NdefRecord
class NdefRecord : Parcelable
kotlin.Any | |
↳ | android.nfc.NdefRecord |
Represents an immutable NDEF Record.
NDEF (NFC Data Exchange Format) is a light-weight binary format, used to encapsulate typed data. It is specified by the NFC Forum, for transmission and storage with NFC, however it is transport agnostic.
NDEF defines messages and records. An NDEF Record contains typed data, such as MIME-type media, a URI, or a custom application payload. An NDEF Message is a container for one or more NDEF Records.
This class represents logical (complete) NDEF Records, and can not be used to represent chunked (partial) NDEF Records. However NdefMessage.NdefMessage(byte[])
can be used to parse a message containing chunked records, and will return a message with unchunked (complete) records.
A logical NDEF Record always contains a 3-bit TNF (Type Name Field) that provides high level typing for the rest of the record. The remaining fields are variable length and not always present:
- type: detailed typing for the payload
- id: identifier meta-data, not commonly used
- payload: the actual payload
Helpers such as android.nfc.NdefRecord#createUri, NdefRecord.createMime
and NdefRecord.createExternal
are included to create well-formatted NDEF Records with correctly set tnf, type, id and payload fields, please use these helpers whenever possible.
Use the constructor NdefRecord(short,byte[],byte[],byte[])
if you know what you are doing and what to set the fields individually. Only basic validation is performed with this constructor, so it is possible to create records that do not confirm to the strict NFC Forum specifications.
The binary representation of an NDEF Record includes additional flags to indicate location with an NDEF message, provide support for chunking of NDEF records, and to pack optional fields. This class does not expose those details. To write an NDEF Record as binary you must first put it into an NdefMessage
, then call NdefMessage.toByteArray()
.
NdefMessage
and NdefRecord
implementations are always available, even on Android devices that do not have NFC hardware.
NdefRecord
s are intended to be immutable (and thread-safe), however they may contain mutable fields. So take care not to modify mutable fields passed into constructors, or modify mutable fields obtained by getter methods, unless such modification is explicitly marked as safe.
Summary
Constants | |
---|---|
static Short |
Indicates the type field contains an absolute-URI BNF construct defined by RFC 3986. |
static Short |
Indicates the record is empty. |
static Short |
Indicates the type field contains an external type name. |
static Short |
Indicates the type field contains a media-type BNF construct, defined by RFC 2046. |
static Short |
Indicates the payload is an intermediate or final chunk of a chunked NDEF Record. |
static Short |
Indicates the payload type is unknown. |
static Short |
Indicates the type field contains a well-known RTD type name. |
Inherited constants | |
---|---|
Public constructors | |
---|---|
NdefRecord(data: ByteArray!) Construct an NDEF Record from raw bytes. |
|
NdefRecord(tnf: Short, type: ByteArray!, id: ByteArray!, payload: ByteArray!) Construct an NDEF Record from its component fields. |
Public methods | |
---|---|
static NdefRecord! |
createApplicationRecord(packageName: String!) Create a new Android Application Record (AAR). |
static NdefRecord! |
createExternal(domain: String!, type: String!, data: ByteArray!) Create a new NDEF Record containing external (application-specific) data. |
static NdefRecord! |
createMime(mimeType: String!, mimeData: ByteArray!) Create a new NDEF Record containing MIME data. |
static NdefRecord! |
createTextRecord(languageCode: String!, text: String!) Create a new NDEF record containing UTF-8 text data. |
static NdefRecord! |
Create a new NDEF Record containing a URI. |
static NdefRecord! |
Create a new NDEF Record containing a URI. |
Int | |
Boolean |
Returns true if the specified NDEF Record contains identical tnf, type, id and payload fields. |
ByteArray! |
getId() Returns the variable length ID. |
ByteArray! |
Returns the variable length payload. |
Short |
getTnf() Returns the 3-bit TNF. |
ByteArray! |
getType() Returns the variable length Type field. |
Int |
hashCode() |
ByteArray! |
Return this NDEF Record as a byte array. |
String! |
Map this record to a MIME type, or return null if it cannot be mapped. |
String |
toString() |
Uri! |
toUri() Map this record to a URI, or return null if it cannot be mapped. |
Unit |
writeToParcel(dest: Parcel, flags: Int) |
Properties | |
---|---|
static Parcelable.Creator<NdefRecord!> | |
static ByteArray! |
RTD Alternative Carrier type. |
static ByteArray! |
RTD Handover Carrier type. |
static ByteArray! |
RTD Handover Request type. |
static ByteArray! |
RTD Handover Select type. |
static ByteArray! |
RTD Smart Poster type. |
static ByteArray! |
RTD Text type. |
static ByteArray! |
RTD URI type. |
Constants
TNF_ABSOLUTE_URI
static val TNF_ABSOLUTE_URI: Short
Indicates the type field contains an absolute-URI BNF construct defined by RFC 3986.
