Merge "cherrypick from master - docs: nfc updates Change-Id: Iaa782911f14b11bc896ac9ef06db2c43104d1dac" into ics-mr0
diff --git a/docs/html/guide/guide_toc.cs b/docs/html/guide/guide_toc.cs
index f3540e2..b7710c3 100644
--- a/docs/html/guide/guide_toc.cs
+++ b/docs/html/guide/guide_toc.cs
@@ -262,20 +262,20 @@
</ul>
</li>
<li class="toggle-list">
- <div><a href="<?cs var:toroot ?>guide/topics/renderscript/index.html">
- <span class="en">RenderScript</span>
- </a></div>
- <ul>
- <li><a href="<?cs var:toroot ?>guide/topics/renderscript/graphics.html">
- <span class="en">Graphics</span>
- </a>
- </li>
- <li><a href="<?cs var:toroot ?>guide/topics/renderscript/compute.html">
- <span class="en">Compute</span>
- </a>
- </li>
- </ul>
- </li>
+ <div><a href="<?cs var:toroot ?>guide/topics/renderscript/index.html">
+ <span class="en">RenderScript</span></a>
+ </div>
+ <ul>
+ <li><a href="<?cs var:toroot ?>guide/topics/renderscript/graphics.html">
+ <span class="en">Graphics</span>
+ </a>
+ </li>
+ <li><a href="<?cs var:toroot ?>guide/topics/renderscript/compute.html">
+ <span class="en">Compute</span>
+ </a>
+ </li>
+ </ul>
+ </li>
<li class="toggle-list">
<div><a href="<?cs var:toroot ?>guide/topics/media/index.html">
@@ -332,9 +332,15 @@
<li><a href="<?cs var:toroot?>guide/topics/wireless/bluetooth.html">
<span class="en">Bluetooth</span></a>
</li>
- <li><a href="<?cs var:toroot?>guide/topics/nfc/index.html">
- <span class="en">Near Field Communication</span>
- </a></li>
+ <li class="toggle-list">
+ <div><a href="<?cs var:toroot?>guide/topics/nfc/index.html">
+ <span class="en">Near Field Communication</span></a> <span class="new">updated</span>
+ </div>
+ <ul>
+ <li><a href="<?cs var:toroot ?>guide/topics/nfc/nfc.html">NFC Basics</a></li>
+ <li><a href="<?cs var:toroot ?>guide/topics/nfc/advanced-nfc.html">Advanced NFC</a></li>
+ </ul>
+ </li>
<li class="toggle-list">
<div><a href="<?cs var:toroot?>guide/topics/usb/index.html">
<span class="en">USB</span></a>
@@ -715,7 +721,7 @@
<li class="toggle-list">
<div><a href="<?cs var:toroot ?>guide/practices/ui_guidelines/index.html">
<span class="en">UI Guidelines</span>
- </a></div>
+ </a> <span class="new-child">updated</span></div>
<ul>
<li class="toggle-list">
<div><a href="<?cs var:toroot ?>guide/practices/ui_guidelines/icon_design.html">
diff --git a/docs/html/guide/topics/nfc/advanced-nfc.jd b/docs/html/guide/topics/nfc/advanced-nfc.jd
new file mode 100644
index 0000000..2b414aa
--- /dev/null
+++ b/docs/html/guide/topics/nfc/advanced-nfc.jd
@@ -0,0 +1,303 @@
+page.title=Advanced NFC
+@jd:body
+
+<div id="qv-wrapper">
+<div id="qv">
+ <h2>In this document</h2>
+ <ol>
+ <li><a href="#tag-tech">Working with Supported Tag Technologies</a>
+ <ol>
+ <li><a href="#tech-intent">Working with tag technologies and the ACTION_TECH_DISCOVERED
+ intent</a></li>
+ <li><a href="#read-write">Reading and writing to tags</a></li>
+ </ol></li>
+ <li><a href="#foreground-dispatch">Using the Foreground Dispatch System</a></li>
+ </ol>
+</div>
+</div>
+
+<p>This document describes advanced NFC topics, such as working with various tag technologies,
+writing to NFC tags, and foreground dispatching, which allows an application in the foreground to
+handle intents even when other applications filter for the same ones.</p>
+
+<h2 id="tag-tech">Working with Supported Tag Technologies</h2>
+<p>When working with NFC tags and Android-powered devices, the main format you use to read
+and write data on tags is NDEF. When a device scans a tag with NDEF data, Android provides support
+in parsing the message and delivering it in an {@link android.nfc.NdefMessage} when
+possible. There are cases, however, when you scan a tag that does not contain
+NDEF data or when the NDEF data could not be mapped to a MIME type or URI.
+In these cases, you need to open communication directly with the tag and read and write to it with
+your own protocol (in raw bytes). Android provides generic support for these use cases with the
+{@link android.nfc.tech} package, which is described in <a href="#tech-table">Table 1</a>. You can
+use the {@link android.nfc.Tag#getTechList getTechList()} method to determine the technologies
+supported by the tag and create the corresponding {@link android.nfc.tech.TagTechnology}
+object with one of classes provided by {@link android.nfc.tech} </p>
+
+
+<table>
+
+<p class="table-caption" id="table1">
+<strong>Table 1.</strong> Supported tag technologies</p>
+<table id="tech-table">
+
+ <tr>
+ <th>Class</th>
+
+ <th>Description</th>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.TagTechnology}</td>
+
+ <td>The interface that all tag technology classes must implement.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.NfcA}</td>
+
+ <td>Provides access to NFC-A (ISO 14443-3A) properties and I/O operations.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.NfcB}</td>
+
+ <td>Provides access to NFC-B (ISO 14443-3B) properties and I/O operations.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.NfcF}</td>
+
+ <td>Provides access to NFC-F (JIS 6319-4) properties and I/O operations.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.NfcV}</td>
+
+ <td>Provides access to NFC-V (ISO 15693) properties and I/O operations.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.IsoDep}</td>
+
+ <td>Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.Ndef}</td>
+
+ <td>Provides access to NDEF data and operations on NFC tags that have been formatted as
+ NDEF.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.NdefFormatable}</td>
+
+ <td>Provides a format operations for tags that may be NDEF formattable.</td>
+ </tr>
+ </table>
+<p>The following tag technlogies are not required to be supported by Android-powered devices.</p>
+ <p class="table-caption" id="table2">
+<strong>Table 2.</strong> Optional supported tag technologies</p>
+ <table>
+ <tr>
+ <th>Class</th>
+
+ <th>Description</th>
+ </tr>
+ <tr>
+ <td>{@link android.nfc.tech.MifareClassic}</td>
+
+ <td>Provides access to MIFARE Classic properties and I/O operations, if this Android device
+ supports MIFARE.</td>
+ </tr>
+
+ <tr>
+ <td>{@link android.nfc.tech.MifareUltralight}</td>
+
+ <td>Provides access to MIFARE Ultralight properties and I/O operations, if this Android
+ device supports MIFARE.</td>
+ </tr>
+ </table>
+
+<h3 id="tech-intent">Working with tag technologies and the ACTION_TECH_DISCOVERED intent</h3>
+<p>When a device scans a tag that has NDEF data on it, but could not be mapped to a MIME or URI,
+the tag dispatch system tries to start an activity with the {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}
+intent. The {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} is also used when a tag
+with non-NDEF data is scanned. Having this fallback allows you to work with the data on the tag
+directly if the tag dispatch system could not parse it for you. The basic steps when working with
+tag technologies are as follows:</p>
+
+<ol>
+ <li>Filter for an {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent specifying the
+tag technologies that you want to handle. See <a
+href="{@docRoot}guide/topics/nfc/nfc.html#tech-disc">Filtering for NFC
+intents</a> for more information. In general, the tag dispatch system tries to start a {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent when an NDEF message
+cannot be mapped to a MIME type or URI, or if the tag scanned did not contain NDEF data. For
+more information on how this is determined, see <a
+href="{@docRoot}guide/topics/nfc/nfc.html#tag-dispatch">The Tag Dispatch System</a>.</li>
+ <li>When your application receives the intent, obtain the {@link android.nfc.Tag} object from
+the intent:
+<pre>Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);</pre></li>
+<li>Obtain an instance of a {@link android.nfc.tech.TagTechnology}, by calling one of the
+<code>get</code> factory methods of the classes in the {@link android.nfc.tech} package. You can
+enumerate the supported technologies of the tag by calling {@link android.nfc.Tag#getTechList
+getTechList()} before calling a <code>get</code> factory method. For example, to obtain an instance
+of {@link android.nfc.tech.MifareUltralight} from a {@link android.nfc.Tag}, do the following:
+
+<pre>
+MifareUltralight.get(intent.getParcelableExtra(NfcAdapter.EXTRA_TAG));
+</pre>
+</li>
+</ol>
+
+
+
+<h3 id="read-write">Reading and writing to tags</h3>
+
+<p>Reading and writing to an NFC tag involves obtaining the tag from the intent and
+opening communication with the tag. You must define your own protocol stack to read and write data
+to the tag. Keep in mind, however, that you can still read and write NDEF data when working
+directly with a tag. It is up to you how you want to structure things. The
+following example shows how to work with a MIFARE Ultralight tag.</p>
+
+<pre>
+package com.example.android.nfc;
+
+import android.nfc.Tag;
+import android.nfc.tech.MifareUltralight;
+import android.util.Log;
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+public class MifareUltralightTagTester {
+
+ private static final String TAG = MifareUltralightTagTester.class.getSimpleName();
+
+ public void writeTag(Tag tag, String tagText) {
+ MifareUltralight ultralight = MifareUltralight.get(tag);
+ try {
+ ultralight.connect();
+ ultralight.writePage(4, "abcd".getBytes(Charset.forName("US-ASCII")));
+ ultralight.writePage(5, "efgh".getBytes(Charset.forName("US-ASCII")));
+ ultralight.writePage(6, "ijkl".getBytes(Charset.forName("US-ASCII")));
+ ultralight.writePage(7, "mnop".getBytes(Charset.forName("US-ASCII")));
+ } catch (IOException e) {
+ Log.e(TAG, "IOException while closing MifareUltralight...", e);
+ } finally {
+ try {
+ ultralight.close();
+ } catch (IOException e) {
+ Log.e(TAG, "IOException while closing MifareUltralight...", e);
+ }
+ }
+ }
+
+ public String readTag(Tag tag) {
+ MifareUltralight mifare = MifareUltralight.get(tag);
+ try {
+ mifare.connect();
+ byte[] payload = mifare.readPages(4);
+ return new String(payload, Charset.forName("US-ASCII"));
+ } catch (IOException e) {
+ Log.e(TAG, "IOException while writing MifareUltralight
+ message...", e);
+ } finally {
+ if (mifare != null) {
+ try {
+ mifare.close();
+ }
+ catch (IOException e) {
+ Log.e(TAG, "Error closing tag...", e);
+ }
+ }
+ }
+ return null;
+ }
+}
+</pre>
+
+</pre>
+
+ <h2 id="foreground-dispatch">Using the Foreground Dispatch System</h2>
+
+ <p>The foreground dispatch system allows an activity to intercept an intent and claim
+priority over other activities that handle the same intent. Using this system involves
+ constructing a few data structures for the Android system to be able to send the appropriate
+ intents to your application. To enable the foreground dispatch system:</p>
+
+ <ol>
+ <li>Add the following code in the <code>onCreate()</code> method of your activity:
+
+ <ol type="a">
+ <li>Create a {@link android.app.PendingIntent} object so the Android system can populate it
+ with the details of the tag when it is scanned.
