Added in API level 9

StorageManager

---

Kotlin |Java

open class StorageManager

kotlin.Any
↳	android.os.storage.StorageManager

StorageManager is the interface to the systems storage service. The storage manager handles storage-related items such as Opaque Binary Blobs (OBBs).

OBBs contain a filesystem that maybe be encrypted on disk and mounted on-demand from an application. OBBs are a good way of providing large amounts of binary assets without packaging them into APKs as they may be multiple gigabytes in size. However, due to their size, they're most likely stored in a shared storage pool accessible from all programs. The system does not guarantee the security of the OBB file itself: if any program modifies the OBB, there is no guarantee that a read from that OBB will produce the expected output.

Summary

Nested classes
open	StorageVolumeCallback Callback that delivers StorageVolume related events.

Constants
static String	ACTION_CLEAR_APP_CACHE Activity Action: Allows the user to free up space by clearing app external cache directories.
static String	ACTION_MANAGE_STORAGE Activity Action: Allows the user to manage their storage.
static String	EXTRA_REQUESTED_BYTES Extra used to indicate the total size (in bytes) that an application is interested in allocating.
static String	EXTRA_UUID Extra UUID used to indicate the storage volume where an application is interested in allocating or managing disk space.

Public methods
open Unit	allocateBytes(fd: FileDescriptor!, bytes: Long) Allocate the requested number of bytes for your application to use in the given open file.
open Unit	allocateBytes(storageUuid: UUID, bytes: Long) Allocate the requested number of bytes for your application to use on the given storage volume.
open Long	getAllocatableBytes(storageUuid: UUID) Return the maximum number of new bytes that your app can allocate for itself on the given storage volume.
open Long	getCacheQuotaBytes(storageUuid: UUID) Return quota size in bytes for all cached data belonging to the calling app on the given storage volume.
open Long	getCacheSizeBytes(storageUuid: UUID) Return total size in bytes of all cached data belonging to the calling app on the given storage volume.
open PendingIntent?	getManageSpaceActivityIntent(packageName: String, requestCode: Int) Returns a PendingIntent that can be used by Apps with android.Manifest.permission#MANAGE_EXTERNAL_STORAGE permission to launch the manageSpaceActivity for any App that implements it, irrespective of its exported status.
open String!	getMountedObbPath(rawPath: String!) Check the mounted path of an Opaque Binary Blob (OBB) file.
open StorageVolume	getPrimaryStorageVolume() Return the primary shared/external storage volume available to the current user.
open MutableList<StorageVolume!>	getRecentStorageVolumes() Return the list of shared/external storage volumes both currently and recently available to the calling user.
open StorageVolume	getStorageVolume(uri: Uri) Return the StorageVolume that contains the given MediaStore item.
open StorageVolume?	getStorageVolume(file: File) Return the StorageVolume that contains the given file, or null if none.
open MutableList<StorageVolume!>	getStorageVolumes() Return the list of shared/external storage volumes currently available to the calling user.
open MutableList<StorageVolume!>	getStorageVolumesIncludingSharedProfiles() Return the list of shared/external storage volumes currently available to the calling user and the user it shares media with.
open UUID	getUuidForPath(path: File) Return a UUID identifying the storage volume that hosts the given filesystem path.
open Boolean	isAllocationSupported(fd: FileDescriptor) Test if the given file descriptor supports allocation of disk space using allocateBytes(java.io.FileDescriptor,long).
open Boolean	isCacheBehaviorGroup(path: File!) Read the current value set by setCacheBehaviorGroup(java.io.File,boolean).
open Boolean	isCacheBehaviorTombstone(path: File!) Read the current value set by setCacheBehaviorTombstone(java.io.File,boolean).
open Boolean	isCheckpointSupported() Check whether the device supports filesystem checkpoint.
open Boolean	isEncrypted(file: File!) Return if data stored at or under the given path will be encrypted while at rest.
open Boolean	isObbMounted(rawPath: String!) Check whether an Opaque Binary Blob (OBB) is mounted or not.
open Boolean	mountObb(rawPath: String!, key: String!, listener: OnObbStateChangeListener!) Mount an Opaque Binary Blob (OBB) file.
open ParcelFileDescriptor	openProxyFileDescriptor(mode: Int, callback: ProxyFileDescriptorCallback!, handler: Handler!) Opens a seekable ParcelFileDescriptor that proxies all low-level I/O requests back to the given ProxyFileDescriptorCallback.
open Unit	registerStorageVolumeCallback(executor: Executor, callback: StorageManager.StorageVolumeCallback) Registers the given callback to listen for StorageVolume changes.
open Unit	setCacheBehaviorGroup(path: File!, group: Boolean) Enable or disable special cache behavior that treats this directory and its contents as an entire group.
open Unit	setCacheBehaviorTombstone(path: File!, tombstone: Boolean) Enable or disable special cache behavior that leaves deleted cache files intact as tombstones.
open Boolean	unmountObb(rawPath: String!, force: Boolean, listener: OnObbStateChangeListener!) Unmount an Opaque Binary Blob (OBB) file asynchronously.
open Unit	unregisterStorageVolumeCallback(callback: StorageManager.StorageVolumeCallback) Unregisters the given callback from listening for StorageVolume changes.

