main.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

# Working demonstration of loading and saving data from/to device memory on Android
# in a Python/Kivy application. Tested on Android 6, 10, and 12 (Kivy 2.1.0).
# Credit: github.com/antorix

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.textinput import TextInput
from kivy.uix.label import Label
from kivy.uix.popup import Popup
from kivy.core.window import Window
from android.permissions import request_permissions, Permission
from androidstorage4kivy import SharedStorage, Chooser  # all the job is done via these two modules
import os
import shutil


class KivyLoadSave(App):
    
    def build(self):
        request_permissions([Permission.READ_EXTERNAL_STORAGE,
                             Permission.WRITE_EXTERNAL_STORAGE])  # get the permissions needed

        self.opened_file = None  # file path to load, None initially, changes later on

        self.cache = SharedStorage().get_cache_dir()  #  file cache in the private storage (for cleaning purposes)
        
        self.box = BoxLayout(orientation="vertical")  # create our simple interface
        self.button1 = Button(text="Click here to LOAD any text file\nfrom your device memory",
                              halign="center", size_hint_y=.2)

        # We bind the Chooser class to the 'Load' button. Chooser calls the standard Android
        # browsing dialog and gives us the ability to address the entire file system:
        self.button1.bind(on_release=lambda x: Chooser(self.chooser_callback).choose_content("text/*"))
        
        self.box.add_widget(self.button1)
        self.input = TextInput(hint_text="You will see loaded text here. Or type your own text to save it.",
                               input_type="text", background_color="white", background_normal = "")
        self.box.add_widget(self.input)
        self.button2 = Button(text="Click here to SAVE the text above\nto your device Documents folder",
                              halign="center", size_hint_y=.2,)
        self.button2.bind(on_release=self.save_file)
        self.box.add_widget(self.button2)
        self.popup_size_hint = [.85, .55]
        self.text_size = (
            Window.size[0]*self.popup_size_hint[0] *.9,
            Window.size[1]*self.popup_size_hint[1] *.9
        )

        return self.box

    def chooser_callback(self, uri_list):
        """ Callback handling the chooser """
        
        try:
            for uri in uri_list:               

                # We obtain the file from the Android's "Shared storage", but we can't work with it directly.
                # We need to first copy it to our app's "Private storage." The callback receives the
                # 'android.net.Uri' rather than a usual POSIX-style file path. Calling the 'copy_from_shared'
                # method copies this file to our private storage and returns a normal file path of the
                # copied file in the private storage:
                self.opened_file = SharedStorage().copy_from_shared(uri)

                self.uri = uri  # just to keep the uri for future reference

        except Exception as e:
            pass

    def on_resume(self):
        """ We load our file when the chooser closes and our app resumes from the paused mode """
        
        if self.opened_file is not None:
            with open(self.opened_file, "r") as file:  # we can work with this file in a normal Python way
                self.input.text = str(file.read()).strip()

            Popup(  # informing user about what exactly happened
                title="Info",
                content=Label(
                    text=f"File with the URI:\n\n{self.uri}\n\ncopied to the private storage:\n\n{self.opened_file}\n\nand loaded from there.\n\nFind its content in the text field.",
                    text_size=self.text_size, valign="center"
                ),
                size_hint=self.popup_size_hint
            ).open()

            self.opened_file = None  # reverting file path back to None
            
            if self.cache and os.path.exists(self.cache): shutil.rmtree(self.cache)  # cleaning cache

    def save_file(self, instance):
        """ Save the content of the input field to device's Documents folder """
        
        filename = os.path.join(SharedStorage().get_cache_dir(),
                                "My text from KivyLoadSave.txt")  # forming the path of our new file

        with open(filename, "w") as file:  # creating the file in a normal way, but again in the private storage
            file.write(self.input.text.strip())

        SharedStorage().copy_to_shared(private_file=filename)  # but now we can copy it to the shared storage

        Popup(
            title="Info",
            content=Label(
                text=f"File:\n\n{filename}\n\ncreated and copied to your Documents folder (because Android thinks it's a document), check it there!",
                text_size=self.text_size, valign="center"
            ),
            size_hint=self.popup_size_hint
        ).open()

        # Note that Android copies our file to the Documents folder. It is done automatically. Why?
        # Because we created a .txt file which Android recognizes as a document. If we create an .mp3 file,
        # it will go to the Music folder, etc. Let's try it:

        filename2 = os.path.join(SharedStorage().get_cache_dir(), "My audio track from KivyLoadSave.mp3")
        with open(filename2, "w") as file2:
            file2.write("")
        SharedStorage().copy_to_shared(private_file=filename2)

        # Check your Music folder now. Android also creates a subfolder named after your app.
        # This is the way Google now wants us to work with files and their "Collections".

        if self.cache and os.path.exists(self.cache): shutil.rmtree(self.cache)  # cleaning cache


if __name__ == "__main__":
    KivyLoadSave().run()