android nfc中Ndef格式的读写
检测到标签后在Activity中的处理流程
1. 在onCreate()中获取NfcAdapter对象；
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
2.在onNewIntent()中获取Tag对象或者NdefMessage信息；
获取Tag对象：
Tag tag = intent.getParcelableExra(NfcAdapter.EXTRA_TAG);
获取NdefMessage信息：
Parcelable[] rawMsgs = getIntent().getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES)
3.也可以通过Tag创建Ndef对象等，以实现标签的属性和I/O操作。
Ndef ndef = Ndef.get(tag)；
NDEF格式标签的读取流程
1. 在onCreate()中获取NfcAdapter对象；
2.在onNewIntent()中判断是否为NDEF格式标签（ACTION_NDEF_DISCOVERED），若是则获取NdefMessage
信息；（需要强制转换成NdefMessage对象）
Parcelable[] rawMsgs = getIntent().getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES)
3.对NdefMessage对象进行解析，获取相关的文本信息或Uri等。
NDEF格式标签的写入流程
1. 在onCreate()中获取NfcAdapter对象；
2.在onNewIntent()中获取Tag对象；
Tag tag = intent.getParcelableExra(NfcAdapter.EXTRA_TAG);
3.通过Tag创建Ndef对象；
Ndef ndef = Ndef.get(tag)；
4.将文本等数据封装成NdefMessage；
5.判断是否为NDEF格式标签，
若是NDEF格式：
(1)允许进行标签操作:ndef.connect();
(2) 调用ndef.writeNdefMessage(NdefMessage)方法写入。
若非NDEF格式：
(1)NdefFromatable format = NdefFromatable.get();
(2)允许进行标签操作:format.connect();
(3)调用format.format(NdefMessage)方法写入。
NdefMessage信息结构
Supported TNFs and their mappings：
TNF_ABSOLUTE_URI |
URI based on the type field. |
TNF_EMPTY |
Falls back toACTION_TECH_DISCOVERED. |
TNF_EXTERNAL_TYPE |
URI based on the URN in the type field. The URN is encoded into the NDEF type field in a shortened form:<domain_name>:<service_name>. Android maps this to a URI in the form:vnd.android.nfc://ext/<domain_name>:<service_name>. |
TNF_MIME_MEDIA |
MIME type based on the type field. |
TNF_UNCHANGED |
Invalid in the first record, so falls back toACTION_TECH_DISCOVERED. |
TNF_UNKNOWN |
Falls back toACTION_TECH_DISCOVERED. |
TNF_WELL_KNOWN |
MIME type or URI depending on the Record Type Definition (RTD), which you set in the type field. SeeTable 2.for more information on available RTDs and their mappings. |
RTD_ALTERNATIVE_CARRIER |
Falls back toACTION_TECH_DISCOVERED. |
RTD_HANDOVER_CARRIER |
Falls back toACTION_TECH_DISCOVERED. |
RTD_HANDOVER_REQUEST |
Falls back toACTION_TECH_DISCOVERED. |
RTD_HANDOVER_SELECT |
Falls back toACTION_TECH_DISCOVERED. |
RTD_SMART_POSTER |
URI based on parsing the payload. |
RTD_TEXT |
MIME type oftext/plain. |
RTD_URI |
URI based on payload. |
说明：读取TNF的类型后（可以是上面第一张表中的类型），如果是TNF_WELL_KNOWN时，就可以获取RTD（对应格式良好的
{TNF_WELL_KNOWN}的标签的类型，可以是第二张表中的类型）
NdefRecord中的常用方法
1.可通过NdefRecord.getTnf()方法来获得TNF字段；
对应上图中Header中的Length
2.通过NdefRecord.getType()方法来获得RTD字段，当TNF为TNF_WELL_KNOWN时的RTD。
对应上图中Header中的Type
3.通过NdefRecord.getPayload()方法来获得实际读写的数据。
Header中的Identifier对应每个Record唯一的Id对应上图中的Payload
NDEF文本格式
NdefMessage中的paylaod就是实际的数据，其中NDEF文本格式为：
NDEF Uri格式
1、NdefMessage中的paylaod就是实际的数据，其中NDEF文本格式为：
2、前缀需要查表解析
Android应用程序记录Android Application Records(AAR)
