IsoDep

close

void close ()

Disable I/O operations to the tag from this TagTechnology object, and release resources.

Also causes all blocked I/O operations on other thread to be canceled and return with IOException.

Requires the NFC permission.

connect

void connect ()

Enable I/O operations to the tag from this TagTechnology object.

May cause RF activity and may block. Must not be called from the main application thread. A blocked call will be canceled with IOException by calling close() from another thread.

Only one TagTechnology object can be connected to a Tag at a time.

Applications must call close() when I/O operations are complete.

Requires the NFC permission.

get

IsoDep get (Tag tag)

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 getTechList(). This indicates the tag does not support ISO-DEP.

getHiLayerResponse

byte[] getHiLayerResponse ()

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.

getHistoricalBytes

byte[] getHistoricalBytes ()

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.

getMaxTransceiveLength

int getMaxTransceiveLength ()

Return the maximum number of bytes that can be sent with transceive(byte[]).

getTag

Tag getTag ()

Get the Tag object backing this TagTechnology object.

getTimeout

int getTimeout ()

Get the current timeout for transceive(byte[]) in milliseconds.

Requires the NFC permission.

isConnected

boolean isConnected ()

Helper to indicate if I/O operations should be possible.

Returns true if connect() has completed, and close() has not been called, and the Tag is not known to be out of range.

Does not cause RF activity, and does not block.

isExtendedLengthApduSupported

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.

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.

setTimeout

void setTimeout (int timeout)

Set the timeout of transceive(byte[]) in milliseconds.

The timeout only applies to ISO-DEP transceive(byte[]), 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 NFC permission.

transceive

byte[] transceive (byte[] data)

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(byte[]) if it exceeds FSD/FSC limits.

Use getMaxTransceiveLength() to retrieve the maximum number of bytes that can be sent with transceive(byte[]).

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 NFC permission.