Added in API level 10

NfcA


class NfcA : TagTechnology
kotlin.Any
   ↳ android.nfc.tech.NfcA

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

Acquire a NfcA object using get.

The primary NFC-A 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

Unit

static NfcA!
get(tag: Tag!)

Get an instance of NfcA for the given tag.

ByteArray!

Return the ATQA/SENS_RES bytes from tag discovery.

Int

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

Short

Return the SAK/SEL_RES bytes from tag discovery.

Tag!

Int

Get the current transceive timeout in milliseconds.

Boolean

Unit
setTimeout(timeout: Int)

Set the transceive timeout in milliseconds.

ByteArray!

Send raw NFC-A 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!): NfcA!

Get an instance of NfcA for the given tag.

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

Does not cause any RF activity and does not block.

Parameters
tag Tag!: an NFC-A compatible tag
Return
NfcA! NFC-A object

getAtqa

Added in API level 10
fun getAtqa(): ByteArray!

Return the ATQA/SENS_RES bytes from tag discovery.

Does not cause any RF activity and does not block.

Return
ByteArray! ATQA/SENS_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.

getSak

Added in API level 10
fun getSak(): Short

Return the SAK/SEL_RES bytes from tag discovery.

Does not cause any RF activity and does not block.

Return
Short SAK bytes

getTag

Added in API level 10
fun getTag(): Tag!
Return
Tag! the Tag backing this TagTechnology object.

getTimeout

Added in API level 14
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

isConnected

Added in API level 10
fun isConnected(): Boolean
Return
Boolean true if I/O operations should be possible

setTimeout

Added in API level 14
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

Added in API level 10
fun transceive(data: ByteArray!): ByteArray!

Send raw NFC-A 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 only send commands that are complete bytes, for example a SENS_REQ is not possible (these are used to manage tag polling and initialization).

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