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Storage Access Framework

The Storage Access Framework (SAF) is an Android system for browsing and accessing files and directories through a document provider model. Apps use intents like ACTION_OPEN_DOCUMENT and ACTION_OPEN_DOCUMENT_TREE to let the user pick files or a whole folder, and receive a persistable URI instead of a raw file path.

Android developmentAndroid

Storage Access Framework

Also known as: SAF android, document picker

The Storage Access Framework (SAF) is an Android system for browsing and accessing files and directories through a document provider model. Apps use intents like ACTION_OPEN_DOCUMENT and ACTION_OPEN_DOCUMENT_TREE to let the user pick files or a whole folder, and receive a persistable URI instead of a raw file path.

  • SAF returns content:// URIs accessed via ContentResolver, not raw file paths.
  • ACTION_OPEN_DOCUMENT_TREE grants access to an entire user-chosen directory subtree.
  • takePersistableUriPermission keeps a granted URI valid across device reboots.

How SAF works

SAF decouples an app from raw file paths. Instead of touching the filesystem directly, an app fires a system intent such as ACTION_OPEN_DOCUMENT (pick one or more files), ACTION_CREATE_DOCUMENT (create a new file), or ACTION_OPEN_DOCUMENT_TREE (grant access to a directory subtree). Android shows the system document picker UI, backed by registered DocumentsProvider implementations including local storage, Downloads, and cloud providers like Google Drive.

The user's selection returns a content:// URI rather than a `java.io.File` path. The app reads and writes through ContentResolver, calling `openInputStream`, `openFileDescriptor`, or querying the DocumentsContract columns (display name, size, MIME type). For tree access, `DocumentFile.fromTreeUri` exposes child enumeration over the granted subtree.

Persistable permissions and why a cleaner uses SAF

A URI grant is normally tied to the lifetime of the activity. To keep access across reboots, the app calls `ContentResolver.takePersistableUriPermission` with the FLAG_GRANT_READ_URI_PERMISSION (and write) flags captured from the result intent. The granted permissions survive until the user revokes them or the app is uninstalled.

Because scoped storage restricts broad filesystem access, a cleaner app uses ACTION_OPEN_DOCUMENT_TREE to let the user explicitly grant a folder (for example a Downloads or WhatsApp media directory) so it can enumerate, size, and delete files there without the all-files MANAGE_EXTERNAL_STORAGE permission. SAF is the user-consent path for browsing files outside the app's own sandbox.

Related terms

Keep reading the reference.

AndroidScoped storageScoped storage is Android’s privacy model that limits which files an app can see. An app gets free access to its own private folder and to shared media it owns, but needs explicit permission to touch the rest of your files.AndroidAndroid developmentScoped Storage InternalsScoped storage is the Android storage model, introduced in Android 10 and enforced from Android 11, that limits an app's direct filesystem access to its own package directories and the shared media collections. Other apps' files and arbitrary paths are reached only through MediaStore, the Storage Access Framework, or special permissions.AndroidAndroid developmentMANAGE_EXTERNAL_STORAGEMANAGE_EXTERNAL_STORAGE is the Android "All files access" permission that grants an app broad read and write access to most of shared external storage, bypassing scoped storage restrictions. It is a special permission granted only through a system Settings screen, not a runtime dialog, and Google Play strictly gates its use.AndroidAndroid developmentContentResolverContentResolver is the Android client object that talks to content providers. Apps use it to query, insert, update, and delete data behind content:// URIs, including the MediaStore, which is how they list and read photos and videos under scoped storage.Android

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