https://source.android.com/ 
/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.nfc;

import android.content.Intent;
import android.net.Uri;
import android.os.Parcel;
import android.os.Parcelable;

import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;


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(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 createUri, createMime and 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. 
 NdefRecords 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. 
See Also:
/**
 * Represents an immutable NDEF Record.
 * <p>
 * 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.
 * <p>
 * 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.
 * <p>
 * This class represents logical (complete) NDEF Records, and can not be
 * used to represent chunked (partial) NDEF Records. However
 * {@link NdefMessage#NdefMessage(byte[])} can be used to parse a message
 * containing chunked records, and will return a message with unchunked
 * (complete) records.
 * <p>
 * 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:
 * <ul>
 * <li><em>type</em>: detailed typing for the payload</li>
 * <li><em>id</em>: identifier meta-data, not commonly used</li>
 * <li><em>payload</em>: the actual payload</li>
 * </ul>
 * <p>
 * Helpers such as {@link NdefRecord#createUri}, {@link NdefRecord#createMime}
 * and {@link 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.
 * <p>
 * Use the constructor {@link #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.
 * <p>
 * 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 {@link NdefMessage}, then call {@link NdefMessage#toByteArray()}.
 * <p class="note">
 * {@link NdefMessage} and {@link NdefRecord} implementations are
 * always available, even on Android devices that do not have NFC hardware.
 * <p class="note">
 * {@link 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.
 *
 * @see NfcAdapter#ACTION_NDEF_DISCOVERED
 * @see NdefMessage
 */
public final class NdefRecord implements Parcelable {
    
Indicates the record is empty.
 Type, id and payload fields are empty in a TNF_EMPTY record. 
/**
     * Indicates the record is empty.<p>
     * Type, id and payload fields are empty in a {@literal TNF_EMPTY} record.
     */
    public static final short TNF_EMPTY = 0x00;

    
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.

See Also:
/**
     * Indicates the type field contains a well-known RTD type name.<p>
     * Use this tnf with RTD types such as {@link #RTD_TEXT}, {@link #RTD_URI}.
     * <p>
     * The RTD type name format is specified in NFCForum-TS-RTD_1.0.
     *
     * @see #RTD_URI
     * @see #RTD_TEXT
     * @see #RTD_SMART_POSTER
     * @see #createUri
     */
    public static final short TNF_WELL_KNOWN = 0x01;

    
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. 
See Also:
/**
     * Indicates the type field contains a media-type BNF
     * construct, defined by RFC 2046.<p>
     * Use this with MIME type names such as {@literal "image/jpeg"}, or
     * using the helper {@link #createMime}.
     *
     * @see #createMime
     */
    public static final short TNF_MIME_MEDIA = 0x02;

    
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). 
See Also:
/**
     * Indicates the type field contains an absolute-URI
     * BNF construct defined by RFC 3986.<p>
     * When creating new records prefer {@link #createUri},
     * since it offers more compact URI encoding
     * ({@literal #RTD_URI} allows compression of common URI prefixes).
     *
     * @see #createUri
     */
    public static final short TNF_ABSOLUTE_URI = 0x03;

    
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.

See Also:
/**
     * Indicates the type field contains an external type name.<p>
     * Used to encode custom payloads. When creating new records
     * use the helper {@link #createExternal}.<p>
     * The external-type RTD format is specified in NFCForum-TS-RTD_1.0.<p>
     * <p>
     * Note this TNF should not be used with RTD_TEXT or RTD_URI constants.
     * Those are well known RTD constants, not external RTD constants.
     *
     * @see #createExternal
     */
    public static final short TNF_EXTERNAL_TYPE = 0x04;

    
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. 
/**
     * Indicates the payload type is unknown.<p>
     * 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.
     * <p>
     * The type field is empty in an {@literal TNF_UNKNOWN} record.
     */
    public static final short TNF_UNKNOWN = 0x05;

    
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 NdefRecords are already unchunked, however they may appear in the binary format. 
/**
     * Indicates the payload is an intermediate or final chunk of a chunked
     * NDEF Record.<p>
     * {@literal TNF_UNCHANGED} can not be used with this class
     * since all {@link NdefRecord}s are already unchunked, however they
     * may appear in the binary format.
     */
    public static final short TNF_UNCHANGED = 0x06;

    
Reserved TNF type.


The NFC Forum NDEF Specification v1.0 suggests for NDEF parsers to treat this
value like TNF_UNKNOWN.

