public final class MifareUltralight extends Object
Tag
.
Acquire a MifareUltralight
object using get(android.nfc.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 android.Manifest.permission#NFC
permission.
Modifier and Type | Field and Description |
---|---|
static String |
EXTRA_IS_UL_C |
static int |
PAGE_SIZE
Size of a MIFARE Ultralight page in bytes
|
static int |
TYPE_ULTRALIGHT
A MIFARE Ultralight tag
|
static int |
TYPE_ULTRALIGHT_C
A MIFARE Ultralight C tag
|
static int |
TYPE_UNKNOWN
A MIFARE Ultralight compatible tag of unknown type
|
ISO_DEP, MIFARE_CLASSIC, MIFARE_ULTRALIGHT, NDEF, NDEF_FORMATABLE, NFC_A, NFC_B, NFC_BARCODE, NFC_F, NFC_V
Constructor and Description |
---|
MifareUltralight(Tag tag) |
Modifier and Type | Method and Description |
---|---|
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 |
reconnect()
Re-connect to the
Tag associated with this connection. |
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).
|
public static final int TYPE_UNKNOWN
public static final int TYPE_ULTRALIGHT
public static final int TYPE_ULTRALIGHT_C
public static final int PAGE_SIZE
public static final String EXTRA_IS_UL_C
public MifareUltralight(Tag tag) throws RemoteException
RemoteException
public static MifareUltralight get(Tag tag)
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.
tag
- an MIFARE Ultralight compatible tagpublic int getType()
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.
public byte[] readPages(int pageOffset) throws IOException
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 android.Manifest.permission#NFC
permission.
pageOffset
- index of first page to read, starting from 0TagLostException
- if the tag leaves the fieldIOException
- if there is an I/O failure, or the operation is canceledpublic void writePage(int pageOffset, byte[] data) throws IOException
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 android.Manifest.permission#NFC
permission.
pageOffset
- index of page to write, starting from 0data
- 4 bytes to writeTagLostException
- if the tag leaves the fieldIOException
- if there is an I/O failure, or the operation is canceledpublic byte[] transceive(byte[] data) throws IOException
This is equivalent to connecting to this tag via NfcA
and calling NfcA.transceive(byte[])
. 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 android.Manifest.permission#NFC
permission.
IOException
NfcA.transceive(byte[])
public int getMaxTransceiveLength()
transceive(byte[])
.transceive(byte[])
.public void setTimeout(int timeout)
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 android.Manifest.permission#NFC
permission.
timeout
- timeout value in millisecondspublic int getTimeout()
transceive(byte[])
timeout in milliseconds.
Requires the android.Manifest.permission#NFC
permission.
public Tag getTag()
TagTechnology
Tag
object backing this TagTechnology
object.getTag
in interface TagTechnology
Tag
backing this TagTechnology
object.public boolean isConnected()
TagTechnology
Returns true if TagTechnology.connect()
has completed, and TagTechnology.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.
isConnected
in interface TagTechnology
public void connect() throws IOException
TagTechnology
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 TagTechnology.close()
from another thread.
Only one TagTechnology
object can be connected to a Tag
at a time.
Applications must call TagTechnology.close()
when I/O operations are complete.
Requires the android.Manifest.permission#NFC
permission.
connect
in interface TagTechnology
IOException
- if there is an I/O failure, or connect is canceledTagTechnology.close()
public void reconnect() throws IOException
TagTechnology
Tag
associated with this connection. Reconnecting to a tag can be
used to reset the state of the tag itself.
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 TagTechnology.close()
from another thread.
Requires the android.Manifest.permission#NFC
permission.
reconnect
in interface TagTechnology
IOException
- if there is an I/O failure, or connect is canceledTagTechnology.connect()
,
TagTechnology.close()
public void close() throws IOException
TagTechnology
TagTechnology
object, and release resources.
Also causes all blocked I/O operations on other thread to be canceled and
return with IOException
.
Requires the android.Manifest.permission#NFC
permission.
close
in interface TagTechnology
close
in interface Closeable
close
in interface AutoCloseable
IOException
TagTechnology.connect()