NfcB

Kotlin |Java

class NfcB : TagTechnology

kotlin.Any
↳	android.nfc.tech.NfcB

Provides access to NFC-B (ISO 14443-3B) properties and I/O operations on a Tag.

Acquire a NfcB object using get.

The primary NFC-B I/O operation is transceive. Applications must implement their own protocol stack on top of transceive.

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

Summary

Public methods
Unit	`close()`
Unit	`connect()`
static NfcB!	`get(tag: Tag!)` Get an instance of `NfcB` for the given tag.
ByteArray!	`getApplicationData()` Return the Application Data bytes from ATQB/SENSB_RES at tag discovery.
Int	`getMaxTransceiveLength()` Return the maximum number of bytes that can be sent with `transceive`.
ByteArray!	`getProtocolInfo()` Return the Protocol Info bytes from ATQB/SENSB_RES at tag discovery.
Tag!	`getTag()`
Boolean	`isConnected()`
ByteArray!	`transceive(data: ByteArray!)` Send raw NFC-B commands to the tag and receive the response.

Public methods

close

Added in API level 10

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

Added in API level 10

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

Added in API level 10

static fun get(tag: Tag!): NfcB!

Get an instance of NfcB for the given tag.

Returns null if NfcB was not enumerated in Tag#getTechList. This indicates the tag does not support NFC-B.

Does not cause any RF activity and does not block.

Parameters
`tag`	Tag!: an NFC-B compatible tag

Return
`NfcB!`	NFC-B object

getApplicationData

Added in API level 10

fun getApplicationData(): ByteArray!

Return the Application Data bytes from ATQB/SENSB_RES at tag discovery.

Does not cause any RF activity and does not block.

Return
`ByteArray!`	Application Data bytes from ATQB/SENSB_RES bytes

getMaxTransceiveLength

Added in API level 14

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`.

getProtocolInfo

Added in API level 10

fun getProtocolInfo(): ByteArray!

Return the Protocol Info bytes from ATQB/SENSB_RES at tag discovery.

Does not cause any RF activity and does not block.

Return
`ByteArray!`	Protocol Info bytes from ATQB/SENSB_RES bytes

getTag

Added in API level 10

fun getTag(): Tag!

Return
`Tag!`	the `Tag` backing this `TagTechnology` object.

isConnected

Added in API level 10

fun isConnected(): Boolean

Return
`Boolean`	true if I/O operations should be possible

transceive

Added in API level 10

fun transceive(data: ByteArray!): ByteArray!

Send raw NFC-B commands to the tag and receive the response.

Applications must not append the EoD (CRC) to the payload, it will be automatically calculated.

Applications must not send commands that manage the polling loop and initialization (SENSB_REQ, SLOT_MARKER etc).

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.

Parameters
`data`	ByteArray!: bytes to send

Return
`ByteArray!`	bytes received in response

Exceptions
`TagLostException`	if the tag leaves the field
`java.io.IOException`	if there is an I/O failure, or this operation is canceled