IsoDep

Kotlin |Java

class IsoDep : TagTechnology

kotlin.Any
↳	android.nfc.tech.IsoDep

Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations on a Tag.

Acquire an IsoDep object using get.

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

Tags that enumerate the IsoDep technology in Tag.getTechList will also enumerate NfcA or NfcB (since IsoDep builds on top of either of these).

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

Summary

Public methods
Unit	`close()`
Unit	`connect()`
static IsoDep!	`get(tag: Tag!)` Get an instance of `IsoDep` for the given tag.
ByteArray!	`getHiLayerResponse()` Return the higher layer response bytes for `NfcB` tags.
ByteArray!	`getHistoricalBytes()` Return the ISO-DEP historical bytes for `NfcA` tags.
Int	`getMaxTransceiveLength()` Return the maximum number of bytes that can be sent with `transceive`.
Tag!	`getTag()`
Int	`getTimeout()` Get the current timeout for `transceive` in milliseconds.
Boolean	`isConnected()`
Boolean	`isExtendedLengthApduSupported()` Standard APDUs have a 1-byte length field, allowing a maximum of 255 payload bytes, which results in a maximum APDU length of 261 bytes.
Unit	`setTimeout(timeout: Int)` Set the timeout of `transceive` in milliseconds.
ByteArray!	`transceive(data: ByteArray!)` Send raw ISO-DEP data 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!): IsoDep!

Get an instance of IsoDep for the given tag.

Does not cause any RF activity and does not block.

Returns null if IsoDep was not enumerated in Tag.getTechList. This indicates the tag does not support ISO-DEP.

Parameters
`tag`	Tag!: an ISO-DEP compatible tag

Return
`IsoDep!`	ISO-DEP object

getHiLayerResponse

Added in API level 10

fun getHiLayerResponse(): ByteArray!

Return the higher layer response bytes for NfcB tags.

Does not cause any RF activity and does not block.

The higher layer response bytes can be used to help identify a tag. They are present only on IsoDep tags that are based on NfcB RF technology. If this tag is not NfcB then null is returned.

In ISO 14443-4 terminology, the higher layer bytes are a subset of the ATTRIB response.

Return
`ByteArray!`	ISO-DEP historical bytes, or null if this is not a `NfcB` tag

getHistoricalBytes

Added in API level 10

fun getHistoricalBytes(): ByteArray!

Return the ISO-DEP historical bytes for NfcA tags.

Does not cause any RF activity and does not block.

The historical bytes can be used to help identify a tag. They are present only on IsoDep tags that are based on NfcA RF technology. If this tag is not NfcA then null is returned.

In ISO 14443-4 terminology, the historical bytes are a subset of the RATS response.

Return
`ByteArray!`	ISO-DEP historical bytes, or null if this is not a `NfcA` tag

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`.

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 timeout for transceive 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

isExtendedLengthApduSupported

Added in API level 16

fun isExtendedLengthApduSupported(): Boolean

Standard APDUs have a 1-byte length field, allowing a maximum of 255 payload bytes, which results in a maximum APDU length of 261 bytes.

Extended length APDUs have a 3-byte length field, allowing 65535 payload bytes.

Some NFC adapters, like the one used in the Nexus S and the Galaxy Nexus do not support extended length APDUs. They are expected to be well-supported in the future though. Use this method to check for extended length APDU support.

Return
`Boolean`	whether the NFC adapter on this device supports extended length APDUs.

Exceptions
`java.lang.SecurityException`	if the tag object is reused after the tag has left the field

setTimeout

Added in API level 10

fun setTimeout(timeout: Int): Unit

Set the timeout of transceive in milliseconds.

The timeout only applies to ISO-DEP transceive, 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 ISO-DEP data to the tag and receive the response.

Applications must only send the INF payload, and not the start of frame and end of frame indicators. Applications do not need to fragment the payload, it will be automatically fragmented and defragmented by transceive if it exceeds FSD/FSC limits.

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!: command bytes to send, must not be null

Return
`ByteArray!`	response bytes received, will not be null

Exceptions
`TagLostException`	if the tag leaves the field
`java.io.IOException`	if there is an I/O failure, or this operation is canceled
`java.lang.SecurityException`	if the tag object is reused after the tag has left the field