When creating new records prefer #createUri, since it offers more compact URI encoding (#RTD_URI allows compression of common URI prefixes).
Value: 3
See Also
TNF_EMPTY
static val TNF_EMPTY: Short
Indicates the record is empty.
Type, id and payload fields are empty in a TNF_EMPTY record.
Value: 0
TNF_EXTERNAL_TYPE
static val TNF_EXTERNAL_TYPE: Short
Indicates the type field contains an external type name.
Used to encode custom payloads. When creating new records use the helper createExternal
.
The external-type RTD format is specified in NFCForum-TS-RTD_1.0.
Note this TNF should not be used with RTD_TEXT or RTD_URI constants. Those are well known RTD constants, not external RTD constants.
Value: 4
See Also
TNF_MIME_MEDIA
static val TNF_MIME_MEDIA: Short
Indicates the type field contains a media-type BNF construct, defined by RFC 2046.
Use this with MIME type names such as "image/jpeg", or using the helper createMime
.
Value: 2
See Also
TNF_UNCHANGED
static val TNF_UNCHANGED: Short
Indicates the payload is an intermediate or final chunk of a chunked NDEF Record.
TNF_UNCHANGED can not be used with this class since all NdefRecord
s are already unchunked, however they may appear in the binary format.
Value: 6
TNF_UNKNOWN
static val TNF_UNKNOWN: Short
Indicates the payload type is unknown.
NFC Forum explains this should be treated similarly to the "application/octet-stream" MIME type. The payload type is not explicitly encoded within the record.
The type field is empty in an TNF_UNKNOWN record.
Value: 5
TNF_WELL_KNOWN
static val TNF_WELL_KNOWN: Short
Indicates the type field contains a well-known RTD type name.
Use this tnf with RTD types such as RTD_TEXT
, RTD_URI
.
The RTD type name format is specified in NFCForum-TS-RTD_1.0.
Value: 1
See Also
Public constructors
NdefRecord
NdefRecord(data: ByteArray!)
Deprecated: use NdefMessage.NdefMessage(byte[])
instead.
Construct an NDEF Record from raw bytes.
This method is deprecated, use NdefMessage.NdefMessage(byte[])
instead. This is because it does not make sense to parse a record: the NDEF binary format is only defined for a message, and the record flags MB and ME do not make sense outside of the context of an entire message.
This implementation will attempt to parse a single record by ignoring the MB and ME flags, and otherwise following the rules of NdefMessage.NdefMessage(byte[])
.
Parameters | |
---|---|
data |
ByteArray!: raw bytes to parse |
Exceptions | |
---|---|
android.nfc.FormatException |
if the data cannot be parsed into a valid record |
NdefRecord
NdefRecord(
tnf: Short,
type: ByteArray!,
id: ByteArray!,
payload: ByteArray!)
Construct an NDEF Record from its component fields.
Recommend to use helpers such as {#createUri} or {createExternal
where possible, since they perform stricter validation that the record is correctly formatted as per NDEF specifications. However if you know what you are doing then this constructor offers the most flexibility.
An NdefRecord
represents a logical (complete) record, and cannot represent NDEF Record chunks.
Basic validation of the tnf, type, id and payload is performed as per the following rules:
- The tnf paramter must be a 3-bit value.
- Records with a tnf of
TNF_EMPTY
cannot have a type, id or payload. - Records with a tnf of
TNF_UNKNOWN
or 0x07 cannot have a type. - Records with a tnf of
TNF_UNCHANGED
are not allowed since this class only represents complete (unchunked) records.
If any of the above validation steps fail then IllegalArgumentException
is thrown.
Deep inspection of the type, id and payload fields is not performed, so it is possible to create NDEF Records that conform to section 3.2.6 but fail other more strict NDEF specification requirements. For example, the payload may be invalid given the tnf and type.
To omit a type, id or payload field, set the parameter to an empty byte array or null.
Parameters | |
---|---|
tnf |
Short: a 3-bit TNF constant |
type |
ByteArray!: byte array, containing zero to 255 bytes, or null |
id |
ByteArray!: byte array, containing zero to 255 bytes, or null |
payload |
ByteArray!: byte array, containing zero to (2 ** 32 - 1) bytes, or null |
Exceptions | |
---|---|
IllegalArugmentException |
if a valid record cannot be created |
Public methods
createApplicationRecord
static fun createApplicationRecord(packageName: String!): NdefRecord!
Create a new Android Application Record (AAR).
This record indicates to other Android devices the package that should be used to handle the entire NDEF message. You can embed this record anywhere into your message to ensure that the intended package receives the message.