@hide
/**
     * Reserved TNF type.
     * <p>
     * The NFC Forum NDEF Specification v1.0 suggests for NDEF parsers to treat this
     * value like TNF_UNKNOWN.
     * @hide
     */
    public static final short TNF_RESERVED = 0x07;

    
RTD Text type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Text type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_TEXT = {0x54};  // "T"

    
RTD URI type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD URI type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_URI = {0x55};   // "U"

    
RTD Smart Poster type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Smart Poster type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_SMART_POSTER = {0x53, 0x70};  // "Sp"

    
RTD Alternative Carrier type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Alternative Carrier type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_ALTERNATIVE_CARRIER = {0x61, 0x63};  // "ac"

    
RTD Handover Carrier type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Handover Carrier type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_HANDOVER_CARRIER = {0x48, 0x63};  // "Hc"

    
RTD Handover Request type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Handover Request type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_HANDOVER_REQUEST = {0x48, 0x72};  // "Hr"

    
RTD Handover Select type. For use with TNF_WELL_KNOWN. 
See Also:
/**
     * RTD Handover Select type. For use with {@literal TNF_WELL_KNOWN}.
     * @see #TNF_WELL_KNOWN
     */
    public static final byte[] RTD_HANDOVER_SELECT = {0x48, 0x73}; // "Hs"

    
RTD Android app type. For use with TNF_EXTERNAL. 
 The payload of a record with type RTD_ANDROID_APP should be the package name identifying an application. Multiple RTD_ANDROID_APP records may be included in a single NdefMessage. 
 Use createApplicationRecord(String) to create RTD_ANDROID_APP records. 
@hide
/**
     * RTD Android app type. For use with {@literal TNF_EXTERNAL}.
     * <p>
     * The payload of a record with type RTD_ANDROID_APP
     * should be the package name identifying an application.
     * Multiple RTD_ANDROID_APP records may be included
     * in a single {@link NdefMessage}.
     * <p>
     * Use {@link #createApplicationRecord(String)} to create
     * RTD_ANDROID_APP records.
     * @hide
     */
    public static final byte[] RTD_ANDROID_APP = "android.com:pkg".getBytes();

    private static final byte FLAG_MB = (byte) 0x80;
    private static final byte FLAG_ME = (byte) 0x40;
    private static final byte FLAG_CF = (byte) 0x20;
    private static final byte FLAG_SR = (byte) 0x10;
    private static final byte FLAG_IL = (byte) 0x08;

    
NFC Forum "URI Record Type Definition"

This is a mapping of "URI Identifier Codes" to URI string prefixes,
per section 3.2.2 of the NFC Forum URI Record Type Definition document.

/**
     * NFC Forum "URI Record Type Definition"<p>
     * This is a mapping of "URI Identifier Codes" to URI string prefixes,
     * per section 3.2.2 of the NFC Forum URI Record Type Definition document.
     */
    private static final String[] URI_PREFIX_MAP = new String[] {
            "", // 0x00
            "http://www.", // 0x01
            "https://www.", // 0x02
            "http://", // 0x03
            "https://", // 0x04
            "tel:", // 0x05
            "mailto:", // 0x06
            "ftp://anonymous:anonymous@", // 0x07
            "ftp://ftp.", // 0x08
            "ftps://", // 0x09
            "sftp://", // 0x0A
            "smb://", // 0x0B
            "nfs://", // 0x0C
            "ftp://", // 0x0D
            "dav://", // 0x0E
            "news:", // 0x0F
            "telnet://", // 0x10
            "imap:", // 0x11
            "rtsp://", // 0x12
            "urn:", // 0x13
            "pop:", // 0x14
            "sip:", // 0x15
            "sips:", // 0x16
            "tftp:", // 0x17
            "btspp://", // 0x18
            "btl2cap://", // 0x19
            "btgoep://", // 0x1A
            "tcpobex://", // 0x1B
            "irdaobex://", // 0x1C
            "file://", // 0x1D
            "urn:epc:id:", // 0x1E
            "urn:epc:tag:", // 0x1F
            "urn:epc:pat:", // 0x20
            "urn:epc:raw:", // 0x21
            "urn:epc:", // 0x22
            "urn:nfc:", // 0x23
    };

    private static final int MAX_PAYLOAD_SIZE = 10 * (1 << 20);  // 10 MB payload limit

    private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];

    private final short mTnf;
    private final byte[] mType;
    private final byte[] mId;
    private final byte[] mPayload;

    
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. 
Params:
  • packageName – Android package name
Returns:Android application NDEF record
/**
     * Create a new Android Application Record (AAR).
     * <p>
     * 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.
     * <p>
     * When an Android device dispatches an {@link NdefMessage}
     * containing one or more Android application records,
     * the applications contained in those records will be the
     * preferred target for the {@link 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.
     * <p>
     * If none of the applications have a are installed on the device,
     * a Market link will be opened to the first application.
     * <p>
     * Note that Android application records do not overrule
     * applications that have called
     * {@link NfcAdapter#enableForegroundDispatch}.
     *
     * @param packageName Android package name
     * @return Android application NDEF record
     */
    public static NdefRecord createApplicationRecord(String packageName) {
        if (packageName == null) throw new NullPointerException("packageName is null");
        if (packageName.length() == 0) throw new IllegalArgumentException("packageName is empty");

        return new NdefRecord(TNF_EXTERNAL_TYPE, RTD_ANDROID_APP, null,
                packageName.getBytes(StandardCharsets.UTF_8));
    }

