NfcF

Kotlin |Java

class NfcF : TagTechnology

kotlin.Any
↳	android.nfc.tech.NfcF

Provides access to NFC-F (JIS 6319-4) properties and I/O operations on a Tag.

Acquire a NfcF object using get.

The primary NFC-F 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 NfcF!	`get(tag: Tag!)` Get an instance of `NfcF` for the given tag.
ByteArray!	`getManufacturer()` Return the Manufacturer bytes from tag discovery.
Int	`getMaxTransceiveLength()` Return the maximum number of bytes that can be sent with `transceive`.
ByteArray!	`getSystemCode()` Return the System Code bytes from tag discovery.
Tag!	`getTag()`
Int	`getTimeout()` Get the current `transceive` timeout in milliseconds.
Boolean	`isConnected()`
Unit	`setTimeout(timeout: Int)` Set the `transceive` timeout in milliseconds.
ByteArray!	`transceive(data: ByteArray!)` Send raw NFC-F 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!): NfcF!

Get an instance of NfcF for the given tag.

Returns null if NfcF was not enumerated in Tag.getTechList. This indicates the tag does not support NFC-F.

Does not cause any RF activity and does not block.

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

Return
`NfcF!`	NFC-F object

getManufacturer

Added in API level 10

fun getManufacturer(): ByteArray!

Return the Manufacturer bytes from tag discovery.

Does not cause any RF activity and does not block.

Return
`ByteArray!`	Manufacturer 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`.

getSystemCode

Added in API level 10

fun getSystemCode(): ByteArray!

Return the System Code bytes from tag discovery.

Does not cause any RF activity and does not block.

Return
`ByteArray!`	System Code 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-F commands to the tag and receive the response.

Applications must not prefix the SoD (preamble and sync code) and/or append the EoD (CRC) to the payload, it will be automatically calculated.

A typical NFC-F frame for this method looks like:

LENGTH (1 byte) --- CMD (1 byte) -- IDm (8 bytes) -- PARAMS (LENGTH - 10 bytes)

Use getMaxTransceiveLength to retrieve the maximum amount 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