Added in API level 10

Summary: Constants | Methods | Inherited Methods

MifareUltralight

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Kotlin |Java

public final class MifareUltralight
extends Object implements TagTechnology

java.lang.Object
↳	android.nfc.tech.MifareUltralight

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Provides access to MIFARE Ultralight properties and I/O operations on a Tag.

Acquire a MifareUltralight object using get(Tag).

MIFARE Ultralight compatible tags have 4 byte pages PAGE_SIZE. The primary operations on an Ultralight tag are readPages(int) and writePage(int, byte).

The original MIFARE Ultralight consists of a 64 byte EEPROM. The first 4 pages are for the OTP area, manufacturer data, and locking bits. They are readable and some bits are writable. The final 12 pages are the user read/write area. For more information see the NXP data sheet MF0ICU1.

The MIFARE Ultralight C consists of a 192 byte EEPROM. The first 4 pages are for OTP, manufacturer data, and locking bits. The next 36 pages are the user read/write area. The next 4 pages are additional locking bits, counters and authentication configuration and are readable. The final 4 pages are for the authentication key and are not readable. For more information see the NXP data sheet MF0ICU2.

Implementation of this class on a Android NFC device is optional. If it is not implemented, then MifareUltralight will never be enumerated in Tag#getTechList. If it is enumerated, then all MifareUltralight I/O operations will be supported. In either case, NfcA will also be enumerated on the tag, because all MIFARE Ultralight tags are also NfcA tags.

Note: Methods that perform I/O operations require the Manifest.permission.NFC permission.

Summary

Constants
int	PAGE_SIZE Size of a MIFARE Ultralight page in bytes
int	TYPE_ULTRALIGHT A MIFARE Ultralight tag
int	TYPE_ULTRALIGHT_C A MIFARE Ultralight C tag
int	TYPE_UNKNOWN A MIFARE Ultralight compatible tag of unknown type

Public methods
void	close() Disable I/O operations to the tag from this TagTechnology object, and release resources.
void	connect() Enable I/O operations to the tag from this TagTechnology object.
static MifareUltralight	get(Tag tag) Get an instance of MifareUltralight for the given tag.
int	getMaxTransceiveLength() Return the maximum number of bytes that can be sent with transceive(byte).
Tag	getTag() Get the Tag object backing this TagTechnology object.
int	getTimeout() Get the current transceive(byte) timeout in milliseconds.
int	getType() Return the MIFARE Ultralight type of the tag.
boolean	isConnected() Helper to indicate if I/O operations should be possible.
byte[]	readPages(int pageOffset) Read 4 pages (16 bytes).
void	setTimeout(int timeout) Set the transceive(byte) timeout in milliseconds.
byte[]	transceive(byte[] data) Send raw NfcA data to a tag and receive the response.
void	writePage(int pageOffset, byte[] data) Write 1 page (4 bytes).

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.
From interface android.nfc.tech.TagTechnology abstract void close() Disable I/O operations to the tag from this TagTechnology object, and release resources. abstract void connect() Enable I/O operations to the tag from this TagTechnology object. abstract Tag getTag() Get the Tag object backing this TagTechnology object. abstract boolean isConnected() Helper to indicate if I/O operations should be possible.
From interface java.io.Closeable abstract void close() Closes this stream and releases any system resources associated with it.
From interface java.lang.AutoCloseable abstract void close() Closes this resource, relinquishing any underlying resources.

Constants

PAGE_SIZE

Added in API level 10

public static final int PAGE_SIZE

Size of a MIFARE Ultralight page in bytes

Constant Value: 4 (0x00000004)

TYPE_ULTRALIGHT

Added in API level 10

public static final int TYPE_ULTRALIGHT

A MIFARE Ultralight tag

Constant Value: 1 (0x00000001)

TYPE_ULTRALIGHT_C

Added in API level 10

public static final int TYPE_ULTRALIGHT_C

A MIFARE Ultralight C tag

Constant Value: 2 (0x00000002)

TYPE_UNKNOWN

Added in API level 10

public static final int TYPE_UNKNOWN

A MIFARE Ultralight compatible tag of unknown type

Constant Value: -1 (0xffffffff)

Public methods

close

Added in API level 10

public void close ()

Disable I/O operations to the tag from this TagTechnology object, and release resources.

Also causes all blocked I/O operations on other thread to be canceled and return with IOException.

Requires the Manifest.permission.NFC permission.

Throws
IOException

connect

Added in API level 10

public void connect ()

Enable I/O operations to the tag from this TagTechnology object.

