Application Data & Files
Android uses a file system that's similar to disk-based file systems on other platforms. The system provides several options for saving app data:
App-specific storage - internal storage to saving sensitive information that other apps should not be able to access.
Shared storage - storage for files that the app shares with other apps, including media, documents, and other files.
Preferences - storage for private, primitive data in key-value pairs.
Databases - storage for structured data in a private database using the Room persistence library.
| Type of content | Access method | Permissions needed | |
|---|---|---|---|
App-specific files | From internal storage, getFilesDir() and getCacheDir() From external storage, getExternalFilesDir() and getExternalCacheDir() | Never needed for internal storage Not needed for external storage when your app is used on devices that run Android 4.4 (API level 19) or higher | |
Shareable media files (images, audio files, videos) | MediaStore API | READ_EXTERNAL_STORAGE when accessing other apps' files on Android 11 (API level 30) or higher READ_EXTERNAL_STORAGE or WRITE_EXTERNAL_STORAGE when accessing other apps' files on Android 10 (API level 29) Permissions are required for all files on Android 9 (API level 28) or lower | |
Other types of shareable content, including downloaded files | Storage Access Framework | None | |
Key-value pairs | Jetpack Preferences library | None | |
Database | Structured data | Room persistence library | None |
References
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