Android APIs
public final class

MtpDevice

extends Object
java.lang.Object
   ↳ android.mtp.MtpDevice

Class Overview

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 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 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 open(UsbDeviceConnection connection)
Opens the MTP device.
String toString()
Returns a string containing a concise, human-readable description of this object.
Protected Methods
void finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public MtpDevice (UsbDevice device)

Added in API level 12

MtpClient constructor

Parameters
device UsbDevice: the UsbDevice for the MTP or PTP device

Public Methods

public void close ()

Added in API level 12

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.

public boolean deleteObject (int objectHandle)

Added in API level 12

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

public int getDeviceId ()

Added in API level 12

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

Returns
int the device ID

public MtpDeviceInfo getDeviceInfo ()

Added in API level 12

Returns the MtpDeviceInfo for this device

Returns
MtpDeviceInfo the device info

public String getDeviceName ()

Added in API level 12

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

Returns
String the device name

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

Added in API level 12

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

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

Added in API level 12

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

public MtpObjectInfo getObjectInfo (int objectHandle)

Added in API level 12

Retrieves the MtpObjectInfo for an object.

Parameters
objectHandle int: the handle of the object
Returns
MtpObjectInfo the MtpObjectInfo

public long getParent (int objectHandle)

Added in API level 12

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

public long getStorageId (int objectHandle)

Added in API level 12

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

public int[] getStorageIds ()

Added in API level 12

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

public MtpStorageInfo getStorageInfo (int storageId)

Added in API level 12

Retrieves the MtpStorageInfo for a storage unit.

Parameters
storageId int: the ID of the storage unit
Returns
MtpStorageInfo the MtpStorageInfo

public byte[] getThumbnail (int objectHandle)

Added in API level 12

Returns the thumbnail data for an object as a byte array. The size and format of the thumbnail data can be determined via getThumbCompressedSize() and 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

public boolean importFile (int objectHandle, String destPath)

Added in API level 12

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 getExternalStorageDirectory()
Returns
boolean true if the file transfer succeeds

public boolean open (UsbDeviceConnection connection)

Added in API level 12

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
Returns
boolean true if the device was successfully opened.

public String toString ()

Added in API level 12

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:

   getClass().getName() + '@' + Integer.toHexString(hashCode())

See Writing a useful toString method if you intend implementing your own toString method.

Returns
String a printable representation of this object.

Protected Methods

protected void finalize ()

Added in API level 12

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

Throws
Throwable