NfcAdapter

ACTION_ADAPTER_STATE_CHANGED

String ACTION_ADAPTER_STATE_CHANGED

Broadcast Action: The state of the local NFC adapter has been changed.

For example, NFC has been turned on or off.

Always contains the extra field EXTRA_ADAPTER_STATE

Constant Value: "android.nfc.action.ADAPTER_STATE_CHANGED"

ACTION_NDEF_DISCOVERED

String ACTION_NDEF_DISCOVERED

Intent to start an activity when a tag with NDEF payload is discovered.

The system inspects the first NdefRecord in the first NdefMessage and looks for a URI, SmartPoster, or MIME record. If a URI or SmartPoster record is found the intent will contain the URI in its data field. If a MIME record is found the intent will contain the MIME type in its type field. This allows activities to register IntentFilters targeting specific content on tags. Activities should register the most specific intent filters possible to avoid the activity chooser dialog, which can disrupt the interaction with the tag as the user interacts with the screen.

If the tag has an NDEF payload this intent is started before ACTION_TECH_DISCOVERED. If any activities respond to this intent neither ACTION_TECH_DISCOVERED or ACTION_TAG_DISCOVERED will be started.

The MIME type or data URI of this intent are normalized before dispatch - so that MIME, URI scheme and URI host are always lower-case.

Constant Value: "android.nfc.action.NDEF_DISCOVERED"

ACTION_TAG_DISCOVERED

String ACTION_TAG_DISCOVERED

Intent to start an activity when a tag is discovered.

This intent will not be started when a tag is discovered if any activities respond to ACTION_NDEF_DISCOVERED or ACTION_TECH_DISCOVERED for the current tag.

Constant Value: "android.nfc.action.TAG_DISCOVERED"

ACTION_TECH_DISCOVERED

String ACTION_TECH_DISCOVERED

Intent to start an activity when a tag is discovered and activities are registered for the specific technologies on the tag.

To receive this intent an activity must include an intent filter for this action and specify the desired tech types in a manifest meta-data entry. Here is an example manfiest entry:

 <activity android:name=".nfc.TechFilter" android:label="NFC/TechFilter">
     <!-- Add a technology filter -->
     <intent-filter>
         <action android:name="android.nfc.action.TECH_DISCOVERED" />
     </intent-filter>

     <meta-data android:name="android.nfc.action.TECH_DISCOVERED"
         android:resource="@xml/filter_nfc"
     />
 </activity>

The meta-data XML file should contain one or more tech-list entries each consisting or one or more tech entries. The tech entries refer to the qualified class name implementing the technology, for example "android.nfc.tech.NfcA".

A tag matches if any of the tech-list sets is a subset of Tag.getTechList(). Each of the tech-lists is considered independently and the activity is considered a match is any single tech-list matches the tag that was discovered. This provides AND and OR semantics for filtering desired techs. Here is an example that will match any tag using NfcF or any tag using NfcA, MifareClassic, and Ndef:

 <resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
     <!-- capture anything using NfcF -->
     <tech-list>
         <tech>android.nfc.tech.NfcF</tech>
     </tech-list>

     <!-- OR -->

     <!-- capture all MIFARE Classics with NDEF payloads -->
     <tech-list>
         <tech>android.nfc.tech.NfcA</tech>
         <tech>android.nfc.tech.MifareClassic</tech>
         <tech>android.nfc.tech.Ndef</tech>
     </tech-list>
 </resources>

This intent is started after ACTION_NDEF_DISCOVERED and before ACTION_TAG_DISCOVERED. If any activities respond to ACTION_NDEF_DISCOVERED this intent will not be started. If any activities respond to this intent ACTION_TAG_DISCOVERED will not be started.

Constant Value: "android.nfc.action.TECH_DISCOVERED"

EXTRA_ADAPTER_STATE

String EXTRA_ADAPTER_STATE

Used as an int extra field in ACTION_ADAPTER_STATE_CHANGED intents to request the current power state. Possible values are: STATE_OFF, STATE_TURNING_ON, STATE_ON, STATE_TURNING_OFF,

Constant Value: "android.nfc.extra.ADAPTER_STATE"

EXTRA_ID

String EXTRA_ID

Optional extra containing a byte array containing the ID of the discovered tag for the ACTION_NDEF_DISCOVERED, ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents.

Constant Value: "android.nfc.extra.ID"

EXTRA_NDEF_MESSAGES

String EXTRA_NDEF_MESSAGES

Extra containing an array of NdefMessage present on the discovered tag.