    
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

Params:
  • uri – URI to encode.
Throws:
  • IllegalArugmentException – if the uri is empty or invalid
Returns:an NDEF Record containing the URI
/**
     * Create a new NDEF Record containing a URI.<p>
     * Use this method to encode a URI (or URL) into an NDEF Record.<p>
     * Uses the well known URI type representation: {@link #TNF_WELL_KNOWN}
     * and {@link #RTD_URI}. This is the most efficient encoding
     * of a URI into NDEF.<p>
     * The uri parameter will be normalized with
     * {@link Uri#normalizeScheme} to set the scheme to lower case to
     * follow Android best practices for intent filtering.
     * However the unchecked exception
     * {@link 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.<p>
     *
     * Reference specification: NFCForum-TS-RTD_URI_1.0
     *
     * @param uri URI to encode.
     * @return an NDEF Record containing the URI
     * @throws IllegalArugmentException if the uri is empty or invalid
     */
    public static NdefRecord createUri(Uri uri) {
        if (uri == null) throw new NullPointerException("uri is null");

        uri = uri.normalizeScheme();
        String uriString = uri.toString();
        if (uriString.length() == 0) throw new IllegalArgumentException("uri is empty");

        byte prefix = 0;
        for (int i = 1; i < URI_PREFIX_MAP.length; i++) {
            if (uriString.startsWith(URI_PREFIX_MAP[i])) {
                prefix = (byte) i;
                uriString = uriString.substring(URI_PREFIX_MAP[i].length());
                break;
            }
        }
        byte[] uriBytes = uriString.getBytes(StandardCharsets.UTF_8);
        byte[] recordBytes = new byte[uriBytes.length + 1];
        recordBytes[0] = prefix;
        System.arraycopy(uriBytes, 0, recordBytes, 1, uriBytes.length);
        return new NdefRecord(TNF_WELL_KNOWN, RTD_URI, null, recordBytes);
    }

    
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

Params:
  • uriString – string URI to encode.
Throws:
  • IllegalArugmentException – if the uriString is empty or invalid
Returns:an NDEF Record containing the URI
/**
     * Create a new NDEF Record containing a URI.<p>
     * Use this method to encode a URI (or URL) into an NDEF Record.<p>
     * Uses the well known URI type representation: {@link #TNF_WELL_KNOWN}
     * and {@link #RTD_URI}. This is the most efficient encoding
     * of a URI into NDEF.<p>
      * The uriString parameter will be normalized with
     * {@link Uri#normalizeScheme} to set the scheme to lower case to
     * follow Android best practices for intent filtering.
     * However the unchecked exception
     * {@link 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.<p>
     *
     * Reference specification: NFCForum-TS-RTD_URI_1.0
     *
     * @param uriString string URI to encode.
     * @return an NDEF Record containing the URI
     * @throws IllegalArugmentException if the uriString is empty or invalid
     */
    public static NdefRecord createUri(String uriString) {
        return createUri(Uri.parse(uriString));
    }

    
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.

Params:
  • mimeType – a valid MIME type
  • mimeData – MIME data as bytes
Throws:
  • IllegalArugmentException – if the mimeType is empty or invalid
Returns:an NDEF Record containing the MIME-typed data
/**
     * Create a new NDEF Record containing MIME data.<p>
     * Use this method to encode MIME-typed data into an NDEF Record,
     * such as "text/plain", or "image/jpeg".<p>
     * The mimeType parameter will be normalized with
     * {@link Intent#normalizeMimeType} to follow Android best
     * practices for intent filtering, for example to force lower-case.
     * However the unchecked exception
     * {@link 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.
     * <p>
     * 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.
     *
     * @param mimeType a valid MIME type
     * @param mimeData MIME data as bytes
     * @return an NDEF Record containing the MIME-typed data
     * @throws IllegalArugmentException if the mimeType is empty or invalid
     *
     */
    public static NdefRecord createMime(String mimeType, byte[] mimeData) {
        if (mimeType == null) throw new NullPointerException("mimeType is null");

        // We only do basic MIME type validation: trying to follow the
        // RFCs strictly only ends in tears, since there are lots of MIME
        // types in common use that are not strictly valid as per RFC rules
        mimeType = Intent.normalizeMimeType(mimeType);
        if (mimeType.length() == 0) throw new IllegalArgumentException("mimeType is empty");
        int slashIndex = mimeType.indexOf('/');
        if (slashIndex == 0) throw new IllegalArgumentException("mimeType must have major type");
        if (slashIndex == mimeType.length() - 1) {
            throw new IllegalArgumentException("mimeType must have minor type");
        }
        // missing '/' is allowed

