Added in API level 12

Summary: Ctors | Methods | Protected Methods | Inherited Methods

MtpDevice

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Kotlin |Java

public final class MtpDevice
extends Object

java.lang.Object
↳	android.mtp.MtpDevice

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This class represents an MTP or PTP device connected on the USB host bus. An application can instantiate an object of this type, by referencing an attached UsbDevice and then use methods in this class to get information about the device and objects stored on it, as well as open the connection and transfer data.

Summary

Public constructors
MtpDevice(UsbDevice device) MtpClient constructor

Public methods
void	close() Closes all resources related to the MtpDevice object.
boolean	deleteObject(int objectHandle) Deletes an object on the device.
int	getDeviceId() Returns the USB ID of the USB device.
MtpDeviceInfo	getDeviceInfo() Returns the MtpDeviceInfo for this device
String	getDeviceName() Returns the name of the USB device This returns the same value as UsbDevice.getDeviceName() for the device's UsbDevice
byte[]	getObject(int objectHandle, int objectSize) Returns the data for an object as a byte array.
int[]	getObjectHandles(int storageId, int format, int objectHandle) Returns the list of object handles for all objects on the given storage unit, with the given format and parent.
MtpObjectInfo	getObjectInfo(int objectHandle) Retrieves the MtpObjectInfo for an object.
long	getParent(int objectHandle) Retrieves the object handle for the parent of an object on the device.
long	getPartialObject(int objectHandle, long offset, long size, byte[] buffer) Obtains object bytes in the specified range and writes it to an array.
long	getPartialObject64(int objectHandle, long offset, long size, byte[] buffer) Obtains object bytes in the specified range and writes it to an array.
long	getStorageId(int objectHandle) Retrieves the ID of the storage unit containing the given object on the device.
int[]	getStorageIds() Returns the list of IDs for all storage units on this device Information about each storage unit can be accessed via getStorageInfo(int).
MtpStorageInfo	getStorageInfo(int storageId) Retrieves the MtpStorageInfo for a storage unit.
byte[]	getThumbnail(int objectHandle) Returns the thumbnail data for an object as a byte array.
boolean	importFile(int objectHandle, String destPath) Copies the data for an object to a file in external storage.
boolean	importFile(int objectHandle, ParcelFileDescriptor descriptor) Copies the data for an object to a file descriptor.
boolean	open(UsbDeviceConnection connection) Opens the MTP device.
MtpEvent	readEvent(CancellationSignal signal) Reads an event from the device.
boolean	sendObject(int objectHandle, long size, ParcelFileDescriptor descriptor) Copies the data for an object from a file descriptor.
MtpObjectInfo	sendObjectInfo(MtpObjectInfo info) Uploads an object metadata for a new entry.
String	toString() Returns a string representation of the object.

Protected methods
void	finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

Inherited methods

From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

MtpDevice

Added in API level 12

public MtpDevice (UsbDevice device)

MtpClient constructor

Parameters
device	UsbDevice: the UsbDevice for the MTP or PTP device This value cannot be null.

Public methods

close

Added in API level 12

public void close ()

Closes all resources related to the MtpDevice object. After this is called, the object can not be used until open(UsbDeviceConnection) is called again with a new UsbDeviceConnection.

deleteObject

Added in API level 12

public boolean deleteObject (int objectHandle)

Deletes an object on the device. This call may block, since deleting a directory containing many files may take a long time on some devices.

Parameters
objectHandle	int: handle of the object to delete

Returns
boolean	true if the deletion succeeds

getDeviceId

Added in API level 12

public int getDeviceId ()

Returns the USB ID of the USB device. This returns the same value as UsbDevice.getDeviceId() for the device's UsbDevice

Returns
int	the device ID

getDeviceInfo

Added in API level 12

public MtpDeviceInfo getDeviceInfo ()

Returns the MtpDeviceInfo for this device

Returns
MtpDeviceInfo	the device info, or null if fetching device info fails

getDeviceName

Added in API level 12

public String getDeviceName ()

Returns the name of the USB device This returns the same value as UsbDevice.getDeviceName() for the device's UsbDevice

Returns
String	the device name This value cannot be null.

getObject

Added in API level 12

public byte[] getObject (int objectHandle, 
                int objectSize)

Returns the data for an object as a byte array. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices.

Parameters
objectHandle	int: handle of the object to read
objectSize	int: the size of the object (this should match MtpObjectInfo.getCompressedSize)

Returns
byte[]	the object's data, or null if reading fails

getObjectHandles

Added in API level 12

public int[] getObjectHandles (int storageId, 
                int format, 
                int objectHandle)

Returns the list of object handles for all objects on the given storage unit, with the given format and parent. Information about each object can be accessed via getObjectInfo(int).

Parameters
storageId	int: the storage unit to query
format	int: the format of the object to return, or zero for all formats
objectHandle	int: the parent object to query, -1 for the storage root, or zero for all objects

Returns
int[]	the object handles, or null if fetching object handles fails

getObjectInfo

Added in API level 12

public MtpObjectInfo getObjectInfo (int objectHandle)

Retrieves the MtpObjectInfo for an object.

Parameters
objectHandle	int: the handle of the object

Returns
MtpObjectInfo	the MtpObjectInfo, or null if fetching object info fails

getParent

Added in API level 12

public long getParent (int objectHandle)

Retrieves the object handle for the parent of an object on the device.

