simple and fast FileChooser

fastfilechooser.py

import typing
from pathlib import Path
from dataclasses import dataclass
from kivy.lang import Builder
from kivy.clock import Clock
from kivy.factory import Factory
from kivy.properties import ObjectProperty, BooleanProperty


@dataclass
class ItemData:
    path: Path
    is_selected: bool = False


Builder.load_string('''
<FastFileChooser>:
    orientation: 'vertical'
    padding: dp(5)
    spacing: dp(5)
    BoxLayout:
        spacing: dp(5)
        size_hint_y: None
        height: self.minimum_height
        Button:
            size_hint: None, None
            size: sp(30), sp(30)
            id: button_move_to_parent
            text: '^'
            on_press: root.current_dir = root.current_dir.parent
        Label:
            text: str(root.current_dir)
            size_hint_y: None
            height: self.texture_size[1]
    RecycleView:
        id: rv
        viewclass: 'FastFileChooserItem'
        RecycleBoxLayout:
            orientation: 'vertical'
            size_hint_y: None
            size_hint_x: 1
            height: self.minimum_height
            default_size_hint: 1, None
            default_size: 0, sp(25)
<FastFileChooserItem>:
    spacing: dp(10)
    canvas:
        Color:
            rgba:
                ((1, 1, 0, .2) if
                (self.data is not None and self.data.is_selected)
                else (0, 0, 0, 0))
        Rectangle:
            pos: self.pos
            size: self.size
    Label:
        size_hint_x: None
        width: sp(20)
        text:'>' if (root.data is not None) and root.data.path.is_dir() else ''
    Label:
        size_hint_x: None
        width: self.texture_size[0]
        text:'' if root.data is None else root.data.path.name
''')


def is_root_path(path:Path) -> bool:
    from kivy.utils import platform
    abs_str = str(path.resolve())
    if platform == 'win':
        if len(abs_str) <= 3 and abs_str[1] == ':':
            return True
    else:
        if abs_str == '/':
            return True
    return False


class FastFileChooser(Factory.BoxLayout):
    multiselect = BooleanProperty(False)
    current_dir = ObjectProperty()

    def on_current_dir(self, __, new_current_dir):
        if not self.ids:
            Clock.schedule_once(lambda dt: self.on_current_dir(__, new_current_dir))
            return
        new_current_dir = new_current_dir.resolve()
        try:
            paths = sorted(
                # (child for child in new_current_dir.iterdir()),
                (child for child in new_current_dir.iterdir() if child.is_dir() or child.is_file()),
                key=lambda p: p.name.lower())
        except PermissionError:
            Factory.Popup(
                size_hint=(.5, .5),
                title='Error',
                content=Factory.Label(
                    text="Access denied!")
            ).open()
            return
        self.current_dir = new_current_dir
        self.ids.button_move_to_parent.disabled = is_root_path(new_current_dir)
        self.ids.rv.data = ({'data': ItemData(path=path) } for index, path in enumerate(paths))

    def get_selection(self) -> typing.Iterable[Path]:
        return (dict_['data'].path for dict_ in self.ids.rv.data if dict_['data'].is_selected)


class FastFileChooserItem(Factory.ButtonBehavior, Factory.BoxLayout):
    data = ObjectProperty(rebind=True)

    @property
    def rv(self):
        return self.parent.parent

    @property
    def fc(self):
        return self.parent.parent.parent

    def on_press(self):
        rv = self.rv
        data = self.data
        path = data.path
        fc = self.fc
        if path.is_file():
            if data.is_selected:
                data.is_selected = False
            else:
                if not fc.multiselect:
                    for dict_ in rv.data:
                        dict_['data'].is_selected = False
                data.is_selected = True
            rv.refresh_from_data()
            self.property('data').dispatch(self)
        elif path.is_dir():
            fc.current_dir = path


def _test():
    from kivy.app import runTouchApp

    ffc = FastFileChooser(multiselect=False, current_dir=Path())
    runTouchApp(ffc)
    for path in ffc.get_selection():
        print(path)

if __name__ == "__main__":
    _test()