When an Android device dispatches an NdefMessage
containing one or more Android application records, the applications contained in those records will be the preferred target for the NfcAdapter.ACTION_NDEF_DISCOVERED
intent, in the order in which they appear in the message. This dispatch behavior was first added to Android in Ice Cream Sandwich.
If none of the applications have a are installed on the device, a Market link will be opened to the first application.
Note that Android application records do not overrule applications that have called NfcAdapter.enableForegroundDispatch
.
Parameters | |
---|---|
packageName |
String!: Android package name |
Return | |
---|---|
NdefRecord! |
Android application NDEF record |
createExternal
static fun createExternal(
domain: String!,
type: String!,
data: ByteArray!
): NdefRecord!
Create a new NDEF Record containing external (application-specific) data.
Use this method to encode application specific data into an NDEF Record. The data is typed by a domain name (usually your Android package name) and a domain-specific type. This data is packaged into a "NFC Forum External Type" NDEF Record.
NFC Forum requires that the domain and type used in an external record are treated as case insensitive, however Android intent filtering is always case sensitive. So this method will force the domain and type to lower-case before creating the NDEF Record.
The unchecked exception IllegalArgumentException
will be thrown if the domain and type have serious problems, for example if either field is empty, so always catch this exception if you are passing user-generated data into this method.
There are no such restrictions on the payload data.
For efficiency, This method might not make an internal copy of the data byte array, so take care not to modify the data byte array while still using the returned NdefRecord. Reference specification: NFCForum-TS-RTD_1.0
Parameters | |
---|---|
domain |
String!: domain-name of issuing organization |
type |
String!: domain-specific type of data |
data |
ByteArray!: payload as bytes |
Exceptions | |
---|---|
IllegalArugmentException |
if either domain or type are empty or invalid |
createMime
static fun createMime(
mimeType: String!,
mimeData: ByteArray!
): NdefRecord!
Create a new NDEF Record containing MIME data.
Use this method to encode MIME-typed data into an NDEF Record, such as "text/plain", or "image/jpeg".
The mimeType parameter will be normalized with Intent.normalizeMimeType
to follow Android best practices for intent filtering, for example to force lower-case. However the unchecked exception IllegalArgumentException
may be thrown if the mimeType parameter has serious problems, for example if it is empty, so always catch this exception if you are passing user-generated data into this method.
For efficiency, This method might not make an internal copy of the mimeData byte array, so take care not to modify the mimeData byte array while still using the returned NdefRecord.
Parameters | |
---|---|
mimeType |
String!: a valid MIME type |
mimeData |
ByteArray!: MIME data as bytes |
Return | |
---|---|
NdefRecord! |
an NDEF Record containing the MIME-typed data |
Exceptions | |
---|---|
IllegalArugmentException |
if the mimeType is empty or invalid |
createTextRecord
static fun createTextRecord(
languageCode: String!,
text: String!
): NdefRecord!
Create a new NDEF record containing UTF-8 text data.
The caller can either specify the language code for the provided text, or otherwise the language code corresponding to the current default locale will be used. Reference specification: NFCForum-TS-RTD_Text_1.0
Parameters | |
---|---|
languageCode |
String!: The languageCode for the record. If locale is empty or null, the language code of the current default locale will be used. |
text |
String!: The text to be encoded in the record. Will be represented in UTF-8 format. |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if text is null |
createUri
static fun createUri(uri: Uri!): NdefRecord!
Create a new NDEF Record containing a URI.
Use this method to encode a URI (or URL) into an NDEF Record.
Uses the well known URI type representation: TNF_WELL_KNOWN
and RTD_URI
. This is the most efficient encoding of a URI into NDEF.
The uri parameter will be normalized with Uri.normalizeScheme
to set the scheme to lower case to follow Android best practices for intent filtering. However the unchecked exception IllegalArgumentException
may be thrown if the uri parameter has serious problems, for example if it is empty, so always catch this exception if you are passing user-generated data into this method.
Reference specification: NFCForum-TS-RTD_URI_1.0
Parameters | |
---|---|
uri |
Uri!: URI to encode. |
Return | |
---|---|
NdefRecord! |
an NDEF Record containing the URI |
Exceptions | |
---|---|
IllegalArugmentException |
if the uri is empty or invalid |
createUri
static fun createUri(uriString: String!): NdefRecord!
Create a new NDEF Record containing a URI.
Use this method to encode a URI (or URL) into an NDEF Record.
Uses the well known URI type representation: TNF_WELL_KNOWN
and RTD_URI
. This is the most efficient encoding of a URI into NDEF.
The uriString parameter will be normalized with Uri.normalizeScheme
to set the scheme to lower case to follow Android best practices for intent filtering. However the unchecked exception IllegalArgumentException
may be thrown if the uriString parameter has serious problems, for example if it is empty, so always catch this exception if you are passing user-generated data into this method.