+ <pre>
+PendingIntent pendingIntent = PendingIntent.getActivity(
+ this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
+</pre>
+ </li>
+
+ <li>Declare intent filters to handle the intents that you want to intercept. The foreground
+ dispatch system checks the specified intent filters with the intent that is received when
+ the device scans a tag. If it matches, then your application handles the intent. If it does
+ not match, the foreground dispatch system falls back to the intent dispatch system.
+ Specifying a <code>null</code> array of intent filters and technology filters, specifies
+ that you want to filter for all tags that fallback to the <code>TAG_DISCOVERED</code>
+ intent. The code snippet below handles all MIME types for <code>NDEF_DISCOVERED</code>. You
+ should only handle the ones that you need.
+<pre>
+IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
+ try {
+ ndef.addDataType("*/*"); /* Handles all MIME based dispatches.
+ You should specify only the ones that you need. */
+ }
+ catch (MalformedMimeTypeException e) {
+ throw new RuntimeException("fail", e);
+ }
+ intentFiltersArray = new IntentFilter[] {ndef, };
+</pre>
+ </li>
+
+ <li>Set up an array of tag technologies that your application wants to handle. Call the
+ <code>Object.class.getName()</code> method to obtain the class of the technology that you
+ want to support.
+<pre>
+techListsArray = new String[][] { new String[] { NfcF.class.getName() } };
+</pre>
+ </li>
+ </ol>
+ </li>
+
+ <li>Override the following activity lifecycle callbacks and add logic to enable and disable the
+ foreground dispatch when the activity loses ({@link android.app.Activity#onPause onPause()})
+ and regains ({@link android.app.Activity#onResume onResume()}) focus. {@link
+ android.nfc.NfcAdapter#enableForegroundDispatch enableForegroundDispatch()} must be called from
+the main thread and only when the activity is in the foreground (calling in {@link
+android.app.Activity#onResume onResume()} guarantees this). You also need to implement the {@link
+ android.app.Activity#onNewIntent onNewIntent} callback to process the data from the scanned NFC
+ tag.</li>
+
+<pre>
+public void onPause() {
+ super.onPause();
+ mAdapter.disableForegroundDispatch(this);
+}
+
+public void onResume() {
+ super.onResume();
+ mAdapter.enableForegroundDispatch(this, pendingIntent, intentFiltersArray, techListsArray);
+}
+
+public void onNewIntent(Intent intent) {
+ Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
+ //do something with tagFromIntent
+}
+</pre>
+ </li>
+ </ol>
+
+ <p>See the <a href=
+"{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundDispatch.html">
+ForegroundDispatch</a> sample from API Demos for the complete sample.</p>
\ No newline at end of file
diff --git a/docs/html/guide/topics/nfc/index.jd b/docs/html/guide/topics/nfc/index.jd
index b486d3b..b86d72d 100644
--- a/docs/html/guide/topics/nfc/index.jd
+++ b/docs/html/guide/topics/nfc/index.jd
@@ -1,601 +1,33 @@
page.title=Near Field Communication
@jd:body
-<div id="qv-wrapper">
-<div id="qv">
- <h2>In this document</h2>
- <ol>
- <li><a href="#api">API Overview</a></li>
- <li><a href="#manifest">Declaring Android Manifest elements</a></li>
- <li><a href="#dispatch">The Tag Dispatch System</a>
- <ol>
- <li><a href="#intent-dispatch">Using the intent dispatch system</a></li>
- <li><a href="#foreground-dispatch">Using the foreground dispatch system</a></li>
- </ol></li>
- <li><a href="#ndef">Working with Data on NFC Tags</a></li>
- <li><a href="#read">Reading an NFC Tag</a></li>
- <li><a href="#write">Writing to an NFC Tag</a></li>
- <li><a href="#p2p">Peer-to-Peer Data Exchange</a></li>
- </ol>
-</div>
-</div>
-
<p>Near Field Communication (NFC) is a set of short-range wireless technologies, typically
- requiring a distance of 4cm or less. NFC operates at 13.56mhz, and at rates ranging from 106
- kbit/s to 848 kbit/s. NFC communication always involves an initiator and a target. The initiator
- actively generates an RF field that can power a passive target. This enables NFC targets to take
- very simple form factors such as tags, stickers or cards that do not require power. NFC
- peer-to-peer communication is also possible, where both devices are powered.</p>
+ requiring a distance of 4cm or less to initiate a connection. NFC allows you to share small
+ payloads of data between an NFC tag and an Android-powered device, or between two Android-powered
+ devices.
- <p>Compared to other wireless technologies such as Bluetooth or WiFi, NFC provides much lower
- bandwidth and range, but enables low-cost, un-powered targets and does not require discovery or
- pairing. Interactions can be initiated with just a tap.</p>
-
- <p>An Android device with NFC hardware will typically act as an initiator when the screen is on.
- This mode is also known as NFC reader/writer. It will actively look for NFC tags and start
- activities to handle them. Android 2.3.3 also has some limited P2P support.</p>
-
- <p>Tags can range in complexity, simple tags just offer read/write semantics, sometimes with
+ <p>Tags can range in complexity. Simple tags offer just read and write semantics, sometimes with
one-time-programmable areas to make the card read-only. More complex tags offer math operations,
and have cryptographic hardware to authenticate access to a sector. The most sophisticated tags
- contain operating environments, allowing complex interactions with code executing on the tag.</p>
+ contain operating environments, allowing complex interactions with code executing on the tag.
+ The data stored in the tag can also be written in a variety of formats, but many of the Android
+ framework APIs are based around a <a href="http://www.nfc-forum.org/">NFC Forum</a> standard
+ called NDEF (NFC Data Exchange Format).</p>
- <h2 id="api">API Overview</h2>
+ <dl>
+ <dt><strong><a href="{@docRoot}guide/topics/nfc/nfc.html">NFC Basics</a></strong></dt>
+ <dd>This document describes how Android handles discovered NFC tags and how it notifies
+applications of data that is relevant to the application. It also goes over how to work with the
+NDEF data in your applications and gives an overview of the framework APIs that support the basic
+NFC feature set of Android.</dd>
- <p>The {@link android.nfc} package contains the high-level classes to interact with the local
- device's NFC adapter, to represent discovered tags, and to use the NDEF data format.</p>
-
- <table>
- <tr>
- <th>Class</th>
-
- <th>Description</th>
- </tr>
-
- <tr>
- <td>{@link android.nfc.NfcManager}</td>
-
- <td>A high level manager class that enumerates the NFC adapters on this Android device. Since
- most Android devices only have one NFC adapter, you can just use the static helper {@link
- android.nfc.NfcAdapter#getDefaultAdapter(Context)} for most situations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.NfcAdapter}</td>
-
- <td>Represents the local NFC adapter. Defines the intent's used to request tag dispatch to
- your activity, and provides methods to register for foreground tag dispatch and foreground
- NDEF push. Foreground NDEF push is the only peer-to-peer support that is currently provided
- in Android.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.NdefMessage} and {@link android.nfc.NdefRecord}</td>
-
- <td>NDEF is an NFC Forum defined data structure, designed to efficiently store data on NFC
- tags, such as text, URL's, and other MIME types. A {@link android.nfc.NdefMessage} acts as a
- container for the data that you want to transmit or read. One {@link android.nfc.NdefMessage}
- object contains zero or more {@link android.nfc.NdefRecord}s. Each NDEF record has a type
- such as text, URL, smart poster, or any MIME data. The type of the first NDEF record in the
- NDEF message is used to dispatch a tag to an activity on Android.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.Tag}</td>
-
- <td>Represents a passive NFC target. These can come in many form factors such as a tag, card,
- key fob, or even a phone doing card emulation. When a tag is discovered, a {@link
- android.nfc.Tag} object is created and wrapped inside an Intent. The NFC dispatch system
- sends the intent to a compatible activity using <code>startActivity()</code>. You can use the
- {@link android.nfc.Tag#getTechList getTechList()} method to determine the technologies
- supported by this tag and create the corresponding {@link android.nfc.tech.TagTechnology}
- object with one of classes provided by {@link android.nfc.tech}.</td>
- </tr>
- </table>
-
- <p>The {@link android.nfc.tech} package contains classes to query properties and perform I/O
- operations on a tag. The classes are divided to represent different NFC technologies that can be
- available on a Tag:</p>
-
- <table>
- <tr>
- <th>Class</th>
-
- <th>Description</th>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.TagTechnology}</td>
-
- <td>The interface that all tag technology classes must implement.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.NfcA}</td>
-
- <td>Provides access to NFC-A (ISO 14443-3A) properties and I/O operations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.NfcB}</td>
-
- <td>Provides access to NFC-B (ISO 14443-3B) properties and I/O operations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.NfcF}</td>
-
- <td>Provides access to NFC-F (JIS 6319-4) properties and I/O operations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.NfcV}</td>
-
- <td>Provides access to NFC-V (ISO 15693) properties and I/O operations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.IsoDep}</td>
-
- <td>Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.Ndef}</td>
-
- <td>Provides access to NDEF data and operations on NFC tags that have been formatted as
- NDEF.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.NdefFormatable}</td>
-
- <td>Provides a format operations for tags that may be NDEF formattable.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.MifareClassic}</td>
-
- <td>Provides access to MIFARE Classic properties and I/O operations, if this Android device
- supports MIFARE.</td>
- </tr>
-
- <tr>
- <td>{@link android.nfc.tech.MifareUltralight}</td>
-
- <td>Provides access to MIFARE Ultralight properties and I/O operations, if this Android
- device supports MIFARE.</td>
- </tr>
- </table>
-
- <h2 id="manifest">Declaring Android Manifest elements</h2>
-
- <p>Before you can access a device's NFC hardware and properly handle NFC intents, declare these
- items in your <code>AndroidManifest.xml</code> file:</p>
-
- <ol>
- <li>The NFC <code><uses-permission></code> element to access the NFC hardware:
- <pre>
-<uses-permission android:name="android.permission.NFC" />
-</pre>
- </li>
-
- <li>The minimum SDK version that your application can support. API level 9 only supports
- limited tag dispatch via {@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED}, and only gives
- access to NDEF messages via the {@link android.nfc.NfcAdapter#EXTRA_NDEF_MESSAGES} extra. No
- other tag properties or I/O operations are accessible. You probably want to use API level 10
- which includes comprehensive reader/writer support.