Properties
static UUID!	UUID_DEFAULT UUID representing the default internal storage of this device which provides Environment.getDataDirectory().

Constants

ACTION_CLEAR_APP_CACHE

Added in API level 30

static val ACTION_CLEAR_APP_CACHE: String

Activity Action: Allows the user to free up space by clearing app external cache directories. The intent doesn't automatically clear cache, but shows a dialog and lets the user decide.

This intent should be launched using Activity.startActivityForResult(Intent, int) so that the user knows which app is requesting to clear cache. The returned result will be: Activity.RESULT_OK if the activity was launched and all cache was cleared, OsConstants.EIO if an error occurred while clearing the cache or Activity.RESULT_CANCELED otherwise.
Requires android.Manifest.permission#MANAGE_EXTERNAL_STORAGE

Value: "android.os.storage.action.CLEAR_APP_CACHE"

ACTION_MANAGE_STORAGE

Added in API level 25

static val ACTION_MANAGE_STORAGE: String

Activity Action: Allows the user to manage their storage. This activity provides the ability to free up space on the device by deleting data such as apps.

If the sending application has a specific storage device or allocation size in mind, they can optionally define EXTRA_UUID or EXTRA_REQUESTED_BYTES, respectively.

This intent should be launched using Activity.startActivityForResult(Intent, int) so that the user knows which app is requesting the storage space. The returned result will be Activity.RESULT_OK if the requested space was made available, or Activity.RESULT_CANCELED otherwise.

Value: "android.os.storage.action.MANAGE_STORAGE"

EXTRA_REQUESTED_BYTES

Added in API level 26

static val EXTRA_REQUESTED_BYTES: String

Extra used to indicate the total size (in bytes) that an application is interested in allocating.

When defined, the management UI will help guide the user to free up enough disk space to reach this requested value.

Value: "android.os.storage.extra.REQUESTED_BYTES"

See Also

• #ACTION_MANAGE_STORAGE

EXTRA_UUID

Added in API level 26

static val EXTRA_UUID: String

Extra UUID used to indicate the storage volume where an application is interested in allocating or managing disk space.

Value: "android.os.storage.extra.UUID"

See Also

• #ACTION_MANAGE_STORAGE
• #UUID_DEFAULT
• #getUuidForPath(File)
• android.content.Intent#putExtra(String, java.io.Serializable)

Public methods

allocateBytes

Added in API level 26

open fun allocateBytes(
    fd: FileDescriptor!, 
    bytes: Long
): Unit

Allocate the requested number of bytes for your application to use in the given open file. This will cause the system to delete any cached files necessary to satisfy your request.

Attempts to allocate disk space beyond the value returned by getAllocatableBytes(java.util.UUID) will fail.

This method guarantees that bytes have been allocated to the opened file, otherwise it will throw if fast allocation is not possible. Fast allocation is typically only supported in private app data directories, and on shared/external storage devices which are emulated.

