The source code

/**@class android.nfc.tech.Ndef
@extends android.nfc.tech.BasicTagTechnology

 Provides access to NDEF content and operations on a {@link Tag}.

 <p>Acquire a {@link android.nfc.tech.Ndef} object using {@link #get}.

 <p>NDEF is an NFC Forum data format. The data formats are implemented in
 {@link android.nfc.NdefMessage} and
 {@link android.nfc.NdefRecord}. This class provides methods to
 retrieve and modify the {@link android.nfc.NdefMessage}
 on a tag.

 <p>There are currently four NFC Forum standardized tag types that can be
 formatted to contain NDEF data.
 <ul>
 <li>NFC Forum Type 1 Tag ({@link #NFC_FORUM_TYPE_1}), such as the Innovision Topaz
 <li>NFC Forum Type 2 Tag ({@link #NFC_FORUM_TYPE_2}), such as the NXP MIFARE Ultralight
 <li>NFC Forum Type 3 Tag ({@link #NFC_FORUM_TYPE_3}), such as Sony Felica
 <li>NFC Forum Type 4 Tag ({@link #NFC_FORUM_TYPE_4}), such as NXP MIFARE Desfire
 </ul>
 It is mandatory for all Android devices with NFC to correctly enumerate
 {@link android.nfc.tech.Ndef} on NFC Forum Tag Types 1-4, and implement all NDEF operations
 as defined in this class.

 <p>Some vendors have their own well defined specifications for storing NDEF data
 on tags that do not fall into the above categories. Android devices with NFC
 should enumerate and implement {@link android.nfc.tech.Ndef} under these vendor specifications
 where possible, but it is not mandatory. {@link #getType} returns a String
 describing this specification, for example {@link #MIFARE_CLASSIC} is
 <code>com.nxp.ndef.mifareclassic</code>.

 <p>Android devices that support MIFARE Classic must also correctly
 implement {@link android.nfc.tech.Ndef} on MIFARE Classic tags formatted to NDEF.

 <p>For guaranteed compatibility across all Android devices with NFC, it is
 recommended to use NFC Forum Types 1-4 in new deployments of NFC tags
 with NDEF payload. Vendor NDEF formats will not work on all Android devices.

 <p class="note"><strong>Note:</strong> Methods that perform I/O operations
 require the {@link android.Manifest.permission#NFC} permission.
*/
var Ndef = {

/**@hide */
NDEF_MODE_READ_ONLY : "1",
/**@hide */
NDEF_MODE_READ_WRITE : "2",
/**@hide */
NDEF_MODE_UNKNOWN : "3",
/**@hide */
EXTRA_NDEF_MSG : "ndefmsg",
/**@hide */
EXTRA_NDEF_MAXLENGTH : "ndefmaxlength",
/**@hide */
EXTRA_NDEF_CARDSTATE : "ndefcardstate",
/**@hide */
EXTRA_NDEF_TYPE : "ndeftype",
/**@hide */
TYPE_OTHER : "-1",
/**@hide */
TYPE_1 : "1",
/**@hide */
TYPE_2 : "2",
/**@hide */
TYPE_3 : "3",
/**@hide */
TYPE_4 : "4",
/**@hide */
TYPE_MIFARE_CLASSIC : "101",
/**@hide */
TYPE_ICODE_SLI : "102",
/**@hide */
UNKNOWN : "android.ndef.unknown",
/**NFC Forum Tag Type 1 */
NFC_FORUM_TYPE_1 : "org.nfcforum.ndef.type1",
/**NFC Forum Tag Type 2 */
NFC_FORUM_TYPE_2 : "org.nfcforum.ndef.type2",
/**NFC Forum Tag Type 4 */
NFC_FORUM_TYPE_3 : "org.nfcforum.ndef.type3",
/**NFC Forum Tag Type 4 */
NFC_FORUM_TYPE_4 : "org.nfcforum.ndef.type4",
/**NDEF on MIFARE Classic */
MIFARE_CLASSIC : "com.nxp.ndef.mifareclassic",
/** NDEF on iCODE SLI
 @hide
*/
ICODE_SLI : "com.nxp.ndef.icodesli",
/**Get an instance of {@link android.nfc.tech.Ndef} for the given tag.