        // MIME RFCs suggest ASCII encoding for content-type
        byte[] typeBytes = mimeType.getBytes(StandardCharsets.US_ASCII);
        return new NdefRecord(TNF_MIME_MEDIA, typeBytes, null, mimeData);
    }

    
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

Params:
  • domain – domain-name of issuing organization
  • type – domain-specific type of data
  • data – payload as bytes
Throws:
  • IllegalArugmentException – if either domain or type are empty or invalid
/**
     * Create a new NDEF Record containing external (application-specific) data.<p>
     * 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.<p>
     * 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.<p>
     * The unchecked exception {@link 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.<p>
     * There are no such restrictions on the payload data.<p>
     * 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
     * @param domain domain-name of issuing organization
     * @param type domain-specific type of data
     * @param data payload as bytes
     * @throws IllegalArugmentException if either domain or type are empty or invalid
     */
    public static NdefRecord createExternal(String domain, String type, byte[] data) {
        if (domain == null) throw new NullPointerException("domain is null");
        if (type == null) throw new NullPointerException("type is null");

        domain = domain.trim().toLowerCase(Locale.ROOT);
        type = type.trim().toLowerCase(Locale.ROOT);

        if (domain.length() == 0) throw new IllegalArgumentException("domain is empty");
        if (type.length() == 0) throw new IllegalArgumentException("type is empty");

        byte[] byteDomain = domain.getBytes(StandardCharsets.UTF_8);
        byte[] byteType = type.getBytes(StandardCharsets.UTF_8);
        byte[] b = new byte[byteDomain.length + 1 + byteType.length];
        System.arraycopy(byteDomain, 0, b, 0, byteDomain.length);
        b[byteDomain.length] = ':';
        System.arraycopy(byteType, 0, b, byteDomain.length + 1, byteType.length);

        return new NdefRecord(TNF_EXTERNAL_TYPE, b, null, data);
    }

    
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

Params:
  • languageCode – The languageCode for the record. If locale is empty or null,
                    the language code of the current default locale will be used.
  • text –   The text to be encoded in the record. Will be represented in UTF-8 format.
Throws:
/**
     * Create a new NDEF record containing UTF-8 text data.<p>
     *
     * 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
     * @param languageCode The languageCode for the record. If locale is empty or null,
     *                     the language code of the current default locale will be used.
     * @param text   The text to be encoded in the record. Will be represented in UTF-8 format.
     * @throws IllegalArgumentException if text is null
     */
    public static NdefRecord createTextRecord(String languageCode, String text) {
        if (text == null) throw new NullPointerException("text is null");

        byte[] textBytes = text.getBytes(StandardCharsets.UTF_8);

        byte[] languageCodeBytes = null;
        if (languageCode != null && !languageCode.isEmpty()) {
            languageCodeBytes = languageCode.getBytes(StandardCharsets.US_ASCII);
        } else {
            languageCodeBytes = Locale.getDefault().getLanguage().
                    getBytes(StandardCharsets.US_ASCII);
        }
        // We only have 6 bits to indicate ISO/IANA language code.
        if (languageCodeBytes.length >= 64) {
            throw new IllegalArgumentException("language code is too long, must be <64 bytes.");
        }
        ByteBuffer buffer = ByteBuffer.allocate(1 + languageCodeBytes.length + textBytes.length);

        byte status = (byte) (languageCodeBytes.length & 0xFF);
        buffer.put(status);
        buffer.put(languageCodeBytes);
        buffer.put(textBytes);

        return new NdefRecord(TNF_WELL_KNOWN, RTD_TEXT, null, buffer.array());
    }

    
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.
    • 


This minimal validation is specified by
NFCForum-TS-NDEF_1.0 section 3.2.6 (Type Name Format).
 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.

Params:
  • tnf –  a 3-bit TNF constant
  • type – byte array, containing zero to 255 bytes, or null
  • id –   byte array, containing zero to 255 bytes, or null
  • payload – byte array, containing zero to (2 ** 32 - 1) bytes,
               or null
Throws:
  • IllegalArugmentException – if a valid record cannot be created
/**
     * Construct an NDEF Record from its component fields.<p>
     * Recommend to use helpers such as {#createUri} or
     * {{@link #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.<p>
     * An {@link NdefRecord} represents a logical (complete)
     * record, and cannot represent NDEF Record chunks.<p>
     * Basic validation of the tnf, type, id and payload is performed
     * as per the following rules:
     * <ul>
     * <li>The tnf paramter must be a 3-bit value.</li>
     * <li>Records with a tnf of {@link #TNF_EMPTY} cannot have a type,
     * id or payload.</li>
     * <li>Records with a tnf of {@link #TNF_UNKNOWN} or {@literal 0x07}
     * cannot have a type.</li>
     * <li>Records with a tnf of {@link #TNF_UNCHANGED} are not allowed
     * since this class only represents complete (unchunked) records.</li>
     * </ul>
     * This minimal validation is specified by
     * NFCForum-TS-NDEF_1.0 section 3.2.6 (Type Name Format).<p>
     * If any of the above validation
     * steps fail then {@link IllegalArgumentException} is thrown.<p>
     * 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.
     * <p>
     * To omit a type, id or payload field, set the parameter to an
     * empty byte array or null.
     *
     * @param tnf  a 3-bit TNF constant
     * @param type byte array, containing zero to 255 bytes, or null
     * @param id   byte array, containing zero to 255 bytes, or null
     * @param payload byte array, containing zero to (2 ** 32 - 1) bytes,
     *                or null
     * @throws IllegalArugmentException if a valid record cannot be created
     */
    public NdefRecord(short tnf, byte[] type, byte[] id, byte[] payload) {
        /* convert nulls */
        if (type == null) type = EMPTY_BYTE_ARRAY;
        if (id == null) id = EMPTY_BYTE_ARRAY;
        if (payload == null) payload = EMPTY_BYTE_ARRAY;