- <pre class="pretty-print">
-<uses-sdk android:minSdkVersion="10"/>
-</pre>
- </li>
-
- <li>The uses-feature element so that your application can show up in the Android Market for
- devices that have NFC hardware:
- <pre>
-<uses-feature android:name="android.hardware.nfc" android:required="true" />
-</pre>
- </li>
-
- <li>The NFC intent filter to tell the Android system your Activity can handle NFC data. Specify
- one or more of these three intent filters:
- <pre>
-<intent-filter>
- <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
- <data android:mimeType="<em>mime/type</em>" />
-</intent-filter>
-
-<intent-filter>
- <action android:name="android.nfc.action.TECH_DISCOVERED"/>
- <meta-data android:name="android.nfc.action.TECH_DISCOVERED"
- android:resource="@xml/<em>nfc_tech_filter</em>.xml" />
-</intent-filter>
-
-<intent-filter>
- <action android:name="android.nfc.action.TAG_DISCOVERED"/>
-</intent-filter>
-</pre>
-
- <p>The three intent filters are prioritized and behave in specific ways. Declare only the
- ones that your Activity needs to handle. For more information on how to handle these filters,
- see the section about <a href="#dispatch">The Tag Dispatch System</a>.</p>
- </li>
- </ol>
-
- <p>View the <a href=
- "../../../resources/samples/NFCDemo/AndroidManifest.html">AndroidManifest.xml</a> from the
- NFCDemo sample to see a complete example.</p>
-
- <h2 id="dispatch">The Tag Dispatch System</h2>
-
- <p>When an Android device scans an NFC tag, the desired behavior is to have the most appropriate
- Activity handle the intent without asking the user what application to use. Because devices scan
- NFC tags at a very short range, it is likely that making users manually select an Activity forces
- them to move the device away from the tag and break the connection. You should develop your
- Activity to only handle the NFC tags that your Activity cares about to prevent the Activity
- Chooser from appearing. Android provides two systems to help you correctly identify an NFC tag
- that your Activity should handle: the Intent dispatch system and the foreground Activity dispatch
- system.</p>
-
- <p>The intent dispatch system checks the intent filters of all the Activities along with the
- types of data that the Activities support to find the best Activity that can handle the NFC tag.
- If multiple Activities specify the same intent filter and data to handle, then the Activity
- Chooser is presented to the user as a last resort.</p>
-
- <p>The foreground dispatch system allows an Activity application to override the intent dispatch
- system and have priority when an NFC tag is scanned. The Activity handling the request must be
- running in the foreground of the device. When an NFC tag is scanned and matches the intent and
- data type that the foreground dispatch Activity defines, the intent is immediately sent to the
- Activity even if another Activity can handle the intent. If the Activity cannot handle the
- intent, the foreground dispatch system falls back to the intent dispatch system.</p>
-
- <h3 id="intent-dispatch">Using the intent dispatch system</h3>
-
- <p>The intent dispatch system specifies three intents that each have a priority. The intents that
- start when a device scans a tag depend on the type of tag scanned. In general, the intents are
- started in the following manner:</p>
-
- <ul>
- <li>
- <code>android.nfc.action.NDEF_DISCOVERED</code>: This intent starts when a tag that contains
- an NDEF payload is scanned. This is the highest priority intent. The Android system does not
- let you specify this intent generically to handle all data types. You must specify
- <code><data></code> elements in the <code>AndroidManifest.xml</code> along with this
- intent to correctly handle NFC tags that start this intent. For example, to handle a
- <code>NDEF_DISCOVERED</code> intent that contains plain text, specify the following filter in
- your <code>AndroidManifest.xml</code> file:
- <pre>
-<intent-filter>
- <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
- <data android:mimeType="text/plain" />
-</intent-filter>
-</pre>
-
- <p>If the <code>NDEF_DISCOVERED</code> intent is started, the <code>TECH_DISCOVERED</code>
- and <code>TAG_DISCOVERED</code> intents are not started. This intent does not start if an
- unknown tag is scanned or if the tag does not contain an NDEF payload.</p>
- </li>
-
- <li><code>android.nfc.action.TECH_DISCOVERED</code>: If the <code>NDEF_DISCOVERED</code> intent
- does not start or is not filtered by any Activity on the device, this intent starts if the tag
- is known. The <code>TECH_DISCOVERED</code> intent requires that you specify the technologies
- that you want to support in an XML resource file. For more information, see the section about
- <a href="#technology-resources">Specifying tag technologies to handle</a>.</li>
-
- <li><code>android.nfc.action.TAG_DISCOVERED</code>: This intent starts if no Activities handle
- the <code>NDEF_DISCOVERED</code> and <code>TECH_DISCOVERED</code> intents or if the tag that is
- scanned is unknown.</li>
- </ul>
-
- <h4 id="tech">Specifying tag technologies to handle</h4>
-
- <p>If your Activity declares the <code>android.nfc.action.TECH_DISCOVERED</code> intent in your
- <code>AndroidManifest.xml</code> file, you must create an XML resource file that specifies the
- technologies that your Activity supports within a <code>tech-list</code> set. Your Activity is
- considered a match if a <code>tech-list</code> set is a subset of the technologies that are
- supported by the tag, which you can obtain by calling {@link android.nfc.Tag#getTechList
- getTechList()}.</p>
-
- <p>For example, if the tag that is scanned supports MifareClassic, NdefFormatable, and NfcA, your
- <code>tech-list</code> set must specify all three, two, or one of the technologies (and nothing
- else) in order for your Activity to be matched.</p>
-
- <p>The following sample defines all of the technologies. You can remove the ones that you do not
- need. Save this file (you can name it anything you wish) in the
- <code><project-root>/res/xml</code> folder.</p>
- <pre>
-<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
- <tech-list>
- <tech>android.nfc.tech.IsoDep</tech>
- <tech>android.nfc.tech.NfcA</tech>
- <tech>android.nfc.tech.NfcB</tech>
- <tech>android.nfc.tech.NfcF</tech>
- <tech>android.nfc.tech.NfcV</tech>
- <tech>android.nfc.tech.Ndef</tech>
- <tech>android.nfc.tech.NdefFormatable</tech>
- <tech>android.nfc.tech.MifareClassic</tech>
- <tech>android.nfc.tech.MifareUltralight</tech>
- </tech-list>
-</resources>
-</pre>
-
- <p>You can also specify multiple <code>tech-list</code> sets. Each of the <code>tech-list</code>
- sets is considered independently, and your Activity is considered a match if any single
- <code>tech-list</code> set is a subset of the technologies that are returned by {@link
- android.nfc.Tag#getTechList getTechList()}. This provides <code>AND</code> and <code>OR</code>
- semantics for matching technologies. The following example matches tags that can support the
- NfcA and Ndef technologies or can support the NfcB and Ndef technologies:</p>
- <pre>
-<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
- <tech-list>
- <tech>android.nfc.tech.NfcA</tech>
- <tech>android.nfc.tech.Ndef</tech>
- </tech-list>
-</resources>
-
-<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
- <tech-list>
- <tech>android.nfc.tech.NfcB</tech>
- <tech>android.nfc.tech.Ndef</tech>
- </tech-list>
-</resources>
-</pre>
-
- <p>In your <code>AndroidManifest.xml</code> file, specify the resource file that you just created
- in the <code><meta-data></code> element inside the <code><activity></code>
- element like in the following example:</p>
- <pre>
-<activity>
-...
-<intent-filter>
- <action android:name="android.nfc.action.TECH_DISCOVERED"/>
-</intent-filter>
-
-<meta-data android:name="android.nfc.action.TECH_DISCOVERED"
- android:resource="@xml/nfc_tech_filter" />
-...
-</activity>
-</pre>
-
- <h3 id="foreground-dispatch">Using the foreground dispatch system</h3>
-
- <p>The foreground dispatch system allows an Activity to intercept an intent and claim priority
- over other Activities that handle the same intent. The system is easy to use and involves
- constructing a few data structures for the Android system to be able to send the appropriate
- intents to your application. To enable the foreground dispatch system:</p>
-
- <ol>
- <li>Add the following code in the onCreate() method of your Activity:
-
- <ol type="a">
- <li>Create a {@link android.app.PendingIntent} object so the Android system can populate it
- with the details of the tag when it is scanned
- <pre>
-PendingIntent pendingIntent = PendingIntent.getActivity(
- this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
-</pre>
- </li>
-
- <li>Declare intent filters to handle the intents that you want to intercept. The foreground
- dispatch system checks the specified intent filters with the intent that is received when
- the device scans a tag. If they match, then your application handles the intent. If it does
- not match, the foreground dispatch system falls back to the intent dispatch system.