Parameters
objectHandle	int: handle of the object to query

Returns
long	the parent's handle, or zero if it is in the root of the storage

getPartialObject

Added in API level 24

public long getPartialObject (int objectHandle, 
                long offset, 
                long size, 
                byte[] buffer)

Obtains object bytes in the specified range and writes it to an array. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices.

Parameters
objectHandle	int: handle of the object to read
offset	long: Start index of reading range. It must be a non-negative value at most 0xffffffff.
size	long: Size of reading range. It must be a non-negative value at most Integer.MAX_VALUE or 0xffffffff. If 0xffffffff is specified, the method obtains the full bytes of object.
buffer	byte: Array to write data. This value cannot be null.

Returns
long	Size of bytes that are actually read.

Throws
IOException

getPartialObject64

Added in API level 24

public long getPartialObject64 (int objectHandle, 
                long offset, 
                long size, 
                byte[] buffer)

Obtains object bytes in the specified range and writes it to an array. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices. This is a vender-extended operation supported by Android that enables us to pass unsigned 64-bit offset. Check if the MTP device supports the operation by using MtpDeviceInfo.getOperationsSupported().

Parameters
objectHandle	int: handle of the object to read
offset	long: Start index of reading range. It must be a non-negative value.
size	long: Size of reading range. It must be a non-negative value at most Integer.MAX_VALUE.
buffer	byte: Array to write data. This value cannot be null.

Returns
long	Size of bytes that are actually read.

Throws
IOException

See also:

• MtpConstants.OPERATION_GET_PARTIAL_OBJECT_64

getStorageId

Added in API level 12

public long getStorageId (int objectHandle)

Retrieves the ID of the storage unit containing the given object on the device.

Parameters
objectHandle	int: handle of the object to query

Returns
long	the object's storage unit ID

getStorageIds

Added in API level 12

public int[] getStorageIds ()

Returns the list of IDs for all storage units on this device Information about each storage unit can be accessed via getStorageInfo(int).

Returns
int[]	the list of storage IDs, or null if fetching storage IDs fails

getStorageInfo

Added in API level 12

public MtpStorageInfo getStorageInfo (int storageId)

Retrieves the MtpStorageInfo for a storage unit.

Parameters
storageId	int: the ID of the storage unit

Returns
MtpStorageInfo	the MtpStorageInfo, or null if fetching storage info fails

getThumbnail

Added in API level 12

public byte[] getThumbnail (int objectHandle)

Returns the thumbnail data for an object as a byte array. The size and format of the thumbnail data can be determined via MtpObjectInfo.getThumbCompressedSize and MtpObjectInfo.getThumbFormat. For typical devices the format is JPEG.

Parameters
objectHandle	int: handle of the object to read

Returns
byte[]	the object's thumbnail, or null if reading fails

importFile

Added in API level 12

public boolean importFile (int objectHandle, 
                String destPath)

Copies the data for an object to a file in external storage. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices.

Parameters
objectHandle	int: handle of the object to read
destPath	String: path to destination for the file transfer. This path should be in the external storage as defined by Environment.getExternalStorageDirectory() This value cannot be null.

Returns
boolean	true if the file transfer succeeds

importFile

Added in API level 24

public boolean importFile (int objectHandle, 
                ParcelFileDescriptor descriptor)

Copies the data for an object to a file descriptor. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices. The file descriptor is not closed on completion, and must be done by the caller.

Parameters
objectHandle	int: handle of the object to read
descriptor	ParcelFileDescriptor: file descriptor to write the data to for the file transfer. This value cannot be null.

Returns
boolean	true if the file transfer succeeds

open

Added in API level 12

public boolean open (UsbDeviceConnection connection)

Opens the MTP device. Once the device is open it takes ownership of the UsbDeviceConnection. The connection will be closed when you call close() The connection will also be closed if this method fails.

Parameters
connection	UsbDeviceConnection: an open UsbDeviceConnection for the device This value cannot be null.

Returns
boolean	true if the device was successfully opened.

readEvent

Added in API level 24

public MtpEvent readEvent (CancellationSignal signal)

Reads an event from the device. It blocks the current thread until it gets an event. It throws OperationCanceledException if it is cancelled by signal.

Parameters
signal	CancellationSignal: signal for cancellation This value may be null.

Returns
MtpEvent	obtained event This value cannot be null.

Throws
	java.io.IOException
IOException

sendObject

Added in API level 24

public boolean sendObject (int objectHandle, 
                long size, 
                ParcelFileDescriptor descriptor)

Copies the data for an object from a file descriptor. This call may block for an arbitrary amount of time depending on the size of the data and speed of the devices. The file descriptor is not closed on completion, and must be done by the caller.

Parameters
objectHandle	int: handle of the target file
size	long: size of the file in bytes
descriptor	ParcelFileDescriptor: file descriptor to read the data from. This value cannot be null.

Returns
boolean	true if the file transfer succeeds

sendObjectInfo

Added in API level 24

public MtpObjectInfo sendObjectInfo (MtpObjectInfo info)

Uploads an object metadata for a new entry. The MtpObjectInfo can be created with the MtpObjectInfo.Builder class. The returned MtpObjectInfo has the new object handle field filled in.

Parameters
info	MtpObjectInfo: metadata of the entry This value cannot be null.

Returns
MtpObjectInfo	object info of the created entry, or null if sending object info fails

toString

Added in API level 12

public String toString ()

Returns a string representation of the object.

Returns
String	This value cannot be null.

Protected methods

finalize

Added in API level 12

protected void finalize ()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

Throws
Throwable