Cyclable RecycleView

cyclerv.py

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import NumericProperty


kv = """
<Row@BoxLayout>:
    canvas.before:
        Color:
            rgba: 0.5, 0.5, 0.5, 1
        Rectangle:
            size: self.size
            pos: self.pos
    value: ''
    Label:
        text: root.value

<Test>:
    canvas:
        Color:
            rgba: 0.3, 0.3, 0.3, 1
        Rectangle:
            size: self.size
            pos: self.pos
    RecycleView:
        id: rv
        scroll_type: ['bars', 'content']
        scroll_wheel_distance: dp(114)
        bar_width: dp(10)
        viewclass: 'Row'
        on_scroll_y: root.check_scroll_y(self)
        RecycleBoxLayout:
            default_size: None, dp(56)
            default_size_hint: 1, None
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'
            spacing: dp(2)
"""

Builder.load_string(kv)


class Test(BoxLayout):
    cycle = NumericProperty(20)

    def populate(self):
        data = [
            {"value": "Entry {}".format(x)}
            for x in range(50)
        ]
        data += data[:self.cycle]
        self.ids.rv.data = data

    def check_scroll_y(self, rv):
        rv = self.ids.rv
        lm = rv.layout_manager

        if rv.scroll_y > 1:
            # cycle_to_bottom
            child = lm.view_opts[-self.cycle]
            x, y = child["pos"]
            w, h = child["size"]
            sy = (y - rv.height + h) / (lm.height - rv.height - lm.spacing[1])
            rv.scroll_y = sy
        elif rv.scroll_y < 0:
            child = lm.view_opts[self.cycle]
            x, y = child["pos"]
            w, h = child["size"]
            sy = (y + h) / (lm.height - rv.height - lm.spacing[1])
            rv.scroll_y = sy


class TestApp(App):
    def build(self):
        self.root = Test()
        self.root.populate()


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