MifareUltralight
class MifareUltralight : TagTechnology
| kotlin.Any | |
| ↳ | android.nfc.tech.MifareUltralight |
Provides access to MIFARE Ultralight properties and I/O operations on a Tag.
Acquire a MifareUltralight object using get.
MIFARE Ultralight compatible tags have 4 byte pages PAGE_SIZE. The primary operations on an Ultralight tag are readPages and writePage.
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.
Summary
| Constants | |
|---|---|
| static Int |
Size of a MIFARE Ultralight page in bytes |
| static Int |
A MIFARE Ultralight tag |
| static Int |
A MIFARE Ultralight C tag |
| static Int |
A MIFARE Ultralight compatible tag of unknown type |
| Public methods | |
|---|---|
| Unit |
close() |
| Unit |
connect() |
| static MifareUltralight! |
Get an instance of |
| Int |
Return the maximum number of bytes that can be sent with |
| Tag! |
getTag() |
| Int |
Get the current |
| Int |
getType()Return the MIFARE Ultralight type of the tag. |
| Boolean | |
| ByteArray! |
Read 4 pages (16 bytes). |
| Unit |
setTimeout(timeout: Int)Set the |
| ByteArray! |
transceive(data: ByteArray!)Send raw NfcA data to a tag and receive the response. |
| Unit |
Write 1 page (4 bytes). |
Constants
PAGE_SIZE
static val PAGE_SIZE: Int
Size of a MIFARE Ultralight page in bytes
Value: 4
TYPE_ULTRALIGHT
static val TYPE_ULTRALIGHT: Int
A MIFARE Ultralight tag
Value: 1
TYPE_ULTRALIGHT_C
static val TYPE_ULTRALIGHT_C: Int
A MIFARE Ultralight C tag
Value: 2
TYPE_UNKNOWN
static val TYPE_UNKNOWN: Int
A MIFARE Ultralight compatible tag of unknown type
Value: -1
Public methods
close
fun close(): Unit
| Exceptions | |
|---|---|
java.lang.Exception |
if this resource cannot be closed |
java.io.IOException |
if an I/O error occurs |
java.lang.SecurityException |
if the tag object is reused after the tag has left the field |
connect
fun connect(): Unit
| Exceptions | |
|---|---|
TagLostException |
if the tag leaves the field |
java.io.IOException |
if there is an I/O failure, or connect is canceled |
java.lang.SecurityException |
if the tag object is reused after the tag has left the field |
get
static fun get(tag: Tag!): MifareUltralight!
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 |
| Return | |
|---|---|
MifareUltralight! |
MIFARE Ultralight object |
getMaxTransceiveLength
fun getMaxTransceiveLength(): Int
Return the maximum number of bytes that can be sent with transceive.
| Return | |
|---|---|
Int |
the maximum number of bytes that can be sent with transceive. |
getTag
fun getTag(): Tag!
| Return | |
|---|---|
Tag! |
the Tag backing this TagTechnology object. |
getTimeout
fun getTimeout(): Int
Get the current transceive timeout in milliseconds.
Requires the android.Manifest.permission#NFC permission.
| Return | |
|---|---|
Int |
timeout value in milliseconds |
| Exceptions | |
|---|---|
java.lang.SecurityException |
if the tag object is reused after the tag has left the field |
getType
fun getType(): Int
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.
| Return | |
|---|---|
Int |
the type |
isConnected
fun isConnected(): Boolean
| Return | |
|---|---|
Boolean |
true if I/O operations should be possible |
readPages
fun readPages(pageOffset: Int): ByteArray!
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 android.Manifest.permission#NFC permission.
| Parameters | |
|---|---|
pageOffset |
Int: index of first page to read, starting from 0 |
| Return | |
|---|---|
ByteArray! |
4 pages (16 bytes) |
| Exceptions | |
|---|---|
android.nfc.TagLostException |
if the tag leaves the field |
java.io.IOException |
if there is an I/O failure, or the operation is canceled |
setTimeout
fun setTimeout(timeout: Int): Unit
Set the transceive timeout in milliseconds.
The timeout only applies to transceive 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.
| Parameters | |
|---|---|
timeout |
Int: timeout value in milliseconds |
| Exceptions | |
|---|---|
java.lang.SecurityException |
if the tag object is reused after the tag has left the field |
transceive
fun transceive(data: ByteArray!): ByteArray!
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.
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.
See Also
writePage
fun writePage(
pageOffset: Int,
data: ByteArray!
): Unit
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 android.Manifest.permission#NFC permission.
| Parameters | |
|---|---|
pageOffset |
Int: index of page to write, starting from 0 |
data |
ByteArray!: 4 bytes to write |
| Exceptions | |
|---|---|
android.nfc.TagLostException |
if the tag leaves the field |
java.io.IOException |
if there is an I/O failure, or the operation is canceled |