問題描述

我有 這個小應(yīng)用程序，我想要重寫它以使用對隱私更友好的最佳實踐，例如存儲訪問框架.

I have this small application and I'd like to rewrite it to use more privacy-friendly best practices, such as the Storage Access Framework.

如何在 Python (Kivy) 中做到這一點?我在網(wǎng)上搜索并沒有找到任何使用 Python 的教程或示例.我對 Java 和 Kotlin 知之甚少.所以，我想閱讀 Python 中的示例.

How to do it in Python (Kivy)? I searched the web and haven't found any tutorial or examples with Python. I know only very little Java and Kotlin at all. So, I would like to read the examples in Python.

我想替換這段代碼:

request_permissions([Permission.WRITE_EXTERNAL_STORAGE,
                             Permission.READ_EXTERNAL_STORAGE])
        try:
            if autoclass('android.os.Build$VERSION').SDK_INT >= 29:
                Context = autoclass('android.content.Context')
                self.working_directory = os.path.join(Context.getExternalFilesDir(None).getAbsolutePath(), "tdg_articles")
                self.data_dir = os.path.join(Context.getExternalFilesDir(None).getAbsolutePath(), "nltk")
            else:
                Environment = autoclass('android.os.Environment')
                self.working_directory = os.path.join(Environment.getExternalStorageDirectory().getAbsolutePath(), "tdg_articles")
                self.data_dir = os.path.join(Environment.getExternalStorageDirectory().getAbsolutePath(), "nltk")
        except:
            self.working_directory = os.path.join(App.get_running_app().user_data_dir, "tdg_articles")
            self.data_dir = os.path.join(App.get_running_app().user_data_dir, "nltk")
        
        if not os.path.exists(self.working_directory):
            os.makedirs(self.working_directory)
        
        if not os.path.exists(self.data_dir):
            os.makedirs(self.data_dir)
        
        os.chdir(self.working_directory)

推薦答案

Scoped Storage帶來兩大變化:

1. 首先，您不再可以通過文件的路徑訪問文件.相反，您需要使用它的 Uri.
2. 其次，如果你想修改一個不是你的應(yīng)用創(chuàng)建的文件，你需要征求用戶的許可.

默認情況下，您有權(quán)訪問其他應(yīng)用無法訪問的特定應(yīng)用文件夾.但是，如果您需要在另一個位置讀取/寫入文件，則必須明確要求它們.范圍存儲類似于訪問數(shù)據(jù)庫.您請求 Android API 執(zhí)行操作，系統(tǒng)會為您執(zhí)行.

By default, you are given access to an app-specific folder that can't be accessed by others apps. However, if you need to read/write the files in another location you have to explicitly ask for them. The scoped storage is similar to accessing a database. You request the Android API to perform the action and the system does it for you.

類似問題:

Github 中有一個類似情況的未解決問題.

There's an open issue in Github that resembles a similar situation.

https://github.com/kivy/buildozer/issues/1304

有用的資源:

我找不到任何官方文檔，但 Robert Flatt 有一個使用范圍存儲的實驗性存儲庫.

I couldn't find any official documentation, but there's an experimental repository by Robert Flatt that uses the scope storage.

https://github.com/Android-for-Python/Storage-Example

他提供了 storage.py 實現(xiàn)用于訪問此應(yīng)用程序公共存儲的數(shù)據(jù)庫的 API 的類.提供的共享存儲操作是 insert()、delete() 和 recieve()，這些在此應(yīng)用的私有存儲和共享存儲之間復(fù)制文件.

He provided the storage.py class that implements an API for database access of this app's public storage. The shared storage operations provided are insert(), delete(), and recieve(), these copy files between this app's private and shared storage.

代碼重構(gòu)建議:

Scoped Storage 不僅限于詢問文件權(quán)限，因此您需要以這種方式遷移所有文件操作.

Scoped Storage isn't limited to asking the file permission only, hence you need to migrate all of your file operations this way.

1. 來自 Android API 29+ WRITE_EXTERNAL_STORAGE"許可是多余的.由于您將通過 MediaStore/SAF 使用存儲，因此您不再需要此權(quán)限.
2. 每當(dāng)您執(zhí)行文件操作時，請檢查 Android 版本，如果低于 29，請繼續(xù)使用現(xiàn)有代碼.否則，使用 storage.py 類讀取/寫入文件.
3. 如果您已經(jīng)將數(shù)據(jù)存儲在應(yīng)用目錄之外，則還需要將它們移動到應(yīng)用目錄內(nèi)的文件夾中.

使用 storage.py 類的示例:

#######################
    #
    # Examples:
    # Where txt_file could be PrivateStorage().getFilesDir() + 'text.txt'
    # and so on.
    # All methods take a required file name, and optional directory parameters.
    #
    #   Insert:
    #   SharedStorage().insert(txt_file, 'Documents')
    #   SharedStorage().insert(txt_file, sub_dir= 'a/b')
    #   SharedStorage().insert(txt_file, 'Downloads')
    #   SharedStorage().insert(jpg_file, 'Pictures')
    #   SharedStorage().insert(mp3_file)
    #   SharedStorage().insert(ogg_file, 'Music')
    #
    #   Retrieve:
    #   path = SharedStorage().retrieve('test.txt')
    #   path = SharedStorage().retrieve('test.txt', 'Documents', 'a/b')
    #
    #   Delete:
    #   SharedStorage().delete('test.mp3', 'Music')
    #
    #   Retrieve from another app's storage (requires READ_EXTERNAL_STORAGE) :
    #   SharedStorage().retrieve('10_28_14.jpg', 'DCIM', '2021_03_12',
    #                            'CameraXF')
    #   SharedStorage().retrieve('10_33_48.mp4', 'DCIM', '2021_03_12',
    #                            'CameraXF')
    #
    #######################

詳細說明在這里.

這篇關(guān)于Python 中的存儲訪問框架的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！