 <p>Returns null if {@link android.nfc.tech.Ndef} was not enumerated in {@link Tag#getTechList}.
 This indicates the tag is not NDEF formatted, or that this tag
 is NDEF formatted but under a vendor specification that this Android
 device does not implement.

 <p>Does not cause any RF activity and does not block.
@param {Object {Tag}} tag an NDEF compatible tag
@return {Object {android.nfc.tech.Ndef}} Ndef object
*/
get : function(  ) {},

/**Get the {@link android.nfc.tech.NdefMessage} that was read from the tag at discovery time.

 <p>If the NDEF Message is modified by an I/O operation then it
 will not be updated here, this function only returns what was discovered
 when the tag entered the field.
 <p>Note that this method may return null if the tag was in the
 INITIALIZED state as defined by NFC Forum, as in this state the
 tag is formatted to support NDEF but does not contain a message yet.
 <p>Does not cause any RF activity and does not block.
@return {Object {android.nfc.NdefMessage}} NDEF Message read from the tag at discovery time, can be null
*/
getCachedNdefMessage : function(  ) {},

/**Get the NDEF tag type.

 <p>Returns one of {@link #NFC_FORUM_TYPE_1}, {@link #NFC_FORUM_TYPE_2},
 {@link #NFC_FORUM_TYPE_3}, {@link #NFC_FORUM_TYPE_4},
 {@link #MIFARE_CLASSIC} or another NDEF tag type that has not yet been
 formalized in this Android API.

 <p>Does not cause any RF activity and does not block.
@return {String} a string representing the NDEF tag type
*/
getType : function(  ) {},

/**Get the maximum NDEF message size in bytes.

 <p>Does not cause any RF activity and does not block.
@return {Number} size in bytes
*/
getMaxSize : function(  ) {},

/**Determine if the tag is writable.

 <p>NFC Forum tags can be in read-only or read-write states.

 <p>Does not cause any RF activity and does not block.

 <p>Requires {@link android.Manifest.permission#NFC} permission.
@return {Boolean} true if the tag is writable
*/
isWritable : function(  ) {},

/**Read the current {@link android.nfc.NdefMessage} on this tag.

 <p>This always reads the current NDEF Message stored on the tag.

 <p>Note that this method may return null if the tag was in the
 INITIALIZED state as defined by NFC Forum, as in that state the
 tag is formatted to support NDEF but does not contain a message yet.

 <p>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
 {@link IOException} if {@link #close} is called from another thread.

 <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
@return {Object {android.nfc.NdefMessage}} the NDEF Message, can be null
@throws TagLostException if the tag leaves the field
@throws IOException if there is an I/O failure, or the operation is canceled
@throws FormatException if the NDEF Message on the tag is malformed
*/
getNdefMessage : function(  ) {},

/**Overwrite the {@link android.nfc.tech.NdefMessage} on this tag.

 <p>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
 {@link IOException} if {@link #close} is called from another thread.

 <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
@param {Object {NdefMessage}} msg the NDEF Message to write, must not be null
@throws TagLostException if the tag leaves the field
@throws IOException if there is an I/O failure, or the operation is canceled
@throws FormatException if the NDEF Message to write is malformed
*/
writeNdefMessage : function(  ) {},

/**Indicates whether a tag can be made read-only with {@link #makeReadOnly}().

 <p>Does not cause any RF activity and does not block.
@return {Boolean} true if it is possible to make this tag read-only
*/
canMakeReadOnly : function(  ) {},

/**Make a tag read-only.

 <p>This sets the CC field to indicate the tag is read-only,
 and where possible permanently sets the lock bits to prevent
 any further modification of the memory.
 <p>This is a one-way process and cannot be reverted!

 <p>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
 {@link IOException} if {@link #close} is called from another thread.

 <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
@return {Boolean} true on success, false if it is not possible to make this tag read-only
@throws TagLostException if the tag leaves the field
@throws IOException if there is an I/O failure, or the operation is canceled
*/
makeReadOnly : function(  ) {},


};