        String message = validateTnf(tnf, type, id, payload);
        if (message != null) {
            throw new IllegalArgumentException(message);
        }

        mTnf = tnf;
        mType = type;
        mId = id;
        mPayload = payload;
    }

    
Construct an NDEF Record from raw bytes.
 This method is deprecated, use 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(byte[]).


Params:
  • data – raw bytes to parse
Throws:
Deprecated:use NdefMessage(byte[]) instead.
/**
     * Construct an NDEF Record from raw bytes.<p>
     * This method is deprecated, use {@link 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.<p>
     * This implementation will attempt to parse a single record by ignoring
     * the MB and ME flags, and otherwise following the rules of
     * {@link NdefMessage#NdefMessage(byte[])}.<p>
     *
     * @param data raw bytes to parse
     * @throws FormatException if the data cannot be parsed into a valid record
     * @deprecated use {@link NdefMessage#NdefMessage(byte[])} instead.
     */
    @Deprecated
    public NdefRecord(byte[] data) throws FormatException {
        ByteBuffer buffer = ByteBuffer.wrap(data);
        NdefRecord[] rs = parse(buffer, true);

        if (buffer.remaining() > 0) {
            throw new FormatException("data too long");
        }

        mTnf = rs[0].mTnf;
        mType = rs[0].mType;
        mId = rs[0].mId;
        mPayload = rs[0].mPayload;
    }

    
Returns the 3-bit TNF.


TNF is the top-level type.

/**
     * Returns the 3-bit TNF.
     * <p>
     * TNF is the top-level type.
     */
    public short getTnf() {
        return mTnf;
    }

    
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.

/**
     * Returns the variable length Type field.
     * <p>
     * This should be used in conjunction with the TNF field to determine the
     * payload format.
     * <p>
     * Returns an empty byte array if this record
     * does not have a type field.
     */
    public byte[] getType() {
        return mType.clone();
    }

    
Returns the variable length ID.


Returns an empty byte array if this record
does not have an id field.

/**
     * Returns the variable length ID.
     * <p>
     * Returns an empty byte array if this record
     * does not have an id field.
     */
    public byte[] getId() {
        return mId.clone();
    }

    
Returns the variable length payload.


Returns an empty byte array if this record
does not have a payload field.

/**
     * Returns the variable length payload.
     * <p>
     * Returns an empty byte array if this record
     * does not have a payload field.
     */
    public byte[] getPayload() {
        return mPayload.clone();
    }

    
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).


Deprecated:use NdefMessage.toByteArray() instead
/**
     * Return this NDEF Record as a byte array.<p>
     * This method is deprecated, use {@link 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.<p>
     * 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).<p>
     *
     * @deprecated use {@link NdefMessage#toByteArray()} instead
     */
    @Deprecated
    public byte[] toByteArray() {
        ByteBuffer buffer = ByteBuffer.allocate(getByteLength());
        writeToByteBuffer(buffer, true, true);
        return buffer.array();
    }

    
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. 
Returns:MIME type as a string, or null if this is not a MIME record
/**
     * Map this record to a MIME type, or return null if it cannot be mapped.<p>
     * Currently this method considers all {@link #TNF_MIME_MEDIA} records to
     * be MIME records, as well as some {@link #TNF_WELL_KNOWN} records such as
     * {@link #RTD_TEXT}. If this is a MIME record then the MIME type as string
     * is returned, otherwise null is returned.<p>
     * 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.<p>
     * The returned MIME type will by normalized to lower-case using
     * {@link Intent#normalizeMimeType}.<p>
     * The MIME payload can be obtained using {@link #getPayload}.
     *
     * @return MIME type as a string, or null if this is not a MIME record
     */
    public String toMimeType() {
        switch (mTnf) {
            case NdefRecord.TNF_WELL_KNOWN:
                if (Arrays.equals(mType, NdefRecord.RTD_TEXT)) {
                    return "text/plain";
                }
                break;
            case NdefRecord.TNF_MIME_MEDIA:
                String mimeType = new String(mType, StandardCharsets.US_ASCII);
                return Intent.normalizeMimeType(mimeType);
        }
        return null;
    }

    
Map this record to a URI, or return null if it cannot be mapped.

