Added in API level 21

Session

open class Session : Closeable
kotlin.Any
   ↳ android.content.pm.PackageInstaller.Session

An installation that is being actively staged. For an install to succeed, all existing and new packages must have identical package names, version codes, and signing certificates.

A session may contain any number of split packages. If the application does not yet exist, this session must include a base package.

If an APK included in this session is already defined by the existing installation (for example, the same split name), the APK in this session will replace the existing APK.

In such a case that multiple packages need to be committed simultaneously, multiple sessions can be referenced by a single multi-package session. This session is created with no package name and calling SessionParams#setMultiPackage(). The individual session IDs can be added with addChildSessionId(int) and commit of the multi-package session will result in all child sessions being committed atomically.

Summary

Public methods
open Unit

Completely abandon this session, destroying all staged data and rendering it invalid.
open Unit
addChildSessionId(sessionId: Int)

Adds a session ID to the set of sessions that will be committed atomically when this session is committed.
open Unit

Release this session object.
open Unit
commit(statusReceiver: IntentSender)

Attempt to commit everything staged in this session.
open Unit

Ensure that any outstanding data for given stream has been committed to disk.
open PersistableBundle

open IntArray

open Array<String!>

Return all APK names contained in this session.
open Int

open Boolean

open Boolean

open Boolean

open Boolean

open InputStream

Open a stream to read an APK file from the session.
open OutputStream
openWrite(name: String, offsetBytes: Long, lengthBytes: Long)

Open a stream to write an APK file into the session.
open Unit

Removes a session ID from the set of sessions that will be committed atomically when this session is committed.
open Unit
removeSplit(splitName: String)

Removes a split.
open Unit
requestChecksums(name: String, required: Int, trustedInstallers: MutableList<Certificate!>, executor: Executor, onChecksumsReadyListener: PackageManager.OnChecksumsReadyListener)

Requests checksums for the APK file in session.
open Unit

Attempt to request the approval before committing this session.
open Unit

Optionally set the app metadata.
open Unit
setChecksums(name: String, checksums: MutableList<Checksum!>, signature: ByteArray?)

Sets installer-provided checksums for the APK file in session.
open Unit

Set current progress of staging this session.
open Unit
transfer(packageName: String)

Transfer the session to a new owner.

Public methods

abandon

Added in API level 21
open fun abandon(): Unit

Completely abandon this session, destroying all staged data and rendering it invalid. Abandoned sessions will be reported to SessionCallback listeners as failures. This is equivalent to abandonSession(int).

If the parent is abandoned, all children will also be abandoned. Any written data would be destroyed and the created Session information will be discarded.

addChildSessionId

Added in API level 29
open fun addChildSessionId(sessionId: Int): Unit

Adds a session ID to the set of sessions that will be committed atomically when this session is committed.

If the parent is staged or has rollback enabled, all children must have the same properties.

If the parent is abandoned, all children will also be abandoned.

Parameters
sessionId Int: the session ID to add to this multi-package session.

close

Added in API level 21
open fun close(): Unit

Release this session object. You can open the session again if it hasn't been finalized.

Exceptions
java.lang.Exception if this resource cannot be closed
java.io.IOException if an I/O error occurs

commit

Added in API level 21
open fun commit(statusReceiver: IntentSender): Unit

Attempt to commit everything staged in this session. This may require user intervention, and so it may not happen immediately. The final result of the commit will be reported through the given callback.

Once this method is called, the session is sealed and no additional mutations may be performed on the session. In case of device reboot or data loader transient failure before the session has been finalized, you may commit the session again.

If the installer is the device owner, the affiliated profile owner, or has received user pre-approval of this session, there will be no user intervention.

Parameters
statusReceiver IntentSender: Called when the state of the session changes. Intents sent to this receiver contain EXTRA_STATUS. Refer to the individual status codes on how to handle them. This value cannot be null.
Exceptions
java.lang.SecurityException if streams opened through openWrite(java.lang.String,long,long) are still open.
java.lang.IllegalArgumentException if the statusReceiver from an immutable android.app.PendingIntent when caller has a target SDK of API version 35 or above.

fsync

Added in API level 21
open fun fsync(out: OutputStream): Unit

Ensure that any outstanding data for given stream has been committed to disk. This is only valid for streams returned from openWrite(java.lang.String,long,long).

Parameters
out OutputStream: This value cannot be null.

getAppMetadata

Added in API level 34
open fun getAppMetadata(): PersistableBundle
Return
PersistableBundle A PersistableBundle containing the app metadata set with Session#setAppMetadata(PersistableBundle). In the case where this data does not exist, an empty PersistableBundle is returned. This value cannot be null.

getChildSessionIds

Added in API level 29
open fun getChildSessionIds(): IntArray
Return
IntArray the set of session IDs that will be committed atomically when this session is committed if this is a multi-package session or null if none exist.

getNames

Added in API level 21
open fun getNames(): Array<String!>

Return all APK names contained in this session.