May cause RF activity and may block. Must not be called from the main application thread. A blocked call will be canceled with IOException by calling close() from another thread.

Only one TagTechnology object can be connected to a Tag at a time.

Applications must call close() when I/O operations are complete.

Requires the Manifest.permission.NFC permission.

Throws
IOException

get

Added in API level 10

public static MifareUltralight get (Tag tag)

Get an instance of MifareUltralight for the given tag.

Returns null if MifareUltralight was not enumerated in Tag#getTechList - this indicates the tag is not MIFARE Ultralight compatible, or that this Android device does not implement MIFARE Ultralight.

Does not cause any RF activity and does not block.

Parameters
tag	Tag: an MIFARE Ultralight compatible tag

Returns
MifareUltralight	MIFARE Ultralight object

getMaxTransceiveLength

Added in API level 14

public int getMaxTransceiveLength ()

Return the maximum number of bytes that can be sent with transceive(byte).

Returns
int	the maximum number of bytes that can be sent with transceive(byte).

getTag

Added in API level 10

public Tag getTag ()

Get the Tag object backing this TagTechnology object.

Returns
Tag	the Tag backing this TagTechnology object.

getTimeout

Added in API level 14

public int getTimeout ()

Get the current transceive(byte) timeout in milliseconds.

Requires the Manifest.permission.NFC permission.

Returns
int	timeout value in milliseconds

Throws
SecurityException	if the tag object is reused after the tag has left the field

getType

Added in API level 10

public int getType ()

Return the MIFARE Ultralight type of the tag.

One of TYPE_ULTRALIGHT or TYPE_ULTRALIGHT_C or TYPE_UNKNOWN.

Depending on how the tag has been formatted, it can be impossible to accurately classify between original MIFARE Ultralight and Ultralight C. So treat this method as a hint.

Does not cause any RF activity and does not block.

Returns
int	the type

isConnected

Added in API level 10

public boolean isConnected ()

Helper to indicate if I/O operations should be possible.

Returns true if connect() has completed, and close() has not been called, and the Tag is not known to be out of range.

Does not cause RF activity, and does not block.

Returns
boolean	true if I/O operations should be possible

readPages

Added in API level 10

public byte[] readPages (int pageOffset)

Read 4 pages (16 bytes).

The MIFARE Ultralight protocol always reads 4 pages at a time, to reduce the number of commands required to read an entire tag.

If a read spans past the last readable block, then the tag will return pages that have been wrapped back to the first blocks. MIFARE Ultralight tags have readable blocks 0x00 through 0x0F. So a read to block offset 0x0E would return blocks 0x0E, 0x0F, 0x00, 0x01. MIFARE Ultralight C tags have readable blocks 0x00 through 0x2B. So a read to block 0x2A would return blocks 0x2A, 0x2B, 0x00, 0x01.

This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

Requires the Manifest.permission.NFC permission.

Parameters
pageOffset	int: index of first page to read, starting from 0

Returns
byte[]	4 pages (16 bytes)

Throws
TagLostException	if the tag leaves the field
IOException	if there is an I/O failure, or the operation is canceled

setTimeout

Added in API level 14

public void setTimeout (int timeout)

Set the transceive(byte) timeout in milliseconds.

The timeout only applies to transceive(byte) on this object, and is reset to a default value when close() is called.

Setting a longer timeout may be useful when performing transactions that require a long processing time on the tag such as key generation.

Requires the Manifest.permission.NFC permission.

Parameters
timeout	int: timeout value in milliseconds

Throws
SecurityException	if the tag object is reused after the tag has left the field

transceive

Added in API level 10

public byte[] transceive (byte[] data)

Send raw NfcA data to a tag and receive the response.

This is equivalent to connecting to this tag via NfcA and calling NfcA#transceive. Note that all MIFARE Classic tags are based on NfcA technology.

Use getMaxTransceiveLength() to retrieve the maximum number of bytes that can be sent with transceive(byte).

This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

Requires the Manifest.permission.NFC permission.

Parameters
data	byte

Returns
byte[]

Throws
IOException

See also:

• NfcA.transceive(byte)

writePage

Added in API level 10

public void writePage (int pageOffset, 
                byte[] data)

Write 1 page (4 bytes).

The MIFARE Ultralight protocol always writes 1 page at a time, to minimize EEPROM write cycles.

This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

Requires the Manifest.permission.NFC permission.

Parameters
pageOffset	int: index of page to write, starting from 0
data	byte: 4 bytes to write

Throws
TagLostException	if the tag leaves the field
IOException	if there is an I/O failure, or the operation is canceled