Currently this method considers the following to be URI records:


If this is not a URI record by the above rules, then null is returned.

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.


Returns:URI, or null if this is not a URI record
/**
     * Map this record to a URI, or return null if it cannot be mapped.<p>
     * Currently this method considers the following to be URI records:
     * <ul>
     * <li>{@link #TNF_ABSOLUTE_URI} records.</li>
     * <li>{@link #TNF_WELL_KNOWN} with a type of {@link #RTD_URI}.</li>
     * <li>{@link #TNF_WELL_KNOWN} with a type of {@link #RTD_SMART_POSTER}
     * and containing a URI record in the NDEF message nested in the payload.
     * </li>
     * <li>{@link #TNF_EXTERNAL_TYPE} records.</li>
     * </ul>
     * If this is not a URI record by the above rules, then null is returned.<p>
     * 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.<p>
     * The returned URI will be normalized to have a lower case scheme
     * using {@link Uri#normalizeScheme}.<p>
     *
     * @return URI, or null if this is not a URI record
     */
    public Uri toUri() {
        return toUri(false);
    }

    private Uri toUri(boolean inSmartPoster) {
        switch (mTnf) {
            case TNF_WELL_KNOWN:
                if (Arrays.equals(mType, RTD_SMART_POSTER) && !inSmartPoster) {
                    try {
                        // check payload for a nested NDEF Message containing a URI
                        NdefMessage nestedMessage = new NdefMessage(mPayload);
                        for (NdefRecord nestedRecord : nestedMessage.getRecords()) {
                            Uri uri = nestedRecord.toUri(true);
                            if (uri != null) {
                                return uri;
                            }
                        }
                    } catch (FormatException e) {  }
                } else if (Arrays.equals(mType, RTD_URI)) {
                    Uri wktUri = parseWktUri();
                    return (wktUri != null ? wktUri.normalizeScheme() : null);
                }
                break;

            case TNF_ABSOLUTE_URI:
                Uri uri = Uri.parse(new String(mType, StandardCharsets.UTF_8));
                return uri.normalizeScheme();

            case TNF_EXTERNAL_TYPE:
                if (inSmartPoster) {
                    break;
                }
                return Uri.parse("vnd.android.nfc://ext/" + new String(mType, StandardCharsets.US_ASCII));
        }
        return null;
    }

    
Return complete URI of TNF_WELL_KNOWN, RTD_URI records. 
Returns:complete URI, or null if invalid
/**
     * Return complete URI of {@link #TNF_WELL_KNOWN}, {@link #RTD_URI} records.
     * @return complete URI, or null if invalid
     */
    private Uri parseWktUri() {
        if (mPayload.length < 2) {
            return null;
        }

        // payload[0] contains the URI Identifier Code, as per
        // NFC Forum "URI Record Type Definition" section 3.2.2.
        int prefixIndex = (mPayload[0] & (byte)0xFF);
        if (prefixIndex < 0 || prefixIndex >= URI_PREFIX_MAP.length) {
            return null;
        }
        String prefix = URI_PREFIX_MAP[prefixIndex];
        String suffix = new String(Arrays.copyOfRange(mPayload, 1, mPayload.length),
                StandardCharsets.UTF_8);
        return Uri.parse(prefix + suffix);
    }

    
Main record parsing method.

Expects NdefMessage to begin immediately, allows trailing data.

Currently has strict validation of all fields as per NDEF 1.0
specification section 2.5. We will attempt to keep this as strict as
possible to encourage well-formatted NDEF.

Always returns 1 or more NdefRecord's, or throws FormatException.

Params:
  • buffer – ByteBuffer to read from
  • ignoreMbMe – ignore MB and ME flags, and read only 1 complete record
Throws:
Returns:one or more records
/**
     * Main record parsing method.<p>
     * Expects NdefMessage to begin immediately, allows trailing data.<p>
     * Currently has strict validation of all fields as per NDEF 1.0
     * specification section 2.5. We will attempt to keep this as strict as
     * possible to encourage well-formatted NDEF.<p>
     * Always returns 1 or more NdefRecord's, or throws FormatException.
     *
     * @param buffer ByteBuffer to read from
     * @param ignoreMbMe ignore MB and ME flags, and read only 1 complete record
     * @return one or more records
     * @throws FormatException on any parsing error
     */
    static NdefRecord[] parse(ByteBuffer buffer, boolean ignoreMbMe) throws FormatException {
        List<NdefRecord> records = new ArrayList<NdefRecord>();

