5
            Label:
                text: _('Dynamic fees')
            CheckBox:
                id: dynfees
        BoxLayout:
            orientation: 'horizontal'
            size_hint: 1, 0.5
            Button:
                text: 'Cancel'
                size_hint: 0.5, None
                height: '48dp'
                on_release: popup.dismiss()
            Button:
                text: 'OK'
                size_hint: 0.5, None
                height: '48dp'
                on_release:
                    root.on_ok()
                    root.dismiss()
''')

class FeeDialog(Factory.Popup):

    def __init__(self, config, callback):
        Factory.Popup.__init__(self)
        self.config = config
        self.callback = callback
        self.ids.dynfees.active = bool(self.config.get('dynamic_fees'))

    def on_ok(self):
        self.config.set_key('dynamic_fees', self.ids.dynfees.active, True)
        self.callback()