- Specifying a <code>null</code> array of intent filters and for the technology filters, you
- receive a <code>TAG_DISCOVERED</code> intent for all tags discovered. Note that the snippet
- below handles all MIME types. You should only handle the ones that you need.
- <pre>
- IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
- try {
- ndef.addDataType("*/*"); /* Handles all MIME based dispatches.
- You should specify only the ones that you need. */
- }
- catch (MalformedMimeTypeException e) {
- throw new RuntimeException("fail", e);
- }
- intentFiltersArray = new IntentFilter[] {
- ndef,
- };
-</pre>
- </li>
-
- <li>Set up an array of tag technologies that your application wants to handle. Call the
- <code>Object.class.getName()</code> method to obtain the class of the technology that you
- want to support.
- <pre>
-
- techListsArray = new String[][] { new String[] { NfcF.class.getName() } };
-
-</pre>
- </li>
- </ol>
- </li>
-
- <li>Override the following Activity lifecycle callbacks and add logic to enable and disable the
- foreground dispatch when the Activity loses ({@link android.app.Activity#onPause onPause()})
- and regains ({@link android.app.Activity#onResume onResume()}) focus. {@link
- android.nfc.NfcAdapter#enableForegroundDispatch} must be called from the main thread and only
- when the activity is in the foreground (calling in {@link android.app.Activity#onResume
- onResume()} guarantees this). You also need to implement the {@link
- android.app.Activity#onNewIntent onNewIntent} callback to process the data from the scanned NFC
- tag.
- <pre>
-public void onPause() {
- super.onPause();
- mAdapter.disableForegroundDispatch(this);
-}
-
-public void onResume() {
- super.onResume();
- mAdapter.enableForegroundDispatch(this, pendingIntent, intentFiltersArray, techListsArray);
-}
-
-public void onNewIntent(Intent intent) {
- Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
- //do something with tagFromIntent
-}
-</pre>
- </li>
- </ol>
-
- <p>See the <a href=
- "{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundDispatch.html">ForegroundDispatch</a>
- sample from API Demos for the complete sample.</p>
-
- <h2 id="ndef">Working with Data on NFC Tags</h2>
-
- <p>Data on NFC tags are encoded in raw bytes, so you must convert the bytes to something human
- readable if you are presenting the data to the user. When writing to NFC tags, you must write
- them in bytes as well. Android provides APIs to help write messages that conform to the NDEF
- standard, which was developed by the <a href="http://www.nfc-forum.org/specs/">NFC Forum</a> to
- standardized data on tags. Using this standard ensures that your data will be supported by all
- Android NFC devices if you are writing to tags. However, many tag technologies use their own
- standard for storing data and are supported by Android as well, but you have to implement your
- own protocol stack to read and write to these tags. You can find a full list of the supported
- technologies in {@link android.nfc.tech} and an overview of the technologies in the {@link
- android.nfc.tech.TagTechnology} interface. This section is a brief overview of how to work with
- NDEF messages in the context of the Android system. It is not meant to be a complete discussion
- of the NDEF specification, but highlights the main things that you need to be aware of when
- working with NDEF messages in Android.</p>
-
- <p>To facilitate working with NDEF messages, Android provides the {@link android.nfc.NdefRecord}
- and {@link android.nfc.NdefMessage} to encapsulate the raw bytes that represent NDEF messages. An
- {@link android.nfc.NdefMessage} is the container for zero or more {@link
- android.nfc.NdefRecord}s. Each {@link android.nfc.NdefRecord} has its own unique type name
- format, record type, and ID to distinguish them from other records within the same {@link
- android.nfc.NdefMessage}. You can store different types of records of varying length in a single
- {@link android.nfc.NdefMessage}. The size constraint of the NFC tag determines how big your
- {@link android.nfc.NdefMessage} can be.</p>
-
- <p>Tags that support the {@link android.nfc.tech.Ndef} and {@link
- android.nfc.tech.NdefFormatable} technologies return and accept {@link android.nfc.NdefMessage}
- objects as parameters for read and write operations. You need to create your own logic to read
- and write bytes for other tag technologies in {@link android.nfc.tech}.</p>
-
- <p>You can download technical specifications for different types of NDEF message standards, such
- as plain text and Smart Posters, at the <a href="http://www.nfc-forum.org/specs/">NFC Forum</a>
- website. The NFCDemo sample application also declares sample <a href=
- "{@docRoot}resources/samples/NFCDemo/src/com/example/android/nfc/simulator/MockNdefMessages.html">
- plain text and SmartPoster NDEF messages.</a></p>
-
- <h2 id="read">Reading an NFC Tag</h2>
-
- <p>When a device comes in proximity to an NFC tag, the appropriate intent is started on the
- device, notifying interested applications that a NFC tag was scanned. By previously declaring the
- appropriate intent filter in your <code>AndroidManifest.xml</code> file or using foreground
- dispatching, your application can request to handle the intent.</p>
-
- <p>The following method (slightly modified from the NFCDemo sample application), handles the
- <code>TAG_DISCOVERED</code> intent and iterates through an array obtained from the intent that
- contains the NDEF payload:</p>
- <pre>
-NdefMessage[] getNdefMessages(Intent intent) {
- // Parse the intent
- NdefMessage[] msgs = null;
- String action = intent.getAction();
- if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
- Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
- if (rawMsgs != null) {
- msgs = new NdefMessage[rawMsgs.length];
- for (int i = 0; i < rawMsgs.length; i++) {
- msgs[i] = (NdefMessage) rawMsgs[i];
- }
- }
- else {
- // Unknown tag type
- byte[] empty = new byte[] {};
- NdefRecord record = new NdefRecord(NdefRecord.TNF_UNKNOWN, empty, empty, empty);
- NdefMessage msg = new NdefMessage(new NdefRecord[] {record});
- msgs = new NdefMessage[] {msg};
- }
- }
- else {
- Log.e(TAG, "Unknown intent " + intent);
- finish();
- }
- return msgs;
-}
-</pre>
-
- <p>Keep in mind that the data that the device reads is in bytes, so you must implement your own
- logic if you need to present the data in a readable format to the user. The classes in
- <code>com.example.android.nfc.record</code> of the NFCDemo sample show you how to parse some
- common types of NDEF messages such as plain text or a SmartPoster.</p>
-
- <h2 id="write">Writing to an NFC Tag</h2>
-
- <p>Writing to an NFC tag involves constructing your NDEF message in bytes and using the
- appropriate tag technology for the tag that you are writing to. The following code sample shows
- you how to write a simple text message to a {@link android.nfc.tech.NdefFormatable} tag:</p>
- <pre>
-NdefFormatable tag = NdefFormatable.get(t);
-Locale locale = Locale.US;
-final byte[] langBytes = locale.getLanguage().getBytes(Charsets.US_ASCII);
-String text = "Tag, you're it!";
-final byte[] textBytes = text.getBytes(Charsets.UTF_8);
-final int utfBit = 0;
-final char status = (char) (utfBit + langBytes.length);
-final byte[] data = Bytes.concat(new byte[] {(byte) status}, langBytes, textBytes);
-NdefRecord record = NdefRecord(NdefRecord.TNF_WELL_KNOWN, NdefRecord.RTD_TEXT, new byte[0], data);
-try {
- NdefRecord[] records = {text};
- NdefMessage message = new NdefMessage(records);
- tag.connect();
- tag.format(message);
-}
-catch (Exception e){
- //do error handling
-}
-</pre>
-
- <h2 id="p2p">Peer-to-Peer Data Exchange</h2>
-
- <p>Support for simple peer-to-peer data exchange is supported by the foreground push feature,
- which is enabled with the {@link android.nfc.NfcAdapter#enableForegroundNdefPush} method. To use
- this feature:</p>
-
- <ul>
- <li>The Activity that is pushing the data must be in the foreground</li>
-
- <li>You must encapsulate the data that you are sending in an {@link android.nfc.NdefMessage}
- object</li>
-
- <li>The NFC device that is receiving the pushed data (the scanned device) must support the
- <code>com.android.npp</code> NDEF push protocol, which is optional for Android devices.</li>
- </ul>
-
- <p class="note">If your Activity enables the foreground push feature and is in the foreground,
- the standard intent dispatch system is disabled. However, if your Activity also enables
- foreground dispatching, then it can still scan tags that match the intent filters set in the
- foreground dispatching.</p>
-
- <p>To enable foreground dispatching:</p>
-
- <ol>
- <li>Create an NdefMessage that contains the NdefRecords that you want to push onto the other
- device.</li>
-
- <li>Implement the {@link android.app.Activity#onResume onResume()} and {@link
- android.app.Activity#onPause onPause()} callbacks in your Activity to appropriately handle the
- foreground pushing lifecycle. You must call {@link
- android.nfc.NfcAdapter#enableForegroundNdefPush} from the main thread and only when the
- activity is in the foreground (calling in {@link android.app.Activity#onResume onResume()}
- guarantees this).