This extra is mandatory for ACTION_NDEF_DISCOVERED intents, and optional for ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents.

When this extra is present there will always be at least one NdefMessage element. Most NDEF tags have only one NDEF message, but we use an array for future compatibility.

Constant Value: "android.nfc.extra.NDEF_MESSAGES"

EXTRA_READER_PRESENCE_CHECK_DELAY

String EXTRA_READER_PRESENCE_CHECK_DELAY

Int Extra for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this integer extra allows the calling application to specify the delay that the platform will use for performing presence checks on any discovered tag.

Constant Value: "presence"

EXTRA_TAG

String EXTRA_TAG

Mandatory extra containing the Tag that was discovered for the ACTION_NDEF_DISCOVERED, ACTION_TECH_DISCOVERED, and ACTION_TAG_DISCOVERED intents.

Constant Value: "android.nfc.extra.TAG"

FLAG_READER_NFC_A

int FLAG_READER_NFC_A

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag enables polling for Nfc-A technology.

Constant Value: 1 (0x00000001)

FLAG_READER_NFC_B

int FLAG_READER_NFC_B

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag enables polling for Nfc-B technology.

Constant Value: 2 (0x00000002)

FLAG_READER_NFC_BARCODE

int FLAG_READER_NFC_BARCODE

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag enables polling for NfcBarcode technology.

Constant Value: 16 (0x00000010)

FLAG_READER_NFC_F

int FLAG_READER_NFC_F

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag enables polling for Nfc-F technology.

Constant Value: 4 (0x00000004)

FLAG_READER_NFC_V

int FLAG_READER_NFC_V

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag enables polling for Nfc-V (ISO15693) technology.

Constant Value: 8 (0x00000008)

FLAG_READER_NO_PLATFORM_SOUNDS

int FLAG_READER_NO_PLATFORM_SOUNDS

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag allows the caller to prevent the platform from playing sounds when it discovers a tag.

Constant Value: 256 (0x00000100)

FLAG_READER_SKIP_NDEF_CHECK

int FLAG_READER_SKIP_NDEF_CHECK

Flag for use with enableReaderMode(Activity, ReaderCallback, int, Bundle).

Setting this flag allows the caller to prevent the platform from performing an NDEF check on the tags it finds.

Constant Value: 128 (0x00000080)

STATE_OFF

int STATE_OFF

Constant Value: 1 (0x00000001)

STATE_ON

int STATE_ON

Constant Value: 3 (0x00000003)

STATE_TURNING_OFF

int STATE_TURNING_OFF

Constant Value: 4 (0x00000004)

STATE_TURNING_ON

int STATE_TURNING_ON

Constant Value: 2 (0x00000002)

disableForegroundDispatch

void disableForegroundDispatch (Activity activity)

Disable foreground dispatch to the given activity.

After calling enableForegroundDispatch(Activity, PendingIntent, IntentFilter[], String[][]), an activity must call this method before its onPause() callback completes.

This method must be called from the main thread.

Requires the NFC permission.

disableForegroundNdefPush

void disableForegroundNdefPush (Activity activity)

This method was deprecated in API level 14.
use setNdefPushMessage(NdefMessage, Activity, Activity...) instead

Disable NDEF message push over P2P.

After calling enableForegroundNdefPush(Activity, NdefMessage), an activity must call this method before its onPause() callback completes.

Strongly recommend to use the new setNdefPushMessage(NdefMessage, Activity, Activity...) instead: it automatically hooks into your activity life-cycle, so you do not need to call enable/disable in your onResume/onPause.

This method must be called from the main thread.

Requires the NFC permission.

disableReaderMode

void disableReaderMode (Activity activity)

Restore the NFC adapter to normal mode of operation: supporting peer-to-peer (Android Beam), card emulation, and polling for all supported tag technologies.

enableForegroundDispatch

void enableForegroundDispatch (Activity activity, 
                PendingIntent intent, 
                IntentFilter[] filters, 
                String[][] techLists)

Enable foreground dispatch to the given Activity.

This will give give priority to the foreground activity when dispatching a discovered Tag to an application.

If any IntentFilters are provided to this method they are used to match dispatch Intents for both the ACTION_NDEF_DISCOVERED and ACTION_TAG_DISCOVERED. Since ACTION_TECH_DISCOVERED relies on meta data outside of the IntentFilter matching for that dispatch Intent is handled by passing in the tech lists separately. Each first level entry in the tech list represents an array of technologies that must all be present to match. If any of the first level sets match then the dispatch is routed through the given PendingIntent. In other words, the second level is ANDed together and the first level entries are ORed together.