This returns all names which have been previously written through openWrite(java.lang.String,long,long) as part of this session.

Return
Array<String!> This value cannot be null.
Exceptions
java.lang.SecurityException if called after the session has been abandoned.

getParentSessionId

Added in API level 29
open fun getParentSessionId(): Int
Return
Int the session ID of the multi-package session that this belongs to or SessionInfo#INVALID_ID if it does not belong to a multi-package session.

isApplicationEnabledSettingPersistent

Added in API level 34
open fun isApplicationEnabledSettingPersistent(): Boolean
Return
Boolean true if this session will keep the existing application enabled setting after installation.

isMultiPackage

Added in API level 29
open fun isMultiPackage(): Boolean
Return
Boolean true if this session will commit more than one package when it is committed.

isRequestUpdateOwnership

Added in API level 34
open fun isRequestUpdateOwnership(): Boolean
Return
Boolean true if the installer requested the update ownership enforcement for the packages in this session.

isStaged

Added in API level 29
open fun isStaged(): Boolean
Return
Boolean true if this session will be staged and applied at next reboot.

openRead

Added in API level 21
open fun openRead(name: String): InputStream

Open a stream to read an APK file from the session.

This is only valid for names which have been previously written through openWrite(java.lang.String,long,long) as part of this session. For example, this stream may be used to calculate a MessageDigest of a written APK before committing.

Parameters
name String: This value cannot be null.
Return
InputStream This value cannot be null.
Exceptions
java.lang.SecurityException if called after the session has been committed or abandoned.

openWrite

Added in API level 21
open fun openWrite(
    name: String, 
    offsetBytes: Long, 
    lengthBytes: Long
): OutputStream

Open a stream to write an APK file into the session.

The returned stream will start writing data at the requested offset in the underlying file, which can be used to resume a partially written file. If a valid file length is specified, the system will preallocate the underlying disk space to optimize placement on disk. It's strongly recommended to provide a valid file length when known.

You can write data into the returned stream, optionally call fsync(java.io.OutputStream) as needed to ensure bytes have been persisted to disk, and then close when finished. All streams must be closed before calling commit(android.content.IntentSender).

Parameters
name String: arbitrary, unique name of your choosing to identify the APK being written. You can open a file again for additional writes (such as after a reboot) by using the same name. This name is only meaningful within the context of a single install session. This value cannot be null.
offsetBytes Long: offset into the file to begin writing at, or 0 to start at the beginning of the file.
lengthBytes Long: total size of the file being written, used to preallocate the underlying disk space, or -1 if unknown. The system may clear various caches as needed to allocate this space.
Return
OutputStream This value cannot be null.
Exceptions
java.io.IOException if trouble opening the file for writing, such as lack of disk space or unavailable media.
java.lang.SecurityException if called after the session has been sealed or abandoned

removeChildSessionId

Added in API level 29
open fun removeChildSessionId(sessionId: Int): Unit

Removes a session ID from the set of sessions that will be committed atomically when this session is committed.

Parameters
sessionId Int: the session ID to remove from this multi-package session.

removeSplit

Added in API level 24
open fun removeSplit(splitName: String): Unit

Removes a split.

Split removals occur prior to adding new APKs. If upgrading a feature split, it is not expected nor desirable to remove the split prior to upgrading.

When split removal is bundled with new APKs, the packageName must be identical.

Parameters
splitName String: This value cannot be null.

requestChecksums

Added in API level 33
open fun requestChecksums(
    name: String, 
    required: Int, 
    trustedInstallers: MutableList<Certificate!>, 
    executor: Executor, 
    onChecksumsReadyListener: PackageManager.OnChecksumsReadyListener
): Unit

Requests checksums for the APK file in session.

A possible use case is replying to Intent#ACTION_PACKAGE_NEEDS_VERIFICATION broadcast. The checksums will be returned asynchronously via onChecksumsReadyListener.

By default returns all readily available checksums:

  • enforced by platform,
  • enforced by the installer.
If the caller needs a specific checksum type, they can specify it as required.

Caution: Android can not verify installer-provided checksums. Make sure you specify trusted installers.

Parameters
name String: previously written as part of this session. openWrite This value cannot be null.
required Int: to explicitly request the checksum types. Will incur significant CPU/memory/disk usage. Value is either 0 or a combination of android.content.pm.Checksum#TYPE_WHOLE_MERKLE_ROOT_4K_SHA256, android.content.pm.Checksum#TYPE_WHOLE_MD5, android.content.pm.Checksum#TYPE_WHOLE_SHA1, android.content.pm.Checksum#TYPE_WHOLE_SHA256, android.content.pm.Checksum#TYPE_WHOLE_SHA512, android.content.pm.Checksum#TYPE_PARTIAL_MERKLE_ROOT_1M_SHA256, and android.content.pm.Checksum#TYPE_PARTIAL_MERKLE_ROOT_1M_SHA512
trustedInstallers MutableList<Certificate!>: for checksums enforced by installer, which installers are to be trusted. PackageManager#TRUST_ALL will return checksums from any installer, PackageManager#TRUST_NONE disables optimized installer-enforced checksums, otherwise the list has to be a non-empty list of certificates. This value cannot be null.
executor Executor: the Executor on which to invoke the callback This value cannot be null. 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.
onChecksumsReadyListener PackageManager.OnChecksumsReadyListener: called once when the results are available. This value cannot be null.
Exceptions
java.security.cert.CertificateEncodingException if an encoding error occurs for trustedInstallers.
java.io.FileNotFoundException if the file does not exist.
java.lang.IllegalArgumentException if the list of trusted installer certificates is empty.