        try {
            byte[] type = null;
            byte[] id = null;
            byte[] payload = null;
            ArrayList<byte[]> chunks = new ArrayList<byte[]>();
            boolean inChunk = false;
            short chunkTnf = -1;
            boolean me = false;

            while (!me) {
                byte flag = buffer.get();

                boolean mb = (flag & NdefRecord.FLAG_MB) != 0;
                me = (flag & NdefRecord.FLAG_ME) != 0;
                boolean cf = (flag & NdefRecord.FLAG_CF) != 0;
                boolean sr = (flag & NdefRecord.FLAG_SR) != 0;
                boolean il = (flag & NdefRecord.FLAG_IL) != 0;
                short tnf = (short)(flag & 0x07);

                if (!mb && records.size() == 0 && !inChunk && !ignoreMbMe) {
                    throw new FormatException("expected MB flag");
                } else if (mb && (records.size() != 0 || inChunk) && !ignoreMbMe) {
                    throw new FormatException("unexpected MB flag");
                } else if (inChunk && il) {
                    throw new FormatException("unexpected IL flag in non-leading chunk");
                } else if (cf && me) {
                    throw new FormatException("unexpected ME flag in non-trailing chunk");
                } else if (inChunk && tnf != NdefRecord.TNF_UNCHANGED) {
                    throw new FormatException("expected TNF_UNCHANGED in non-leading chunk");
                } else if (!inChunk && tnf == NdefRecord.TNF_UNCHANGED) {
                    throw new FormatException("" +
                            "unexpected TNF_UNCHANGED in first chunk or unchunked record");
                }

                int typeLength = buffer.get() & 0xFF;
                long payloadLength = sr ? (buffer.get() & 0xFF) : (buffer.getInt() & 0xFFFFFFFFL);
                int idLength = il ? (buffer.get() & 0xFF) : 0;

                if (inChunk && typeLength != 0) {
                    throw new FormatException("expected zero-length type in non-leading chunk");
                }

                if (!inChunk) {
                    type = (typeLength > 0 ? new byte[typeLength] : EMPTY_BYTE_ARRAY);
                    id = (idLength > 0 ? new byte[idLength] : EMPTY_BYTE_ARRAY);
                    buffer.get(type);
                    buffer.get(id);
                }

                ensureSanePayloadSize(payloadLength);
                payload = (payloadLength > 0 ? new byte[(int)payloadLength] : EMPTY_BYTE_ARRAY);
                buffer.get(payload);

                if (cf && !inChunk) {
                    // first chunk
                    if (typeLength == 0 && tnf != NdefRecord.TNF_UNKNOWN) {
                        throw new FormatException("expected non-zero type length in first chunk");
                    }
                    chunks.clear();
                    chunkTnf = tnf;
                }
                if (cf || inChunk) {
                    // any chunk
                    chunks.add(payload);
                }
                if (!cf && inChunk) {
                    // last chunk, flatten the payload
                    payloadLength = 0;
                    for (byte[] p : chunks) {
                        payloadLength += p.length;
                    }
                    ensureSanePayloadSize(payloadLength);
                    payload = new byte[(int)payloadLength];
                    int i = 0;
                    for (byte[] p : chunks) {
                        System.arraycopy(p, 0, payload, i, p.length);
                        i += p.length;
                    }
                    tnf = chunkTnf;
                }
                if (cf) {
                    // more chunks to come
                    inChunk = true;
                    continue;
                } else {
                    inChunk = false;
                }

                String error = validateTnf(tnf, type, id, payload);
                if (error != null) {
                    throw new FormatException(error);
                }
                records.add(new NdefRecord(tnf, type, id, payload));
                if (ignoreMbMe) {  // for parsing a single NdefRecord
                    break;
                }
            }
        } catch (BufferUnderflowException e) {
            throw new FormatException("expected more data", e);
        }
        return records.toArray(new NdefRecord[records.size()]);
    }

    private static void ensureSanePayloadSize(long size) throws FormatException {
        if (size > MAX_PAYLOAD_SIZE) {
            throw new FormatException(
                    "payload above max limit: " + size + " > " + MAX_PAYLOAD_SIZE);
        }
    }

    
Perform simple validation that the tnf is valid.

Validates the requirements of NFCForum-TS-NDEF_1.0 section
3.2.6 (Type Name Format). This just validates that the tnf
is valid, and that the relevant type, id and payload
fields are present (or empty) for this tnf. It does not
perform any deep inspection of the type, id and payload fields.

Also does not allow TNF_UNCHANGED since this class is only used
to present logical (unchunked) records.