If you're progressively allocating an unbounded amount of storage space (such as when recording a video) you should avoid calling this method more than once every 60 seconds.
This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
fd	FileDescriptor!: the open file that you'd like to allocate disk space for.
bytes	Long: the number of bytes to allocate. This is the desired final size of the open file. If the open file is smaller than this requested size, it will be extended without modifying any existing contents. If the open file is larger than this requested size, it will be truncated. Value is a non-negative number of bytes.

Exceptions
java.io.IOException	when the storage device isn't present, or when it doesn't support allocating space, or if the device had trouble allocating the requested space.

See Also

• #isAllocationSupported(FileDescriptor)
• android.os.Environment#isExternalStorageEmulated(File)

allocateBytes

Added in API level 26

open fun allocateBytes(
    storageUuid: UUID, 
    bytes: Long
): Unit

Allocate the requested number of bytes for your application to use on the given storage volume. This will cause the system to delete any cached files necessary to satisfy your request.

Attempts to allocate disk space beyond the value returned by getAllocatableBytes(java.util.UUID) will fail.

Since multiple apps can be running simultaneously, this method may be subject to race conditions. If possible, consider using allocateBytes(java.io.FileDescriptor,long) which will guarantee that bytes are allocated to an opened file.

If you're progressively allocating an unbounded amount of storage space (such as when recording a video) you should avoid calling this method more than once every 60 seconds.
This method may take several seconds to complete, so it should only be called from a worker thread.

Parameters
storageUuid	UUID: the UUID of the storage volume where you'd like to allocate disk space. The UUID for a specific path can be obtained using getUuidForPath(java.io.File). This value cannot be null.
bytes	Long: the number of bytes to allocate. Value is a non-negative number of bytes.

Exceptions
java.io.IOException	when the storage device isn't present, or when it doesn't support allocating space, or if the device had trouble allocating the requested space.

See Also

• #getAllocatableBytes(UUID)

getAllocatableBytes

Added in API level 26

open fun getAllocatableBytes(storageUuid: UUID): Long

Return the maximum number of new bytes that your app can allocate for itself on the given storage volume. This value is typically larger than File.getUsableSpace(), since the system may be willing to delete cached files to satisfy an allocation request. You can then allocate space for yourself using allocateBytes(java.util.UUID,long) or allocateBytes(java.io.FileDescriptor,long).

This method is best used as a pre-flight check, such as deciding if there is enough space to store an entire music album before you allocate space for each audio file in the album. Attempts to allocate disk space beyond the returned value will fail.

If the returned value is not large enough for the data you'd like to persist, you can launch ACTION_MANAGE_STORAGE with the EXTRA_UUID and EXTRA_REQUESTED_BYTES options to help involve the user in freeing up disk space.

If you're progressively allocating an unbounded amount of storage space (such as when recording a video) you should avoid calling this method more than once every 30 seconds.

Note: if your app uses the android:sharedUserId manifest feature, then allocatable space for all packages in your shared UID is tracked together as a single unit.

This method may take several seconds to complete, so it should only be called from a worker thread.
Value is a non-negative number of bytes.

Parameters
storageUuid	UUID: the UUID of the storage volume where you're considering allocating disk space, since allocatable space can vary widely depending on the underlying storage device. The UUID for a specific path can be obtained using getUuidForPath(java.io.File). This value cannot be null.

Return
Long	the maximum number of new bytes that the calling app can allocate using allocateBytes(java.util.UUID,long) or allocateBytes(java.io.FileDescriptor,long). Value is a non-negative number of bytes.

Exceptions
java.io.IOException	when the storage device isn't present, or when it doesn't support allocating space.

getCacheQuotaBytes

Added in API level 26

open fun getCacheQuotaBytes(storageUuid: UUID): Long

Return quota size in bytes for all cached data belonging to the calling app on the given storage volume.

If your app goes above this quota, your cached files will be some of the first to be deleted when additional disk space is needed. Conversely, if your app stays under this quota, your cached files will be some of the last to be deleted when additional disk space is needed.

This quota will change over time depending on how frequently the user interacts with your app, and depending on how much system-wide disk space is used.

Note: if your app uses the android:sharedUserId manifest feature, then cached data for all packages in your shared UID is tracked together as a single unit.

This method may take several seconds to complete, so it should only be called from a worker thread.
Value is a non-negative number of bytes.