If you pass null for both the filters and techLists parameters that acts a wild card and will cause the foreground activity to receive all tags via the ACTION_TAG_DISCOVERED intent.

This method must be called from the main thread, and only when the activity is in the foreground (resumed). Also, activities must call disableForegroundDispatch(Activity) before the completion of their onPause() callback to disable foreground dispatch after it has been enabled.

Requires the NFC permission.

enableForegroundNdefPush

void enableForegroundNdefPush (Activity activity, 
                NdefMessage message)

This method was deprecated in API level 14.
use setNdefPushMessage(NdefMessage, Activity, Activity...) instead

Enable NDEF message push over NFC while this Activity is in the foreground.

You must explicitly call this method every time the activity is resumed, and you must call disableForegroundNdefPush(Activity) before your activity completes onPause().

Strongly recommend to use the new setNdefPushMessage(NdefMessage, Activity, Activity...) instead: it automatically hooks into your activity life-cycle, so you do not need to call enable/disable in your onResume/onPause.

For NDEF push to function properly the other NFC device must support either NFC Forum's SNEP (Simple Ndef Exchange Protocol), or Android's "com.android.npp" (Ndef Push Protocol). This was optional on Gingerbread level Android NFC devices, but SNEP is mandatory on Ice-Cream-Sandwich and beyond.

This method must be called from the main thread.

Requires the NFC permission.

enableReaderMode

void enableReaderMode (Activity activity, 
                NfcAdapter.ReaderCallback callback, 
                int flags, 
                Bundle extras)

Limit the NFC controller to reader mode while this Activity is in the foreground.

In this mode the NFC controller will only act as an NFC tag reader/writer, thus disabling any peer-to-peer (Android Beam) and card-emulation modes of the NFC adapter on this device.

Use FLAG_READER_SKIP_NDEF_CHECK to prevent the platform from performing any NDEF checks in reader mode. Note that this will prevent the Ndef tag technology from being enumerated on the tag, and that NDEF-based tag dispatch will not be functional.

For interacting with tags that are emulated on another Android device using Android's host-based card-emulation, the recommended flags are FLAG_READER_NFC_A and FLAG_READER_SKIP_NDEF_CHECK.

getDefaultAdapter

NfcAdapter getDefaultAdapter (Context context)

Helper to get the default NFC Adapter.

Most Android devices will only have one NFC Adapter (NFC Controller).

This helper is the equivalent of:

 NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
 NfcAdapter adapter = manager.getDefaultAdapter();

ignore

boolean ignore (Tag tag, 
                int debounceMs, 
                NfcAdapter.OnTagRemovedListener tagRemovedListener, 
                Handler handler)

Signals that you are no longer interested in communicating with an NFC tag for as long as it remains in range. All future attempted communication to this tag will fail with IOException. The NFC controller will be put in a low-power polling mode, allowing the device to save power in cases where it's "attached" to a tag all the time (e.g. a tag in car dock). Additionally the debounceMs parameter allows you to specify for how long the tag needs to have gone out of range, before it will be dispatched again. Note: the NFC controller typically polls at a pretty slow interval (100 - 500 ms). This means that if the tag repeatedly goes in and out of range (for example, in case of a flaky connection), and the controller happens to poll every time the tag is out of range, it *will* re-dispatch the tag after debounceMs, despite the tag having been "in range" during the interval. Note 2: if a tag with another UID is detected after this API is called, its effect will be cancelled; if this tag shows up before the amount of time specified in debounceMs, it will be dispatched again. Note 3: some tags have a random UID, in which case this API won't work reliably.

invokeBeam

boolean invokeBeam (Activity activity)

Manually invoke Android Beam to share data.

The Android Beam animation is normally only shown when two NFC-capable devices come into range. By calling this method, an Activity can invoke the Beam animation directly even if no other NFC device is in range yet. The Beam animation will then prompt the user to tap another NFC-capable device to complete the data transfer.

The main advantage of using this method is that it avoids the need for the user to tap the screen to complete the transfer, as this method already establishes the direction of the transfer and the consent of the user to share data. Callers are responsible for making sure that the user has consented to sharing data on NFC tap.

Note that to use this method, the passed in Activity must have already set data to share over Beam by using method calls such as setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) or setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity).

isEnabled

boolean isEnabled ()

Return true if this NFC Adapter has any features enabled.