- <pre>
-public void onResume() {
- super.onResume();
- if (mAdapter != null)
- mAdapter.enableForegroundNdefPush(this, myNdefMessage);
-}
-public void onPause() {
- super.onPause();
- if (mAdapter != null)
- mAdapter.disableForegroundNdefPush(this);
-}
-</pre>
- </li>
- </ol>
-
- <p>When the Activity is in the foreground, you can now tap the device to another device and push
- the data to it. See the <a href=
- "../../../resources/samples/ApiDemos/src/com/example/android/apis/nfc/ForegroundNdefPush.html">ForegroundNdefPush</a>
- sample in API Demos for a simple example of peer-to-peer data exchange.</p>
\ No newline at end of file
+ <dt><strong><a href="{@docRoot}guide/topics/nfc/advanced-nfc.html">Advanced
+ NFC</a></strong></dt>
+ <dd>This document goes over the APIs that enable use of the various tag technologies that
+ Android supports. When you are not working with NDEF data, or when you are working with NDEF
+ data that Android cannot fully understand, you have to manually read or write to the tag in raw
+ bytes using your own protocol stack. In these cases, Android provides support to detect
+ certain tag technologies and to open communication with the tag using your own protocol
+ stack.</dd>
+ </dl>
+</p>
\ No newline at end of file
diff --git a/docs/html/guide/topics/nfc/nfc.jd b/docs/html/guide/topics/nfc/nfc.jd
new file mode 100644
index 0000000..892e418
--- /dev/null
+++ b/docs/html/guide/topics/nfc/nfc.jd
@@ -0,0 +1,922 @@
+page.title=NFC Basics
+@jd:body
+
+
+<div id="qv-wrapper">
+<div id="qv">
+ <h2>In this document</h2>
+ <ol>
+ <li><a href="#tag-dispatch">The Tag Dispatch System</a>
+ <ol>
+ <li><a href="#ndef">How NFC tags are mapped to MIME types and URIs</a></li>
+ <li><a href="#dispatching">How NFC Tags are Dispatched to Applications</a></li>
+ </ol>
+ </li>
+ <li><a href="#filtering-intents">Filtering for Intents</a>
+ <ol>
+ <li><a href="#ndef-disc">ACTION_NDEF_DISCOVERED</a></li>
+ <li><a href="#tech-disc">ACTION_TECH_DISCOVERED</a></li>
+ <li><a href="#tag-disc">ACTION_TAG_DISCOVERED</a></li>
+ <li><a href="#obtain-info">Obtaining information from intents</a></li>
+ </ol>
+ </li>
+ <li><a href="#creating-records">Creating Common Types of NDEF Records</a>
+ <ol>
+ <li><a href="#abs-uri">TNF_ABSOLUTE_URI</a></li>
+ <li><a href="#mime">TNF_MIME_MEDIA</a></li>
+ <li><a href="#well-known-text">TNF_WELL_KNOWN with RTD_TEXT</a></li>
+ <li><a href="#well-known-uri">TNF_WELL_KNOWN with RTD_URI</a></li>
+ <li><a href="#ext-type">TNF_EXTERNAL_TYPE</a></li>
+ <li><a href="#aar">Android Application Records</a></li>
+ </ol>
+ </li>
+ <li><a href="#p2p">Beaming NDEF Messages to Other Devices</a></li>
+ </ol>
+</div>
+</div>
+
+<p>This document describes the basic NFC tasks you perform in Android. It explains how to send and
+receive NFC data in the form of NDEF messages and describes the Android framework APIs that support
+these features. For more advanced topics, including a discussion of working with non-NDEF data,
+see <a href="{@docRoot}guide/topics/nfc/advanced-nfc.html">Advanced NFC</a>.</p>
+
+
+<p>There are two major uses cases when working with NDEF data and Android:</p>
+
+<ul>
+ <li>Reading NDEF data from an NFC tag</li>
+ <li>Beaming NDEF messages from one device to another with <a href="#p2p">Android
+Beam™</a></li>
+</ul>
+
+
+<p>Reading NDEF data from an NFC tag is handled with the <a href="#tag-dispatch">tag dispatch
+system</a>, which analyzes discovered NFC tags, appropriately categorizes the data, and starts
+an application that is interested in the categorized data. An application that wants to handle the
+scanned NFC tag can <a href="#filtering-intents">declare an intent filter</a> and
+request to handle the data.</p>
+
+<p>The Android Beam™ feature allows a device to push an NDEF message onto
+another device by physically tapping the devices together. This interaction provides an easier way
+to send data than other wireless technologies like Bluetooth, because with NFC, no manual device
+discovery or pairing is required. The connection is automatically started when two devices come
+into range. Android Beam is available through a set of NFC APIs, so any application can transmit
+information between devices. For example, the Contacts, Browser, and YouTube applications use
+Android Beam to share contacts, web pages, and videos with other devices.
+</p>
+
+
+<h2 id="tag-dispatch">The Tag Dispatch System</h2>
+
+<p>Android-powered devices are usually looking for NFC tags when the screen
+is unlocked, unless NFC is disabled in the device's Settings menu.
+When an Android-powered device discovers an NFC tag, the desired behavior
+is to have the most appropriate activity handle the intent without asking the user what application
+to use. Because devices scan NFC tags at a very short range, it is likely that making users manually
+select an activity would force them to move the device away from the tag and break the connection.
+You should develop your activity to only handle the NFC tags that your activity cares about to
+prevent the Activity Chooser from appearing.</p>
+
+<p>To help you with this goal, Android provides a special tag dispatch system that analyzes scanned
+NFC tags, parses them, and tries to locate applications that are interested in the scanned data. It
+does this by:</p>
+
+<ol>
+ <li>Parsing the NFC tag and figuring out the MIME type or a URI that identifies the data payload
+ in the tag.</li>
+ <li>Encapsulating the MIME type or URI and the payload into an intent. These first two
+ steps are described in <a href="#ndef">How NFC tags are mapped to MIME types and URIs</a>.</li>
+ <li>Starts an activity based on the intent. This is described in
+ <a href="#dispatching">How NFC Tags are Dispatched to Applications</a>.</li>
+</ol>
+
+<h3 id="ndef">How NFC tags are mapped to MIME types and URIs</h3>
+<p>Before you begin writing your NFC applications, it is important to understand the different
+types of NFC tags, how the tag dispatch system parses NFC tags, and the special work that the tag
+dispatch system does when it detects an NDEF message. NFC tags come in a
+wide array of technologies and can also have data written to them in many different ways.
+Android has the most support for the NDEF standard, which is defined by the <a
+href="http://www.nfc-forum.org/home">NFC Forum</a>.
+</p>
+
+<p>NDEF data is encapsulated inside a message ({@link android.nfc.NdefMessage}) that contains one
+or more records ({@link android.nfc.NdefRecord}). Each NDEF record must be well-formed according to
+the specification of the type of record that you want to create. Android
+also supports other types of tags that do not contain NDEF data, which you can work with by using
+the classes in the {@link android.nfc.tech} package. To learn more
+about these technologies, see the <a href="{@docRoot}guide/topics/nfc/advanced-nfc.html">Advanced
+NFC</a> topic. Working with these other types of tags involves
+writing your own protocol stack to communicate with the tags, so we recommend using NDEF when
+possible for ease of development and maximum support for Android-powered devices.
+</p>
+
+<p class="note"><strong>Note:</strong>
+To download complete NDEF specifications, go to the <a
+href="http://www.nfc-forum.org/specs/spec_license">NFC Forum Specification Download</a> site and see
+<a href="#creating-records">Creating common types of NDEF records</a> for examples of how to
+construct NDEF records. </p>
+
+<p>Now that you have some background in NFC tags, the following sections describe in more detail how
+Android handles NDEF formatted tags. When an Android-powered device scans an NFC tag containing NDEF
+formatted data, it parses the message and tries to figure out the data's MIME type or identifying
+URI. To do this, the system reads the first {@link android.nfc.NdefRecord} inside the {@link
+android.nfc.NdefMessage} to determine how to interpret the entire NDEF message (an NDEF message can
+have multiple NDEF records). In a well-formed NDEF message, the first {@link android.nfc.NdefRecord}
+contains the following fields:
+<dl>
+ <dt><strong>3-bit TNF (Type Name Format)</strong></dt>
+ <dd>Indicates how to interpret the variable length type field. Valid values are described in
+described in <a href="#table1">Table 1</a>.</dd>
+
+ <dt><strong>Variable length type</strong></dt>
+ <dd>Describes the type of the record. If using {@link android.nfc.NdefRecord#TNF_WELL_KNOWN}, use
+this field to specify the Record Type Definition (RTD). Valid RTD values are described in <a
+href="#table2">Table 2</a>.</dd>
+
+<dt><strong>Variable length ID</strong></dt>
+<dd>A unique identifier for the record. This field is not used often, but
+if you need to uniquely identify a tag, you can create an ID for it.</dd>
+
+<dt><strong>Variable length payload</strong></dt>
+<dd>The actual data payload that you want to read or write. An NDEF
+message can contain multiple NDEF records, so don't assume the full payload is in the first NDEF
+record of the NDEF message.</dd>
+
+</dl>
+
+<p>The tag dispatch system uses the TNF and type fields to try to map a MIME type or URI to the
+NDEF message. If successful, it encapsulates that information inside of a {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} intent along with the actual payload. However, there
+are cases when the tag dispatch system cannot determine the type of data based on the first NDEF
+record. This happens when the NDEF data cannot be mapped to a MIME type or URI, or when the
+NFC tag does not contain NDEF data to begin with. In such cases, a {@link
+android.nfc.Tag} object that has information about the tag's technologies and the payload are
+encapsulated inside of a {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent instead.</p>
+
+<p>
+<a href="#table1">Table 1.</a> describes how the tag dispatch system maps TNF and type
+fields to MIME types or URIs. It also describes which TNFs cannot be mapped to a MIME type or URI.
+In these cases, the tag dispatch system falls back to
+{@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.
+
+<p>For example, if the tag dispatch system encounters a record of type {@link
+android.nfc.NdefRecord#TNF_ABSOLUTE_URI}, it maps the variable length type field of that record
+into a URI. The tag dispatch system encapsulates that URI in the data field of an {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} intent along with other information about the tag,
+such as the payload. On the other hand, if it encounters a record of type {@link
+android.nfc.NdefRecord#TNF_UNKNOWN}, it creates an intent that encapsulates the tag's technologies
+instead.</p>
+
+
+<p class="table-caption" id="table1">
+ <strong>Table 1.</strong> Supported TNFs and their mappings</p>
+<table id="mappings">
+ <tr>
+ <th>Type Name Format (TNF)</th>
+ <th>Mapping</th>
+ </tr>
+ <tr>
+ <td>{@link android.nfc.NdefRecord#TNF_ABSOLUTE_URI}</td>
+ <td>URI based on the type field.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_EMPTY}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_EXTERNAL_TYPE}</td>
+ <td>URI based on the URN in the type field. The URN is encoded into the NDEF type field in
+ a shortened form: <code><em><domain_name>:<service_name></em></code>.