requestUserPreapproval

Added in API level 34
open fun requestUserPreapproval(
    details: PackageInstaller.PreapprovalDetails, 
    statusReceiver: IntentSender
): Unit

Attempt to request the approval before committing this session. For installers that have been granted the REQUEST_INSTALL_PACKAGES permission, they can request the approval from users before Session#commit(IntentSender) is called. This may require user intervention as well. When user intervention is required, installers will receive a STATUS_PENDING_USER_ACTION callback, and STATUS_SUCCESS otherwise. In case that requesting user pre-approval is not available, installers will receive STATUS_FAILURE_BLOCKED instead. Note that if the users decline the request, this session will be abandoned. If user intervention is required but never resolved, or requesting user pre-approval is not available, you may still call Session#commit(IntentSender) as the typical installation.

Parameters
details PackageInstaller.PreapprovalDetails: the adequate context to this session for requesting the approval from users prior to commit. This value cannot be null.
statusReceiver IntentSender: called when the state of the session changes. Intents sent to this receiver contain EXTRA_STATUS and the EXTRA_PRE_APPROVAL would be true. Refer to the individual status codes on how to handle them. This value cannot be null.
Exceptions
java.lang.IllegalArgumentException if IntentSender is null.
java.lang.IllegalStateException if called again after this method has been called on this session.
java.lang.SecurityException if called after the session has been committed or abandoned.

setAppMetadata

Added in API level 34
open fun setAppMetadata(data: PersistableBundle?): Unit

Optionally set the app metadata. The size of this data cannot exceed the maximum allowed. Any existing data from the previous install will not be retained even if no data is set for the current install session. Setting data to null or an empty PersistableBundle will remove any metadata that has previously been set in the same session.

Parameters
data PersistableBundle?: a PersistableBundle containing the app metadata. This value may be null.
Exceptions
java.io.IOException if writing the data fails.

setChecksums

Added in API level 31
Deprecated in API level 31
open fun setChecksums(
    name: String, 
    checksums: MutableList<Checksum!>, 
    signature: ByteArray?
): Unit

Deprecated: do not use installer-provided checksums, use platform-enforced checksums e.g. Checksum#TYPE_WHOLE_MERKLE_ROOT_4K_SHA256 in PackageManager#requestChecksums.

Sets installer-provided checksums for the APK file in session.

Parameters
name String: previously written as part of this session. openWrite This value cannot be null.
checksums MutableList<Checksum!>: installer intends to make available via PackageManager#requestChecksums or requestChecksums. This value cannot be null.
signature ByteArray?: DER PKCS#7 detached signature bytes over binary serialized checksums to enable integrity checking for the checksums or null for no integrity checking. PackageManager#requestChecksums will return the certificate used to create signature. Binary format for checksums: 
<code>DataOutputStream dos;
                   dos.writeInt(checksum.getType());
                   dos.writeInt(checksum.getValue().length);
                   dos.write(checksum.getValue());</code>
 If using openssl cms, make sure to specify -binary -nosmimecap.
Exceptions
java.lang.SecurityException if called after the session has been committed or abandoned.
java.lang.IllegalStateException if checksums for this file have already been added.

See Also

    setStagingProgress

    Added in API level 21
    open fun setStagingProgress(progress: Float): Unit

    Set current progress of staging this session. Valid values are anywhere between 0 and 1.

    Note that this progress may not directly correspond to the value reported by SessionCallback#onProgressChanged(int, float), as the system may carve out a portion of the overall progress to represent its own internal installation work.

    transfer

    open fun transfer(packageName: String): Unit

    Transfer the session to a new owner.

    Only sessions that update the installing app can be transferred.

    After the transfer to a package with a different uid all method calls on the session will cause SecurityExceptions.

    Once this method is called, the session is sealed and no additional mutations beside committing it may be performed on the session.

    Parameters
    packageName String: The package of the new owner. Needs to hold the INSTALL_PACKAGES permission. This value cannot be null.
    Exceptions
    android.content.pm.PackageManager.NameNotFoundException if the new owner could not be found.
    java.lang.SecurityException if called after the session has been committed or abandoned.
    java.lang.IllegalStateException if streams opened through are still open.