Parameters
storageUuid	UUID: the UUID of the storage volume that you're interested in. The UUID for a specific path can be obtained using getUuidForPath(java.io.File). This value cannot be null.

Return
Long	Value is a non-negative number of bytes.

Exceptions
java.io.IOException	when the storage device isn't present, or when it doesn't support cache quotas.

See Also

• #getCacheSizeBytes(UUID)

getCacheSizeBytes

Added in API level 26

open fun getCacheSizeBytes(storageUuid: UUID): Long

Return total size in bytes of all cached data belonging to the calling app on the given storage volume.

Cached data tracked by this method always includes Context.getCacheDir() and Context.getCodeCacheDir(), and it also includes Context.getExternalCacheDir() if the primary shared/external storage is hosted on the same storage device as your private data.

Note: if your app uses the android:sharedUserId manifest feature, then cached data for all packages in your shared UID is tracked together as a single unit.

This method may take several seconds to complete, so it should only be called from a worker thread.
Value is a non-negative number of bytes.

Parameters
storageUuid	UUID: the UUID of the storage volume that you're interested in. The UUID for a specific path can be obtained using getUuidForPath(java.io.File). This value cannot be null.

Return
Long	Value is a non-negative number of bytes.

Exceptions
java.io.IOException	when the storage device isn't present, or when it doesn't support cache quotas.

See Also

• #getCacheQuotaBytes(UUID)

getManageSpaceActivityIntent

Added in API level 31

open fun getManageSpaceActivityIntent(
    packageName: String, 
    requestCode: Int
): PendingIntent?

Returns a PendingIntent that can be used by Apps with android.Manifest.permission#MANAGE_EXTERNAL_STORAGE permission to launch the manageSpaceActivity for any App that implements it, irrespective of its exported status.

Caller has the responsibility of supplying a valid packageName which has manageSpaceActivity implemented.
Requires android.Manifest.permission#MANAGE_EXTERNAL_STORAGE

Parameters
packageName	String: package name for the App for which manageSpaceActivity is to be launched This value cannot be null.
requestCode	Int: for launching the activity

Return
PendingIntent?	PendingIntent to launch the manageSpaceActivity if successful, null if the packageName doesn't have a manageSpaceActivity.

Exceptions
java.lang.IllegalArgumentException	an invalid packageName is supplied.

getMountedObbPath

Added in API level 9

open fun getMountedObbPath(rawPath: String!): String!

Check the mounted path of an Opaque Binary Blob (OBB) file. This will give you the path to where you can obtain access to the internals of the OBB.

Parameters
rawPath	String!: path to OBB image

Return
String!	absolute path to mounted OBB image data or null if not mounted or exception encountered trying to read status

getPrimaryStorageVolume

Added in API level 24

open fun getPrimaryStorageVolume(): StorageVolume

Return the primary shared/external storage volume available to the current user. This volume is the same storage device returned by Environment.getExternalStorageDirectory() and Context.getExternalFilesDir(String).

Return
StorageVolume	This value cannot be null.

getRecentStorageVolumes

Added in API level 30

open fun getRecentStorageVolumes(): MutableList<StorageVolume!>

Return the list of shared/external storage volumes both currently and recently available to the calling user.

Recently available storage volumes are likely to reappear in the future, so apps are encouraged to preserve any indexed metadata related to these volumes to optimize user experiences.

Return
MutableList<StorageVolume!>	This value cannot be null.

getStorageVolume

Added in API level 29

open fun getStorageVolume(uri: Uri): StorageVolume

Return the StorageVolume that contains the given MediaStore item.

Parameters
uri	Uri: This value cannot be null.

Return
StorageVolume	This value cannot be null.

getStorageVolume

Added in API level 24

open fun getStorageVolume(file: File): StorageVolume?

Return the StorageVolume that contains the given file, or null if none.

Parameters
file	File: This value cannot be null.

getStorageVolumes

Added in API level 24

open fun getStorageVolumes(): MutableList<StorageVolume!>

Return the list of shared/external storage volumes currently available to the calling user.