+ Android maps this to a URI in the form:
+ <code>vnd.android.nfc://ext/<em><domain_name>:<service_name></em></code>.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_MIME_MEDIA}</td>
+ <td>MIME type based on the type field.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_UNCHANGED}</td>
+ <td>Invalid in the first record, so falls back to
+ {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_UNKNOWN}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#TNF_WELL_KNOWN}</td>
+ <td>MIME type or URI depending on the Record Type Definition (RTD), which you set in the
+type field. See <a href="#well_known">Table 2.</a> for more information on
+available RTDs and their mappings.</td>
+ </tr>
+</table>
+
+<p class="table-caption" id="table2">
+ <strong>Table 2.</strong> Supported RTDs for TNF_WELL_KNOWN and their
+mappings</p>
+<table id="well-known">
+ <tr>
+ <th>Record Type Definition (RTD)</th>
+ <th>Mapping</th>
+ </tr>
+ <tr>
+ <td>{@link android.nfc.NdefRecord#RTD_ALTERNATIVE_CARRIER}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_HANDOVER_CARRIER}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_HANDOVER_REQUEST}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_HANDOVER_SELECT}</td>
+ <td>Falls back to {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_SMART_POSTER}</td>
+ <td>URI based on parsing the payload.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_TEXT}</td>
+ <td>MIME type of <code>text/plain</code>.</td>
+ </tr>
+ <td>{@link android.nfc.NdefRecord#RTD_URI}</td>
+ <td>URI based on payload.</td>
+ </tr>
+</table>
+
+<h3 id="dispatching">How NFC Tags are Dispatched to Applications</h3>
+
+<p>When the tag dispatch system is done creating an intent that encapsulates the NFC tag and its
+identifying information, it sends the intent to an interested application that
+filters for the intent. If more than one application can handle the intent, the Activity Chooser
+is presented so the user can select the Activity. The tag dispatch system defines three intents,
+which are listed in order of highest to lowest priority:</p>
+
+<ol>
+ <li>
+ {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED}: This intent is used to start an
+Activity when a tag that contains an NDEF payload is scanned and is of a recognized type. This is
+the highest priority intent, and the tag dispatch system tries to start an Activity with this
+intent before any other intent, whenever possible.
+ </li>
+
+ <li>{@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}: If no activities register to
+handle the {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED}
+intent, the tag dispatch system tries to start an application with this intent. This
+intent is also directly started (without starting {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} first) if the tag that is scanned
+contains NDEF data that cannot be mapped to a MIME type or URI, or if the tag does not contain NDEF
+data but is of a known tag technology.
+</li>
+
+ <li>{@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED}: This intent is started
+ if no activities handle the {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} or {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}
+ intents.</li>
+ </ol>
+
+<p>The basic way the tag dispatch system works is as follows:</p>
+
+<ol>
+ <li>Try to start an Activity with the intent that was created by the tag dispatch system
+when parsing the NFC tag (either
+{@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} or {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}).</li>
+ <li>If no activities filter for that intent, try to start an Activity with the next
+ lowest priority intent (either {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} or {@link
+android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED}) until an application filters for the
+ intent or until the tag dispatch system tries all possible intents.</li>
+ <li>If no applications filter for any of the intents, do nothing.</li>
+</ol>
+
+<img src="{@docRoot}images/nfc_tag_dispatch.png" />
+
+<p class="figure"><strong>Figure 1. </strong> Tag Dispatch System</p>
+
+
+<p>Whenever possible, work with NDEF messages and the {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} intent, because it is the most specific out of
+the three. This intent allows you to start your application at a more appropriate time than the
+other two intents, giving the user a better experience.</p>
+
+<h2 id="manifest">Requesting NFC Access in the Android Manifest</h2>
+
+ <p>Before you can access a device's NFC hardware and properly handle NFC intents, declare these
+ items in your <code>AndroidManifest.xml</code> file:</p>
+
+ <ul>
+ <li>The NFC <code><uses-permission></code> element to access the NFC hardware:
+ <pre>
+<uses-permission android:name="android.permission.NFC" />
+</pre>
+ </li>
+
+ <li>The minimum SDK version that your application can support. API level 9 only supports
+ limited tag dispatch via {@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED}, and only gives
+ access to NDEF messages via the {@link android.nfc.NfcAdapter#EXTRA_NDEF_MESSAGES} extra. No
+ other tag properties or I/O operations are accessible. API level 10
+ includes comprehensive reader/writer support as well as foreground NDEF pushing, and API level
+ 14 provides an easier way to push NDEF messages to other devices with Android Beam and extra
+ convenience methods to create NDEF records.
+<pre class="pretty-print">
+<uses-sdk android:minSdkVersion="10"/>
+</pre>
+ </li>
+
+ <li>The <code>uses-feature</code> element so that your application shows up in the Android
+Market only for devices that have NFC hardware:
+ <pre>
+<uses-feature android:name="android.hardware.nfc" android:required="true" />
+</pre>
+<p>If your application uses NFC functionality, but that functionality is not crucial to your
+application, you can omit the <code>uses-feature</code> element and check for NFC avalailbility at
+runtime by checking to see if {@link android.nfc.NfcAdapter#getDefaultAdapter getDefaultAdapter()}
+is <code>null</code>.</p>
+ </li>
+ </ul>
+
+ <h2 id="filtering-intents">Filtering for NFC Intents</h2>
+
+ <p>To start your application when an NFC tag that you want to handle is scanned, your application
+can filter for one, two, or all three of the NFC intents in the Android manifest. However, you
+usually want to filter for the {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} intent for the
+most control of when your application starts. The {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent is a fallback for {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} when no applications filter for
+ {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} or for when the payload is not
+NDEF. Filtering for {@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED} is usually too general of a
+category to filter on. Many applications will filter for {@link
+android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} or {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} before {@link
+android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED}, so your application has a low probability of
+starting. {@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED} is only available as a last resort
+for applications to filter for in the cases where no other applications are installed to handle the
+{@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} or {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED}intent.</p>
+
+<p>Because NFC tag deployments vary and are many times not under your control, this is not always
+possible, which is why you can fallback to the other two intents when necessary. When you have
+control over the types of tags and data written, it is recommended that you use NDEF to format your
+tags. The following sections describe how to filter for each type of intent.</p>
+
+
+<h3 id="ndef-disc">ACTION_NDEF_DISCOVERED</h3>
+<p>
+To filter for {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED} intents, declare the
+intent filter along with the type of data that you want to filter for. The
+following example filters for {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED}
+intents with a MIME type of <code>text/plain</code>:
+</p>
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
+ <category android:name="android.intent.category.DEFAULT"/>
+ <data android:mimeType="text/plain" />
+</intent-filter>
+</pre>
+<p>The following example filters for a URI in the form of
+<code>http://developer.android.com/index.html</code>.
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
+ <category android:name="android.intent.category.DEFAULT"/>
+ <data android:scheme="http"
+ android:host="developer.android.com"
+ android:pathPrefix="/index.html" />
+</intent-filter>
+</pre>
+
+
+ <h3 id="tech-disc">ACTION_TECH_DISCOVERED</h3>
+
+ <p>If your activity filters for the {@link android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent,
+you must create an XML resource file that specifies the technologies that your activity supports
+within a <code>tech-list</code> set. Your activity is
+ considered a match if a <code>tech-list</code> set is a subset of the technologies that are
+ supported by the tag, which you can obtain by calling {@link android.nfc.Tag#getTechList
+ getTechList()}.</p>
+
+ <p>For example, if the tag that is scanned supports MifareClassic, NdefFormatable, and NfcA, your
+ <code>tech-list</code> set must specify all three, two, or one of the technologies (and nothing
+ else) in order for your activity to be matched.</p>
+
+ <p>The following sample defines all of the technologies. You can remove the ones that you do not
+ need. Save this file (you can name it anything you wish) in the
+ <code><project-root>/res/xml</code> folder.</p>
+ <pre>
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+ <tech-list>
+ <tech>android.nfc.tech.IsoDep</tech>
+ <tech>android.nfc.tech.NfcA</tech>
+ <tech>android.nfc.tech.NfcB</tech>
+ <tech>android.nfc.tech.NfcF</tech>
+ <tech>android.nfc.tech.NfcV</tech>
+ <tech>android.nfc.tech.Ndef</tech>
+ <tech>android.nfc.tech.NdefFormatable</tech>
+ <tech>android.nfc.tech.MifareClassic</tech>
+ <tech>android.nfc.tech.MifareUltralight</tech>
+ </tech-list>
+</resources>
+</pre>
+
+ <p>You can also specify multiple <code>tech-list</code> sets. Each of the <code>tech-list</code>
+ sets is considered independently, and your activity is considered a match if any single
+ <code>tech-list</code> set is a subset of the technologies that are returned by {@link
+ android.nfc.Tag#getTechList getTechList()}. This provides <code>AND</code> and <code>OR</code>
+ semantics for matching technologies. The following example matches tags that can support the
+ NfcA and Ndef technologies or can support the NfcB and Ndef technologies:</p>
+ <pre>
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+ <tech-list>
+ <tech>android.nfc.tech.NfcA</tech>
+ <tech>android.nfc.tech.Ndef</tech>
+ </tech-list>
+</resources>
+
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+ <tech-list>
+ <tech>android.nfc.tech.NfcB</tech>
+ <tech>android.nfc.tech.Ndef</tech>
+ </tech-list>
+</resources>
+</pre>
+
+ <p>In your <code>AndroidManifest.xml</code> file, specify the resource file that you just created
+ in the <code><meta-data></code> element inside the <code><activity></code>
+ element like in the following example:</p>
+ <pre>
+<activity>
+...
+<intent-filter>
+ <action android:name="android.nfc.action.TECH_DISCOVERED"/>
+</intent-filter>
+
+<meta-data android:name="android.nfc.action.TECH_DISCOVERED"
+ android:resource="@xml/nfc_tech_filter" />
+...