If this method returns false, the NFC hardware is guaranteed not to generate or respond to any NFC communication over its NFC radio.

Applications can use this to check if NFC is enabled. Applications can request Settings UI allowing the user to toggle NFC using:

startActivity(new Intent(Settings.ACTION_NFC_SETTINGS))

isNdefPushEnabled

boolean isNdefPushEnabled ()

Return true if the NDEF Push (Android Beam) feature is enabled.

This function will return true only if both NFC is enabled, and the NDEF Push feature is enabled.

Note that if NFC is enabled but NDEF Push is disabled then this device can still receive NDEF messages, it just cannot send them.

Applications cannot directly toggle the NDEF Push feature, but they can request Settings UI allowing the user to toggle NDEF Push using startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS))

Example usage in an Activity that requires NDEF Push:

 protected void onResume() {
     super.onResume();
     if (!nfcAdapter.isEnabled()) {
         startActivity(new Intent(Settings.ACTION_NFC_SETTINGS));
     } else if (!nfcAdapter.isNdefPushEnabled()) {
         startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS));
     }
 }

setBeamPushUris

void setBeamPushUris (Uri[] uris, 
                Activity activity)

Set one or more Uris to send using Android Beam (TM). Every Uri you provide must have either scheme 'file' or scheme 'content'.

For the data provided through this method, Android Beam tries to switch to alternate transports such as Bluetooth to achieve a fast transfer speed. Hence this method is very suitable for transferring large files such as pictures or songs.

The receiving side will store the content of each Uri in a file and present a notification to the user to open the file with a Intent with action ACTION_VIEW. If multiple URIs are sent, the Intent will refer to the first of the stored files.

This method may be called at any time before onDestroy(), but the URI(s) are only made available for Android Beam when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's onCreate(Bundle) - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread.

setBeamPushUris(Uri[], Activity) and setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity) have priority over both setNdefPushMessage(NdefMessage, Activity, Activity...) and setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...).

If setBeamPushUris(Uri[], Activity) is called with a null Uri array, and/or setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity) is called with a null callback, then the Uri push will be completely disabled for the specified activity(s).

Code example:

 protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     if (nfcAdapter == null) return;  // NFC not available on this device
     nfcAdapter.setBeamPushUris(new Uri[] {uri1, uri2}, this);
 }

If your Activity wants to dynamically supply Uri(s), then set a callback using setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity) instead of using this method.

Do not pass in an Activity that has already been through onDestroy(). This is guaranteed if you call this API during onCreate(Bundle).

If this device does not support alternate transports such as Bluetooth or WiFI, calling this method does nothing.

Requires the NFC permission.

setBeamPushUrisCallback

void setBeamPushUrisCallback (NfcAdapter.CreateBeamUrisCallback callback, 
                Activity activity)

Set a callback that will dynamically generate one or more Uris to send using Android Beam (TM). Every Uri the callback provides must have either scheme 'file' or scheme 'content'.

For the data provided through this callback, Android Beam tries to switch to alternate transports such as Bluetooth to achieve a fast transfer speed. Hence this method is very suitable for transferring large files such as pictures or songs.

The receiving side will store the content of each Uri in a file and present a notification to the user to open the file with a Intent with action ACTION_VIEW. If multiple URIs are sent, the Intent will refer to the first of the stored files.

This method may be called at any time before onDestroy(), but the URI(s) are only made available for Android Beam when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's onCreate(Bundle) - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread.

setBeamPushUris(Uri[], Activity) and setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity) have priority over both setNdefPushMessage(NdefMessage, Activity, Activity...) and setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...).

If setBeamPushUris(Uri[], Activity) is called with a null Uri array, and/or setBeamPushUrisCallback(NfcAdapter.CreateBeamUrisCallback, Activity) is called with a null callback, then the Uri push will be completely disabled for the specified activity(s).

Code example:

 protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     if (nfcAdapter == null) return;  // NFC not available on this device
     nfcAdapter.setBeamPushUrisCallback(callback, this);
 }

Do not pass in an Activity that has already been through onDestroy(). This is guaranteed if you call this API during onCreate(Bundle).

If this device does not support alternate transports such as Bluetooth or WiFI, calling this method does nothing.

Requires the NFC permission.

setNdefPushMessage

void setNdefPushMessage (NdefMessage message, 
                Activity activity, 
                Activity... activities)

Set a static NdefMessage to send using Android Beam (TM).