Returns:null if valid, or a string error if invalid.
/**
     * Perform simple validation that the tnf is valid.<p>
     * Validates the requirements of NFCForum-TS-NDEF_1.0 section
     * 3.2.6 (Type Name Format). This just validates that the tnf
     * is valid, and that the relevant type, id and payload
     * fields are present (or empty) for this tnf. It does not
     * perform any deep inspection of the type, id and payload fields.<p>
     * Also does not allow TNF_UNCHANGED since this class is only used
     * to present logical (unchunked) records.
     *
     * @return null if valid, or a string error if invalid.
     */
    static String validateTnf(short tnf, byte[] type, byte[] id, byte[] payload) {
        switch (tnf) {
            case TNF_EMPTY:
                if (type.length != 0 || id.length != 0 || payload.length != 0) {
                    return "unexpected data in TNF_EMPTY record";
                }
                return null;
            case TNF_WELL_KNOWN:
            case TNF_MIME_MEDIA:
            case TNF_ABSOLUTE_URI:
            case TNF_EXTERNAL_TYPE:
                return null;
            case TNF_UNKNOWN:
            case TNF_RESERVED:
                if (type.length != 0) {
                    return "unexpected type field in TNF_UNKNOWN or TNF_RESERVEd record";
                }
                return null;
            case TNF_UNCHANGED:
                return "unexpected TNF_UNCHANGED in first chunk or logical record";
            default:
                return String.format("unexpected tnf value: 0x%02x", tnf);
        }
    }

    
Serialize record for network transmission.

Uses specified MB and ME flags.

Does not chunk records.

/**
     * Serialize record for network transmission.<p>
     * Uses specified MB and ME flags.<p>
     * Does not chunk records.
     */
    void writeToByteBuffer(ByteBuffer buffer, boolean mb, boolean me) {
        boolean sr = mPayload.length < 256;
        boolean il = mTnf == TNF_EMPTY ? true : mId.length > 0;

        byte flags = (byte)((mb ? FLAG_MB : 0) | (me ? FLAG_ME : 0) |
                (sr ? FLAG_SR : 0) | (il ? FLAG_IL : 0) | mTnf);
        buffer.put(flags);

        buffer.put((byte)mType.length);
        if (sr) {
            buffer.put((byte)mPayload.length);
        } else {
            buffer.putInt(mPayload.length);
        }
        if (il) {
            buffer.put((byte)mId.length);
        }

        buffer.put(mType);
        buffer.put(mId);
        buffer.put(mPayload);
    }

    
Get byte length of serialized record.

/**
     * Get byte length of serialized record.
     */
    int getByteLength() {
        int length = 3 + mType.length + mId.length + mPayload.length;

        boolean sr = mPayload.length < 256;
        boolean il = mTnf == TNF_EMPTY ? true : mId.length > 0;

        if (!sr) length += 3;
        if (il) length += 1;

        return length;
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(mTnf);
        dest.writeInt(mType.length);
        dest.writeByteArray(mType);
        dest.writeInt(mId.length);
        dest.writeByteArray(mId);
        dest.writeInt(mPayload.length);
        dest.writeByteArray(mPayload);
    }

    public static final Parcelable.Creator<NdefRecord> CREATOR =
            new Parcelable.Creator<NdefRecord>() {
        @Override
        public NdefRecord createFromParcel(Parcel in) {
            short tnf = (short)in.readInt();
            int typeLength = in.readInt();
            byte[] type = new byte[typeLength];
            in.readByteArray(type);
            int idLength = in.readInt();
            byte[] id = new byte[idLength];
            in.readByteArray(id);
            int payloadLength = in.readInt();
            byte[] payload = new byte[payloadLength];
            in.readByteArray(payload);

            return new NdefRecord(tnf, type, id, payload);
        }
        @Override
        public NdefRecord[] newArray(int size) {
            return new NdefRecord[size];
        }
    };

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + Arrays.hashCode(mId);
        result = prime * result + Arrays.hashCode(mPayload);
        result = prime * result + mTnf;
        result = prime * result + Arrays.hashCode(mType);
        return result;
    }

    
Returns true if the specified NDEF Record contains
identical tnf, type, id and payload fields.

/**
     * Returns true if the specified NDEF Record contains
     * identical tnf, type, id and payload fields.
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        NdefRecord other = (NdefRecord) obj;
        if (!Arrays.equals(mId, other.mId)) return false;
        if (!Arrays.equals(mPayload, other.mPayload)) return false;
        if (mTnf != other.mTnf) return false;
        return Arrays.equals(mType, other.mType);
    }

    @Override
    public String toString() {
        StringBuilder b = new StringBuilder(String.format("NdefRecord tnf=%X", mTnf));
        if (mType.length > 0) b.append(" type=").append(bytesToString(mType));
        if (mId.length > 0) b.append(" id=").append(bytesToString(mId));
        if (mPayload.length > 0) b.append(" payload=").append(bytesToString(mPayload));
        return b.toString();
    }

    private static StringBuilder bytesToString(byte[] bs) {
        StringBuilder s = new StringBuilder();
        for (byte b : bs) {
            s.append(String.format("%02X", b));
        }
        return s;
    }
}