+</activity>
+</pre>
+
+<p>For more information about working with tag technologies and the {@link
+android.nfc.NfcAdapter#ACTION_TECH_DISCOVERED} intent, see <a
+href="{@docRoot}guide/topics/nfc/advanced-nfc.html#tag-tech">Working with Supported Tag
+Technologies</a> in the Advanced NFC document.</p>
+<h3 id="tag-disc">ACTION_TAG_DISCOVERED</h3>
+<p>To filter for {@link android.nfc.NfcAdapter#ACTION_TAG_DISCOVERED} use the following intent
+filter:</p>
+
+
+<pre><intent-filter>
+ <action android:name="android.nfc.action.TAG_DISCOVERED"/>
+</intent-filter>
+</pre>
+
+
+
+<h3 id="obtain-info">Obtaining information from intents</h3>
+
+<p>If an activity starts because of an NFC intent, you can obtain information about the scanned NFC
+tag from the intent. Intents can contain the following extras depending on the tag that was scanned:
+
+<ul>
+ <li>{@link android.nfc.NfcAdapter#EXTRA_TAG} (required): A {@link android.nfc.Tag} object
+representing the scanned tag.</li>
+ <li>{@link android.nfc.NfcAdapter#EXTRA_NDEF_MESSAGES} (optional): An array of NDEF messages
+parsed from the tag. This extra is mandatory on {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED
+intents.</li>
+ <li>{@link android.nfc.NfcAdapter#EXTRA_ID} (optional): The low-level ID of the tag.</li></ul>
+
+<p>To obtain these extras, check to see if your activity was launched with one of
+the NFC intents to ensure that a tag was scanned, and then obtain the extras out of the
+intent. The following example checks for the {@link android.nfc.NfcAdapter#ACTION_NDEF_DISCOVERED}
+intent and gets the NDEF messages from an intent extra.</p>
+
+<pre>
+public void onResume() {
+ super.onResume();
+ ...
+ if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
+ Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
+ if (rawMsgs != null) {
+ msgs = new NdefMessage[rawMsgs.length];
+ for (int i = 0; i < rawMsgs.length; i++) {
+ msgs[i] = (NdefMessage) rawMsgs[i];
+ }
+ }
+ }
+ //process the msgs array
+}
+</pre>
+
+<p>Alternatively, you can obtain a {@link android.nfc.Tag} object from the intent, which will
+contain the payload and allow you to enumerate the tag's technologies:</p>
+
+<pre>Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);</pre>
+
+
+<h2 id="creating-records">Creating Common Types of NDEF Records</h2>
+<p>This section describes how to create common types of NDEF records to help you when writing to
+NFC tags or sending data with Android Beam. It also describes how to create the corresponding
+intent filter for the record. All of these NDEF record examples should be in the first NDEF
+record of the NDEF message that you are writing to a tag or beaming.</p>
+
+<h3 id="abs-uri">TNF_ABSOLUTE_URI</h3>
+<p>Given the following {@link android.nfc.NdefRecord#TNF_ABSOLUTE_URI} NDEF record, which is
+stored as the first record inside of an {@link android.nfc.NdefMessage}:</p>
+
+<pre>
+NdefRecord uriRecord = new NdefRecord(
+ NdefRecord.TNF_ABSOLUTE_URI ,
+ "http://developer.android.com/index.html".getBytes(Charset.forName("US-ASCII")),
+ new byte[0], new byte[0]);
+</pre>
+
+<p>the intent filter would look like this:</p>
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+ <category android:name="android.intent.category.DEFAULT" />
+ <data android:scheme="http"
+ android:host="developer.android.com"
+ android:pathPrefix="/index.html" />
+</intent-filter>
+</pre>
+
+
+<h3 id="mime">TNF_MIME_MEDIA</h3>
+<p>Given the following {@link android.nfc.NdefRecord#TNF_MIME_MEDIA} NDEF record, which is stored as
+the first record inside
+of an {@link android.nfc.NdefMessage}:</p>
+<pre>
+NdefRecord mimeRecord = new NdefRecord(
+ NdefRecord.TNF_MIME_MEDIA ,
+ "application/com.example.android.beam".getBytes(Charset.forName("US-ASCII")),
+ new byte[0], "Beam me up, Android!".getBytes(Charset.forName("US-ASCII")));
+</pre>
+
+<p>the intent filter would look like this:</p>
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+ <category android:name="android.intent.category.DEFAULT" />
+ <data android:mimeType="application/com.example.android.beam" />
+</intent-filter>
+</pre>
+
+
+<h3 id="well-known-text">TNF_WELL_KNOWN with RTD_TEXT</h3>
+
+<p>Given the following {@link android.nfc.NdefRecord#TNF_WELL_KNOWN} NDEF record, which is stored as
+the first record inside of an {@link android.nfc.NdefMessage}:</p>
+<pre>
+public NdefRecord createTextRecord(String payload, Locale locale, boolean encodeInUtf8) {
+ byte[] langBytes = locale.getLanguage().getBytes(Charset.forName("US-ASCII"));
+ Charset utfEncoding = encodeInUtf8 ? Charset.forName("UTF-8") : Charset.forName("UTF-16");
+ byte[] textBytes = payload.getBytes(utfEncoding);
+ int utfBit = encodeInUtf8 ? 0 : (1 << 7);
+ char status = (char) (utfBit + langBytes.length);
+ byte[] data = new byte[1 + langBytes.length + textBytes.length];
+ data[0] = (byte) status;
+ System.arraycopy(langBytes, 0, data, 1, langBytes.length);
+ System.arraycopy(textBytes, 0, data, 1 + langBytes.length, textBytes.length);
+ NdefRecord record = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
+ NdefRecord.RTD_TEXT, new byte[0], data);
+ return record;
+}
+</pre>
+
+<p>the intent filter would look like this:</p>
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+ <category android:name="android.intent.category.DEFAULT" />
+ <data android:mimeType="text/plain" />
+</intent-filter>
+</pre>
+
+
+<h3 id="well-known-uri">TNF_WELL_KNOWN with RTD_URI</h3>
+
+<p>Given the following {@link android.nfc.NdefRecord#TNF_WELL_KNOWN} NDEF record, which is stored as
+the first record inside of an {@link android.nfc.NdefMessage}:</p>
+
+<pre>
+byte[] uriField = "example.com".getBytes(Charset.forName("US-ASCII"));
+byte[] payload = new byte[uriField.length + 1]; //add 1 for the URI Prefix
+byte payload[0] = 0x01; //prefixes http://www. to the URI
+System.arraycopy(uriField, 0, payload, 1, uriField.length); //appends URI to payload
+NdefRecord rtdUriRecord = new NdefRecord(
+ NdefRecord.TNF_WELL_KNOWN, NdefRecord.RTD_URI, new byte[0], payload);
+</pre>
+
+<p>the intent filter would look like this:</p>
+
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+ <category android:name="android.intent.category.DEFAULT" />
+ <data android:scheme="http"
+ android:host="example.com"
+ android:pathPrefix="" />
+</intent-filter>
+</pre>
+
+<h3 id="ext-type">TNF_EXTERNAL_TYPE</h3>
+<p>Given the following {@link android.nfc.NdefRecord#TNF_EXTERNAL_TYPE} NDEF record, which is stored
+as the first record inside of an {@link android.nfc.NdefMessage}:</p>
+
+<pre>
+byte[] payload;
+...
+NdefRecord mimeRecord = new NdefRecord(
+ NdefRecord.TNF_EXTERNAL_TYPE, "example.com:externalType", new byte[0], payload);
+</pre>
+
+<p>the intent filter would look like this:</p>
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED" />
+ <category android:name="android.intent.category.DEFAULT" />
+ <data android:scheme="vnd.android.nfc"
+ android:host="ext"
+ android:pathPrefix="/example.com:externalType"/>
+</intent-filter>
+</pre>
+
+
+<p>Use TNF_EXTERNAL_TYPE for more generic NFC tag deployments to better support both
+Android-powered and non-Android-powered devices.</p>
+
+<p class="note"><strong>Note</strong>: URNs for {@link
+android.nfc.NdefRecord#TNF_EXTERNAL_TYPE} have a canonical format of:
+<code>urn:nfc:ext:example.com:externalType</code>, however the NFC Forum RTD specification
+declares that the <code>urn:nfc:ext:</code> portion of the URN must be ommitted from the
+NDEF record. So all you need to provide is the domain (<code>example.com</code> in the example)
+and type (<code>externalType</code> in the example) separated by a colon.
+When dispatching TNF_EXTERNAL_TYPE, Android converts the <code>urn:nfc:ext:example.com:externalType</code> URN to a
+<code>vnd.android.nfc://ext/example.com:externalType</code> URI, which is what the intent filter in the example
+declares.</p>
+
+<h3 id="aar">Android Application Records</h3>
+
+<p>
+Introduced in Android 4.0 (API level 14), an Android Application Record (AAR) provides a stronger
+certainty that your application is started when an NFC tag is scanned. An AAR has the package name
+of an application embedded inside an NDEF record. You can add an AAR to any NDEF record of your NDEF message,
+because Android searches the entire NDEF message for AARs. If it finds an AAR, it starts the application based
+on the package name inside the AAR. If the application is not present on the device,
+Android Market is launched to download the application.</p>
+
+<p>AARs are useful if you want to prevent other applications from filtering for the same intent and
+potentially handling specific tags that you have deployed. AARs are only supported at the
+application level, because of the package name constraint, and not at the Activity level as with
+intent filtering. If you want to handle an intent at the Activity level, <a
+href="filtering-intents">use intent filters</a>.
+</p>
+
+
+
+<p>If a tag contains an AAR, the tag dispatch system dispatches in the following manner:</p>
+<ol>
+ <li>Try to start an Activity using an intent filter as normal. If the Activity that matches
+the intent also matches the AAR, start the Activity.</li>
+ <li>If the Activity that filters for the intent does not match the
+AAR, if multiple Activities can handle the intent, or if no Activity handles the intent, start the
+application specified by the AAR.</li>
+ <li>If no application can start with the AAR, go to the Android Market to download the
+application based on the AAR.</li>
+</ol>
+
+</p>
+
+<p class="note"><strong>Note:</strong> You can override AARs and the intent dispatch system with the <a
+href="{@docRoot}guide/topics/nfc/advanced-nfc.html#foreground-dispatch">foreground dispatch
+system</a>, which allows a foreground activity to have priority when an NFC tag is discovered.