These storage volumes are actively attached to the device, but may be in any mount state, as returned by StorageVolume.getState(). Returns both the primary shared storage device and any attached external volumes, including SD cards and USB drives.

Return
MutableList<StorageVolume!>	This value cannot be null.

getStorageVolumesIncludingSharedProfiles

Added in API level 33

open fun getStorageVolumesIncludingSharedProfiles(): MutableList<StorageVolume!>

Return the list of shared/external storage volumes currently available to the calling user and the user it shares media with. Please refer to multi-user support for more details.

This is similar to StorageManager.getStorageVolumes() except that the result also includes the volumes belonging to any user it shares media with
Requires android.Manifest.permission#MANAGE_EXTERNAL_STORAGE

Return
MutableList<StorageVolume!>	This value cannot be null.

getUuidForPath

Added in API level 26

open fun getUuidForPath(path: File): UUID

Return a UUID identifying the storage volume that hosts the given filesystem path.

If this path is hosted by the default internal storage of the device at Environment.getDataDirectory(), the returned value will be UUID_DEFAULT.

Parameters
path	File: This value cannot be null.

Return
UUID	This value cannot be null.

Exceptions
java.io.IOException	when the storage device hosting the given path isn't present, or when it doesn't have a valid UUID.

isAllocationSupported

Added in API level 27

open fun isAllocationSupported(fd: FileDescriptor): Boolean

Test if the given file descriptor supports allocation of disk space using allocateBytes(java.io.FileDescriptor,long).

Parameters
fd	FileDescriptor: This value cannot be null.

isCacheBehaviorGroup

Added in API level 26

open fun isCacheBehaviorGroup(path: File!): Boolean

Read the current value set by setCacheBehaviorGroup(java.io.File,boolean).

isCacheBehaviorTombstone

Added in API level 26

open fun isCacheBehaviorTombstone(path: File!): Boolean

Read the current value set by setCacheBehaviorTombstone(java.io.File,boolean).

isCheckpointSupported

Added in API level 30

open fun isCheckpointSupported(): Boolean

Check whether the device supports filesystem checkpoint.

Return
Boolean	true if the device supports filesystem checkpoint, false otherwise.

isEncrypted

Added in API level 24

open fun isEncrypted(file: File!): Boolean

Return if data stored at or under the given path will be encrypted while at rest. This can help apps avoid the overhead of double-encrypting data.

isObbMounted

Added in API level 9

open fun isObbMounted(rawPath: String!): Boolean

Check whether an Opaque Binary Blob (OBB) is mounted or not.

Parameters
rawPath	String!: path to OBB image

Return
Boolean	true if OBB is mounted; false if not mounted or on error

mountObb

Added in API level 9

open fun mountObb(
    rawPath: String!, 
    key: String!, 
    listener: OnObbStateChangeListener!
): Boolean

Mount an Opaque Binary Blob (OBB) file.

The OBB will remain mounted for as long as the StorageManager reference is held by the application. As soon as this reference is lost, the OBBs in use will be unmounted. The OnObbStateChangeListener registered with this call will receive the success or failure of this operation.

Note: you can only mount OBB files for which the OBB tag on the file matches a package ID that is owned by the calling program's UID. That is, shared UID applications can attempt to mount any other application's OBB that shares its UID.

Parameters
rawPath	String!: the path to the OBB file
key	String!: must be null. Previously, some Android device implementations accepted a non-null key to mount an encrypted OBB file. However, this never worked reliably and is no longer supported.
listener	OnObbStateChangeListener!: will receive the success or failure of the operation

Return
Boolean	whether the mount call was successfully queued or not

openProxyFileDescriptor

Added in API level 26

open fun openProxyFileDescriptor(
    mode: Int, 
    callback: ProxyFileDescriptorCallback!, 
    handler: Handler!
): ParcelFileDescriptor

Opens a seekable ParcelFileDescriptor that proxies all low-level I/O requests back to the given ProxyFileDescriptorCallback.

This can be useful when you want to provide quick access to a large file that isn't backed by a real file on disk, such as a file on a network share, cloud storage service, etc. As an example, you could respond to a ContentResolver.openFileDescriptor(android.net.Uri, String) request by returning a ParcelFileDescriptor created with this method, and then stream the content on-demand as requested.

