KivyMD implementation of Modern Design confirmation dialog.

confirmation.py

from kivy.app import App
from kivy.clock import Clock
from kivy.properties import (
    ListProperty, DictProperty, StringProperty, BooleanProperty)
from kivymd.theming import ThemeManager
from kivy.lang import Builder

from kivymd.uix.dialog import MDDialog
from kivymd.uix.list import OneLineIconListItem, ILeftBodyTouch
from kivymd.uix.selectioncontrol import MDCheckbox
from kivy.uix.behaviors.togglebutton import ToggleButtonBehavior


COUNTRIES = {
    'RU': 'Russian Federation', 'SE': 'Sweden', 'US': 'United States',
}


KV = """
<-ContentMDDialog>
    orientation: 'vertical'
    padding: dp(15)
    spacing: dp(10)
    text_button_ok: ''
    text_button_cancel: ''

    MDLabel:
        id: title
        text: root.title
        font_style: 'H6'
        halign: 'left' if not root.device_ios else 'center'
        valign: 'top'
        size_hint_y: None
        text_size: self.width, None
        height: self.texture_size[1]

    RecycleView:
        id: rv
        key_viewclass: 'viewclass'
        key_size: 'height'

        RecycleBoxLayout:
            padding: dp(10)
            default_size: None, dp(48)
            default_size_hint: 1, None
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'

    MDSeparator:
        id: sep

    BoxLayout:
        id: box_buttons
        size_hint_y: None
        height: dp(20)
        padding: dp(20), 0, dp(20), 0


BoxLayout:

    Button:
        text: "Example"
        on_press: app.show_dialog()
"""


class CheckboxItem(ILeftBodyTouch, MDCheckbox):
    pass


class CheckboxIconListItem(OneLineIconListItem):
    """List item with a checkbox/radiobutton to the left.

    Attributes
    ----------
    key : str
        Option key code
    active : bool
        Checkbo pre-selection.
    group : str
        Group name for radiobuttons.

    """
    key = StringProperty(None)
    active = BooleanProperty(False)
    group = StringProperty(None)

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        Clock.schedule_once(self._finish_init, 0)

    def _finish_init(self, dt):
        self.add_widget(CheckboxItem(
            id=self.key,
            active=self.active,
            group=self.group
        ))

    def on_release(self):
        box = self.ids._left_container.children[0]
        active = box.active
        if box.group:
            for cb in ToggleButtonBehavior.get_widgets(box.group):
                cb.active = False
        box.active = not active


class ConfirmationDialog(MDDialog):
    """Material Design Confirmation dialog.

    Attributes
    ----------
    options : dict
        Key/value of options to choose from.
    preselected : list
        Keys of pre-selected options.
    group : str
        Group name for radiobuttons, leave blank for checkboxes.
    choosen : list
        Result of the choosen options.

    """
    options = DictProperty({})
    preselected = ListProperty([])
    group = StringProperty(None)
    choosen = ListProperty([])

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

        for opt in self.options:
            self.children[0].ids.rv.data.append({
                "viewclass": "CheckboxIconListItem",
                "text": self.options[opt],
                "key": opt,
                "active": (True if opt in self.preselected else False),
                "group": self.group,
                "divider": None,
            })

    def get_choices(self):
        for ic in self.children[0].ids.rv.children[0].children:
            cb = ic.ids._left_container.children[0]
            if cb.active:
                self.choosen.append(cb.id)
        return self.choosen


class Test(App):
    theme_cls = ThemeManager()

    def build(self):
        return Builder.load_string(KV)

    def show_dialog(self):
        ConfirmationDialog(
            title="Which country?",
            size_hint=(0.5, 0.4),
            options=COUNTRIES,
            group='country',
            events_callback=lambda x, y: print(y.get_choices())
        ).open()


Test().run()