+With this method, the activity must be in the foreground to
+override AARs and the intent dispatch system.</p>
+
+<p>If you still want to filter for scanned tags that do not contain an AAR, you can declare
+intent filters as normal. This is useful if your application is interested in other tags
+that do not contain an AAR. For example, maybe you want to guarantee that your application handles
+proprietary tags that you deploy as well as general tags deployed by third parties. Keep in mind
+that AARs are specific to Android 4.0 devices or later, so when deploying tags, you most likely want
+to use a combination of AARs and MIME types/URIs to support the widest range of devices. In
+addition, when you deploy NFC tags, think about how you want to write your NFC tags to enable
+support for the most devices (Android-powered and other devices). You can do this by
+defining a relatively unique MIME type or URI to make it easier for applications to distinguish.
+</p>
+
+<p>Android provides a simple API to create an AAR,
+{@link android.nfc.NdefRecord#createApplicationRecord createApplicationRecord()}. All you need to
+do is embed the AAR anywhere in your {@link android.nfc.NdefMessage}. You do not want
+to use the first record of your {@link android.nfc.NdefMessage}, unless the AAR is the only
+record in the {@link android.nfc.NdefMessage}. This is because the Android
+system checks the first record of an {@link android.nfc.NdefMessage} to determine the MIME type or
+URI of the tag, which is used to create an intent for applications to filter. The following code
+shows you how to create an AAR:</p>
+
+<pre>
+NdefMessage msg = new NdefMessage(
+ new NdefRecord[] {
+ ...,
+ NdefRecord.createApplicationRecord("com.example.android.beam")}
+</pre>
+
+
+<h2 id="p2p">Beaming NDEF Messages to Other Devices</h2>
+
+<p>Android Beam allows simple peer-to-peer data exchange between two Android-powered devices. The
+application that wants to beam data to another device must be in the foreground and the device
+receiving the data must not be locked. When the beaming device comes in close enough contact with a
+receiving device, the beaming device displays the "Touch to Beam" UI. The user can then choose
+whether or not to beam the message to the receiving device.</p>
+
+<p class="note"><strong>Note:</strong> Foreground NDEF pushing was available at API level 10,
+which provides similar functionality to Android Beam. These APIs have since been deprecated, but
+are available to support older devices. See {@link android.nfc.NfcAdapter#enableForegroundNdefPush
+enableForegroundNdefPush()} for more information.</p>
+
+<p>You can enable Android Beam for your application by calling one of the two methods:</p>
+ <ul>
+ <li>{@link android.nfc.NfcAdapter#setNdefPushMessage setNdefPushMessage()}: Accepts an
+{@link android.nfc.NdefMessage} to set as the message to beam. Automatically beams the message
+when two devices are in close enough proximity.</li>
+ <li>{@link android.nfc.NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback()}:
+Accepts a callback that contains a
+{@link android.nfc.NfcAdapter.CreateNdefMessageCallback#createNdefMessage createNdefMessage()}
+which is called when a device is in range to beam data to. The callback lets you create
+the NDEF message only when necessary.</li>
+ </ul>
+
+<p>An activity can only push one NDEF message at a time, so {@link
+android.nfc.NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback()} takes precedence
+over {@link android.nfc.NfcAdapter#setNdefPushMessage setNdefPushMessage()} if both are set. To use
+Android Beam, the following general guidelines must be met:
+</p>
+
+ <ul>
+ <li>The activity that is beaming the data must be in the foreground. Both devices must have
+their screens unlocked.</li>
+
+ <li>You must encapsulate the data that you are beaming in an {@link android.nfc.NdefMessage}
+ object.</li>
+
+ <li>The NFC device that is receiving the beamed data must support the
+ <code>com.android.npp</code> NDEF push protocol or NFC Forum's SNEP (Simple NDEF Exchange
+Protocol). The <code>com.android.npp</code> protocol is required for devices on API level 9 (Android
+2.3) to API level 13 (Android 3.2). <code>com.android.npp</code> and SNEP are both required on
+API level 14 (Android 4.0) and later.</li>
+</li>
+ </ul>
+
+ <p class="note"><strong>Note:</strong> If your activity enables Android Beam and is
+in the foreground, the standard intent dispatch system is disabled. However, if your activity also
+enables <a href="{@docRoot}guide/topics/nfc/advanced-nfc.html#foreground-dispatch">foreground
+dispatching</a>, then it can still scan tags that match the intent filters set in the foreground
+dispatching.</p>
+
+ <p>To enable Android Beam:</p>
+
+ <ol>
+ <li>Create an {@link android.nfc.NdefMessage} that contains the {@link android.nfc.NdefRecord}s
+that you want to push onto the other device.</li>
+
+ <li>Call {@link
+android.nfc.NfcAdapter#setNdefPushMessage setNdefPushMessage()} with a {@link
+android.nfc.NdefMessage} or call {@link
+android.nfc.NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback} passing in a {@link
+android.nfc.NfcAdapter.CreateNdefMessageCallback} object in the <code>onCreate()</code> method of
+your activity. These methods require at least one activity that you want to enable with Android
+Beam, along with an optional list of other activities to activate.
+
+<p>In general, you normally use {@link
+android.nfc.NfcAdapter#setNdefPushMessage setNdefPushMessage()} if your Activity only needs to
+push the same NDEF message at all times, when two devices are in range to communicate. You use
+{@link android.nfc.NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback} when your
+application cares about the current context of the application and wants to push an NDEF message
+depending on what the user is doing in your application.</p>
+ </li>
+ </ol>
+
+<p>The following sample shows how a simple activity calls {@link
+android.nfc.NfcAdapter.CreateNdefMessageCallback} in the <code>onCreate()</code> method of an
+activity (see <a href="{@docRoot}resources/samples/AndroidBeam/index.html"></a> for the
+complete sample). This example also has methods to help you create a MIME record:</p>
+
+<pre id="code-example">
+package com.example.android.beam;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.nfc.NdefMessage;
+import android.nfc.NdefRecord;
+import android.nfc.NfcAdapter;
+import android.nfc.NfcAdapter.CreateNdefMessageCallback;
+import android.nfc.NfcEvent;
+import android.os.Bundle;
+import android.os.Parcelable;
+import android.widget.TextView;
+import android.widget.Toast;
+import java.nio.charset.Charset;
+
+
+public class Beam extends Activity implements CreateNdefMessageCallback {
+ NfcAdapter mNfcAdapter;
+ TextView textView;
+
+ @Override
+ public void onCreate(Bundle savedInstanceState) {
+ super.onCreate(savedInstanceState);
+ setContentView(R.layout.main);
+ TextView textView = (TextView) findViewById(R.id.textView);
+ // Check for available NFC Adapter
+ mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
+ if (mNfcAdapter == null) {
+ Toast.makeText(this, "NFC is not available", Toast.LENGTH_LONG).show();
+ finish();
+ return;
+ }
+ // Register callback
+ mNfcAdapter.setNdefPushMessageCallback(this, this);
+ }
+
+ @Override
+ public NdefMessage createNdefMessage(NfcEvent event) {
+ String text = ("Beam me up, Android!\n\n" +
+ "Beam Time: " + System.currentTimeMillis());
+ NdefMessage msg = new NdefMessage(
+ new NdefRecord[] { createMimeRecord(
+ "application/com.example.android.beam", text.getBytes())
+ /**
+ * The Android Application Record (AAR) is commented out. When a device
+ * receives a push with an AAR in it, the application specified in the AAR
+ * is guaranteed to run. The AAR overrides the tag dispatch system.
+ * You can add it back in to guarantee that this
+ * activity starts when receiving a beamed message. For now, this code
+ * uses the tag dispatch system.
+ */
+ //,NdefRecord.createApplicationRecord("com.example.android.beam")
+ });
+ return msg;
+ }
+
+ @Override
+ public void onResume() {
+ super.onResume();
+ // Check to see that the Activity started due to an Android Beam
+ if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
+ processIntent(getIntent());
+ }
+ }
+
+ @Override
+ public void onNewIntent(Intent intent) {
+ // onResume gets called after this to handle the intent
+ setIntent(intent);
+ }
+
+ /**
+ * Parses the NDEF Message from the intent and prints to the TextView
+ */
+ void processIntent(Intent intent) {
+ textView = (TextView) findViewById(R.id.textView);
+ Parcelable[] rawMsgs = intent.getParcelableArrayExtra(
+ NfcAdapter.EXTRA_NDEF_MESSAGES);
+ // only one message sent during the beam
+ NdefMessage msg = (NdefMessage) rawMsgs[0];
+ // record 0 contains the MIME type, record 1 is the AAR, if present
+ textView.setText(new String(msg.getRecords()[0].getPayload()));
+ }
+
+ /**
+ * Creates a custom MIME type encapsulated in an NDEF record
+ */
+ public NdefRecord createMimeRecord(String mimeType, byte[] payload) {
+ byte[] mimeBytes = mimeType.getBytes(Charset.forName("US-ASCII"));
+ NdefRecord mimeRecord = new NdefRecord(
+ NdefRecord.TNF_MIME_MEDIA, mimeBytes, new byte[0], payload);
+ return mimeRecord;
+ }
+}
+</pre>
+
+<p>Note that this code comments out an AAR, which you can remove. If you enable the AAR, the
+application specified in the AAR always receives the Android Beam message. If the application is not
+present, the Android Market is started to download the application. Therefore, the following intent
+filter is not technically necessary for Android 4.0 devices or later if the AAR is used:
+</p>
+
+<pre>
+<intent-filter>
+ <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
+ <category android:name="android.intent.category.DEFAULT"/>
+ <data android:mimeType="application/com.example.android.beam"/>
+</intent-filter>
+</pre>
+<p>With this intent filter, the <code>com.example.android.beam</code> application now can be started
+when it scans an NFC tag or receives an Android Beam with an AAR of
+type <code>com.example.android.beam</code>, or when an NDEF formatted message contains a MIME record
+of type <code>application/com.example.android.beam</code>.</p>
+
+<p>Even though AARs guarantee an application is started or downloaded, intent filters are
+recommended, because they let you start an Activity of your choice in your
+application instead of always starting the main Activity within the package specified by an AAR.
+AARs do not have Activity level granularity. Also, because some Android-powered devices do not
+support AARs, you should also embed identifying information in the first NDEF record of your NDEF
+messages and filter for that as well, just in case. See <a href="#creating-records">Creating Common
+Types of NDEF records</a> for more information on how to create records.
+</p>
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