Another useful example might be where you have an encrypted file that you're willing to decrypt on-demand, but where you want to avoid persisting the cleartext version.

Parameters
mode	Int: The desired access mode, must be one of ParcelFileDescriptor.MODE_READ_ONLY, ParcelFileDescriptor.MODE_WRITE_ONLY, or ParcelFileDescriptor.MODE_READ_WRITE
callback	ProxyFileDescriptorCallback!: Callback to process file operation requests issued on returned file descriptor.
handler	Handler!: Handler that invokes callback methods.

Return
ParcelFileDescriptor	Seekable ParcelFileDescriptor. This value cannot be null.

Exceptions
java.io.IOException

registerStorageVolumeCallback

Added in API level 30

open fun registerStorageVolumeCallback(
    executor: Executor, 
    callback: StorageManager.StorageVolumeCallback
): Unit

Registers the given callback to listen for StorageVolume changes.

For example, this can be used to detect when a volume changes to the Environment.MEDIA_MOUNTED or Environment.MEDIA_UNMOUNTED states.

Parameters
executor	Executor: Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). Otherwise, provide an Executor that dispatches to an appropriate thread. This value cannot be null.
callback	StorageManager.StorageVolumeCallback: This value cannot be null.

See Also

• android.os.storage.StorageManager#unregisterStorageVolumeCallback

setCacheBehaviorGroup

Added in API level 26

open fun setCacheBehaviorGroup(
    path: File!, 
    group: Boolean
): Unit

Enable or disable special cache behavior that treats this directory and its contents as an entire group.

When enabled and this directory is considered for automatic deletion by the OS, all contained files will either be deleted together, or not at all. This is useful when you have a directory that contains several related metadata files that depend on each other, such as movie file and a subtitle file.

When enabled, the newest File.lastModified() value of any contained files is considered the modified time of the entire directory.

This behavior can only be set on a directory, and it applies recursively to all contained files and directories.

setCacheBehaviorTombstone

Added in API level 26

open fun setCacheBehaviorTombstone(
    path: File!, 
    tombstone: Boolean
): Unit

Enable or disable special cache behavior that leaves deleted cache files intact as tombstones.

When enabled and a file contained in this directory is automatically deleted by the OS, the file will be truncated to have a length of 0 bytes instead of being fully deleted. This is useful if you need to distinguish between a file that was deleted versus one that never existed.

This behavior can only be set on a directory, and it applies recursively to all contained files and directories.

Note: this behavior is ignored completely if the user explicitly requests that all cached data be cleared.

unmountObb

Added in API level 9

open fun unmountObb(
    rawPath: String!, 
    force: Boolean, 
    listener: OnObbStateChangeListener!
): Boolean

Unmount an Opaque Binary Blob (OBB) file asynchronously. If the force flag is true, it will kill any application needed to unmount the given OBB (even the calling application).

The OnObbStateChangeListener registered with this call will receive the success or failure of this operation.

Note: you can only mount OBB files for which the OBB tag on the file matches a package ID that is owned by the calling program's UID. That is, shared UID applications can obtain access to any other application's OBB that shares its UID.

Parameters
rawPath	String!: path to the OBB file
force	Boolean: whether to kill any programs using this in order to unmount it
listener	OnObbStateChangeListener!: will receive the success or failure of the operation

Return
Boolean	whether the unmount call was successfully queued or not

unregisterStorageVolumeCallback

Added in API level 30

open fun unregisterStorageVolumeCallback(callback: StorageManager.StorageVolumeCallback): Unit

Unregisters the given callback from listening for StorageVolume changes.

Parameters
callback	StorageManager.StorageVolumeCallback: This value cannot be null.

See Also

• android.os.storage.StorageManager#registerStorageVolumeCallback

Properties

UUID_DEFAULT

Added in API level 26

static val UUID_DEFAULT: UUID!

UUID representing the default internal storage of this device which provides Environment.getDataDirectory().

This value is constant across all devices and it will never change, and thus it cannot be used to uniquely identify a particular physical device.

See Also

• #getUuidForPath(File)
• android.content.pm.ApplicationInfo#storageUuid