This method may be called at any time before onDestroy(), but the NDEF message is only made available for NDEF push when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's onCreate(Bundle) - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread.

Only one NDEF message can be pushed by the currently resumed activity. If both setNdefPushMessage(NdefMessage, Activity, Activity...) and setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) are set, then the callback will take priority.

If neither setNdefPushMessage(NdefMessage, Activity, Activity...) or setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) have been called for your activity, then the Android OS may choose to send a default NDEF message on your behalf, such as a URI for your application.

If setNdefPushMessage(NdefMessage, Activity, Activity...) is called with a null NDEF message, and/or setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) is called with a null callback, then NDEF push will be completely disabled for the specified activity(s). This also disables any default NDEF message the Android OS would have otherwise sent on your behalf for those activity(s).

If you want to prevent the Android OS from sending default NDEF messages completely (for all activities), you can include a <meta-data> element inside the <application> element of your AndroidManifest.xml file, like this:

 <application ...>
     <meta-data android:name="android.nfc.disable_beam_default"
         android:value="true" />
 </application>

The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's onCreate(Bundle). For example:

 protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     if (nfcAdapter == null) return;  // NFC not available on this device
     nfcAdapter.setNdefPushMessage(ndefMessage, this);
 }

If your Activity wants to dynamically generate an NDEF message, then set a callback using setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) instead of a static message.

Do not pass in an Activity that has already been through onDestroy(). This is guaranteed if you call this API during onCreate(Bundle).

For sending large content such as pictures and songs, consider using setBeamPushUris(Uri[], Activity), which switches to alternate transports such as Bluetooth to achieve a fast transfer rate.

Requires the NFC permission.

setNdefPushMessageCallback

void setNdefPushMessageCallback (NfcAdapter.CreateNdefMessageCallback callback, 
                Activity activity, 
                Activity... activities)

Set a callback that dynamically generates NDEF messages to send using Android Beam (TM).

This method may be called at any time before onDestroy(), but the NDEF message callback can only occur when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's onCreate(Bundle) - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread.

Only one NDEF message can be pushed by the currently resumed activity. If both setNdefPushMessage(NdefMessage, Activity, Activity...) and setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) are set, then the callback will take priority.

If neither setNdefPushMessage(NdefMessage, Activity, Activity...) or setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) have been called for your activity, then the Android OS may choose to send a default NDEF message on your behalf, such as a URI for your application.

If setNdefPushMessage(NdefMessage, Activity, Activity...) is called with a null NDEF message, and/or setNdefPushMessageCallback(NfcAdapter.CreateNdefMessageCallback, Activity, Activity...) is called with a null callback, then NDEF push will be completely disabled for the specified activity(s). This also disables any default NDEF message the Android OS would have otherwise sent on your behalf for those activity(s).

If you want to prevent the Android OS from sending default NDEF messages completely (for all activities), you can include a <meta-data> element inside the <application> element of your AndroidManifest.xml file, like this:

 <application ...>
     <meta-data android:name="android.nfc.disable_beam_default"
         android:value="true" />
 </application>

The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's onCreate(Bundle). For example:

 protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     if (nfcAdapter == null) return;  // NFC not available on this device
     nfcAdapter.setNdefPushMessageCallback(callback, this);
 }

Do not pass in an Activity that has already been through onDestroy(). This is guaranteed if you call this API during onCreate(Bundle).

For sending large content such as pictures and songs, consider using setBeamPushUris(Uri[], Activity), which switches to alternate transports such as Bluetooth to achieve a fast transfer rate.

Requires the NFC permission.

setOnNdefPushCompleteCallback

void setOnNdefPushCompleteCallback (NfcAdapter.OnNdefPushCompleteCallback callback, 
                Activity activity, 
                Activity... activities)

Set a callback on successful Android Beam (TM).

This method may be called at any time before onDestroy(), but the callback can only occur when the specified activity(s) are in resumed (foreground) state. The recommended approach is to call this method during your Activity's onCreate(Bundle) - see sample code below. This method does not immediately perform any I/O or blocking work, so is safe to call on your main thread.

The API allows for multiple activities to be specified at a time, but it is strongly recommended to just register one at a time, and to do so during the activity's onCreate(Bundle). For example:

 protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
     if (nfcAdapter == null) return;  // NFC not available on this device
     nfcAdapter.setOnNdefPushCompleteCallback(callback, this);
 }

Do not pass in an Activity that has already been through onDestroy(). This is guaranteed if you call this API during onCreate(Bundle).

Requires the NFC permission.