Reference specification: NFCForum-TS-RTD_URI_1.0
Parameters | |
---|---|
uriString |
String!: string URI to encode. |
Return | |
---|---|
NdefRecord! |
an NDEF Record containing the URI |
Exceptions | |
---|---|
IllegalArugmentException |
if the uriString is empty or invalid |
describeContents
fun describeContents(): Int
Return | |
---|---|
Int |
a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either 0 or android.os.Parcelable#CONTENTS_FILE_DESCRIPTOR |
equals
fun equals(other: Any?): Boolean
Returns true if the specified NDEF Record contains identical tnf, type, id and payload fields.
Parameters | |
---|---|
obj |
This value may be null . |
Return | |
---|---|
Boolean |
true if this object is the same as the obj argument; false otherwise. |
getId
fun getId(): ByteArray!
Returns the variable length ID.
Returns an empty byte array if this record does not have an id field.
getPayload
fun getPayload(): ByteArray!
Returns the variable length payload.
Returns an empty byte array if this record does not have a payload field.
getType
fun getType(): ByteArray!
Returns the variable length Type field.
This should be used in conjunction with the TNF field to determine the payload format.
Returns an empty byte array if this record does not have a type field.
toByteArray
funtoByteArray(): ByteArray!
Deprecated: use NdefMessage.toByteArray()
instead
Return this NDEF Record as a byte array.
This method is deprecated, use NdefMessage.toByteArray
instead. This is because the NDEF binary format is not defined for a record outside of the context of a message: the MB and ME flags cannot be set without knowing the location inside a message.
This implementation will attempt to serialize a single record by always setting the MB and ME flags (in other words, assume this is a single-record NDEF Message).
toMimeType
fun toMimeType(): String!
Map this record to a MIME type, or return null if it cannot be mapped.
Currently this method considers all TNF_MIME_MEDIA
records to be MIME records, as well as some TNF_WELL_KNOWN
records such as RTD_TEXT
. If this is a MIME record then the MIME type as string is returned, otherwise null is returned.
This method does not perform validation that the MIME type is actually valid. It always attempts to return a string containing the type if this is a MIME record.
The returned MIME type will by normalized to lower-case using Intent.normalizeMimeType
.
The MIME payload can be obtained using getPayload
.
Return | |
---|---|
String! |
MIME type as a string, or null if this is not a MIME record |
toString
fun toString(): String
Return | |
---|---|
String |
a string representation of the object. |
toUri
fun toUri(): Uri!
Map this record to a URI, or return null if it cannot be mapped.
Currently this method considers the following to be URI records:
TNF_ABSOLUTE_URI
records.TNF_WELL_KNOWN
with a type ofRTD_URI
.TNF_WELL_KNOWN
with a type ofRTD_SMART_POSTER
and containing a URI record in the NDEF message nested in the payload.TNF_EXTERNAL_TYPE
records.
This method does not perform validation that the URI is actually valid: it always attempts to create and return a URI if this record appears to be a URI record by the above rules.
The returned URI will be normalized to have a lower case scheme using Uri.normalizeScheme
.
Return | |
---|---|
Uri! |
URI, or null if this is not a URI record |
writeToParcel
fun writeToParcel(
dest: Parcel,
flags: Int
): Unit
Parameters | |
---|---|
dest |
Parcel: The Parcel in which the object should be written. This value cannot be null . |
flags |
Int: Additional flags about how the object should be written. May be 0 or PARCELABLE_WRITE_RETURN_VALUE . Value is either 0 or a combination of android.os.Parcelable#PARCELABLE_WRITE_RETURN_VALUE , and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES |
Properties
RTD_ALTERNATIVE_CARRIER
static val RTD_ALTERNATIVE_CARRIER: ByteArray!
RTD Alternative Carrier type. For use with TNF_WELL_KNOWN.
See Also
RTD_HANDOVER_CARRIER
static val RTD_HANDOVER_CARRIER: ByteArray!
RTD Handover Carrier type. For use with TNF_WELL_KNOWN.
See Also
RTD_HANDOVER_REQUEST
static val RTD_HANDOVER_REQUEST: ByteArray!
RTD Handover Request type. For use with TNF_WELL_KNOWN.
See Also
RTD_HANDOVER_SELECT
static val RTD_HANDOVER_SELECT: ByteArray!
RTD Handover Select type. For use with TNF_WELL_KNOWN.
See Also
RTD_SMART_POSTER
static val RTD_SMART_POSTER: ByteArray!
RTD Smart Poster type. For use with TNF_WELL_KNOWN.
See Also
RTD_TEXT
static val RTD_TEXT: ByteArray!
RTD Text type. For use with TNF_WELL_KNOWN.
See Also
RTD_URI
static val RTD_URI: ByteArray!
RTD URI type. For use with TNF_WELL_KNOWN.
See Also