kulo.py

kulo.py

import functools
from dataclasses import dataclass

from kivy.app import App
from kivy.lang import Builder
from kivy.properties import (
    BooleanProperty,
    ColorProperty,
    ListProperty,
    StringProperty,
)
from kivy.uix.behaviors import ButtonBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label


KV = '''
<PostLine>
    text: 'Title: {}'.format(self.title)
    background_color: (1, 1, 0, 1) if not self.liked else (1, 0, 0, 1)
    size_hint_y: None
    height: dp(45)

    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            size: self.size
            pos: self.pos


<PostsList>:
    RecycleView:
        data: root._data
        viewclass: 'PostLine'

        RecycleBoxLayout:
            orientation: 'vertical'
            spacing: dp(10)
            size_hint_y: None
            height: self.minimum_size[1]
            default_size_hint: 1, None
            default_size: None, None


PostsList:
    posts: app.posts
    on_post_liked: app.on_post_liked(args[1], args[2])
'''


@dataclass
class Post:
    id: int
    title: str
    liked: bool


class PostLine(ButtonBehavior, Label):
    __events__ = ('on_post_liked',)

    title = StringProperty()
    liked = BooleanProperty(False)
    background_color = ColorProperty()

    def on_press(self):
        self.dispatch('on_post_liked', not self.liked)

    def on_post_liked(self, liked):
        pass


class PostsList(BoxLayout):
    __events__ = ('on_post_liked',)

    posts = ListProperty()

    _data = ListProperty()

    def on_posts(self, *args):
        self._update_data()

    def _update_data(self):
        self._data = [
            dict(
                title=post.title,
                liked=post.liked,
                on_post_liked=functools.partial(
                    self.dispatch,
                    'on_post_liked',
                    post.id,
                ),
            )
            for post in self.posts
        ]

    def on_post_liked(self, post_id, liked):
        self._update_data()


class MainApp(App):
    posts = ListProperty()

    def build(self):
        self.posts = [
            Post(
                id=i,
                title='Hello ' + str(i),
                liked=(i % 6 == 0),
            )
            for i in range(1, 21)
        ]
        return Builder.load_string(KV)

    def on_post_liked(self, post_id, liked):
        for post in self.posts:
            if post.id == post_id:
                post.liked = liked
                break


MainApp().run()