IsoDep
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 an instance of |
ByteArray! |
Return the higher layer response bytes for |
ByteArray! |
Return the ISO-DEP historical bytes for |
Int |
Return the maximum number of bytes that can be sent with |
Tag! |
getTag() |
Int |
Get the current timeout for |
Boolean | |
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. |
Unit |
setTimeout(timeout: Int) Set the timeout of |
ByteArray! |
transceive(data: ByteArray!) Send raw ISO-DEP data to the tag and receive the response. |
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!): 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
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
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
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 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
fun isConnected(): Boolean
Return | |
---|---|
Boolean |
true if I/O operations should be possible |
isExtendedLengthApduSupported
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
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
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 |