1、在Android4.0中引入应用程序记录（AAR），当扫描到写入AAR的NFC标签时，启动相应的应用程序。
2、AAR有嵌入到NdefRecord内部的应用程序包名。Android会针对AAR来搜索整个NdefMessage，如果找到一个AAR，就会基于AAR内部的包名来启动应用程序。
3、NFC标签调度系统对包含AAR标签的调度：
1.若跟Intent匹配的Activity也跟AAR匹配，则启动该Activity；
2.若跟Intent匹配，而跟AAR不匹配，则启动AAR指定的应用程序；
3.如果没有跟AAR对应的应用程序，则启动各种市场来下载对应基于AAR的应用程序。
Android应用程序记录创建方法
1、调用NdefRecord类的creatApplicationRecord()方法来创建应用程序记录。
2、将所创建的AAR嵌入到NdefMessage中。
NdefMessage msg = new NdefMessage(new Ndefrecord[]{…,NdefRecord. creatApplicationRecord(“com.example.android.beam”)})
3、除非AAR是你NdefMessage中的唯一记录，否则不要将AAR嵌入到NdefMessage的第一条记录。
NDEF for Text 读写，例子程序：
ReadWriteTextMainActivity：
package mobile.android.read.write.text;
import java.nio.charset.Charset;
import java.util.Locale;
import android.app.Activity;
import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class ReadWriteTextMainActivity extends Activity {
private TextView mInputText;
private String mText;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_read_write_text_main);
mInputText = (TextView) findViewById(R.id.textview_input_text);
}
//单击“输入要写入文本”按钮执行的方法
public void onClick_InputText(View view) {
Intent intent = new Intent(this, InputTextActivity.class);
//显示输入文本的界面
startActivityForResult(intent, 1);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1 && resultCode == 1) {
//获取要写入标签的文本
mText = data.getStringExtra("text");
//在主界面显示要写入标签的文本
mInputText.setText(mText);
}
}
//当窗口的创建模式是singleTop或singleTask时调用，用于取代onCreate方法
//当NFC标签靠近手机，建立连接后调用
@Override
public void onNewIntent(Intent intent) {
//如果未设置要写入的文本，则读取标签上的文本数据
if (mText == null) {
Intent myIntent = new Intent(this, ShowNFCTagContentActivity.class);
//将intent传入另一个窗口，显示界面窗口
myIntent.putExtras(intent);
//需要指定这个Action，传递Intent对象时，Action不会传递
myIntent.setAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
startActivity(myIntent);
}
//将指定的文本写入NFC标签
else {
//获取Tag对象
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
//创建NdefMessage对象和NdefRecord对象
NdefMessage ndefMessage = new NdefMessage(
new NdefRecord[] {createTextRecord(mText)});
//开始向标签写入文本
if (writeTag(ndefMessage, tag)) {
//如果成功写入文本，将mtext设为null
mText = null;
//将主窗口显示的要写入的文本清空，文本只能写入一次
//如要继续写入，需要再次指定新的文本，否则只会读取标签中的文本
mInputText.setText("");
}
}
}
//创建一个封装要写入的文本的NdefRecord对象
public NdefRecord createTextRecord(String text) {
//生成语言编码的字节数组，中文编码
byte[] langBytes = Locale.CHINA.getLanguage().getBytes(
Charset.forName("US-ASCII"));
//将要写入的文本以UTF_8格式进行编码
Charset utfEncoding = Charset.forName("UTF-8");
//由于已经确定文本的格式编码为UTF_8，所以直接将payload的第1个字节的第7位设为0
byte[] textBytes = text.getBytes(utfEncoding);
int utfBit = 0;
//定义和初始化状态字节
char status = (char) (utfBit + langBytes.length);
//创建存储payload的字节数组
byte[] data = new byte[1 + langBytes.length + textBytes.length];
//设置状态字节
data[0] = (byte) status;
//设置语言编码
System.arraycopy(langBytes, 0, data, 1, langBytes.length);
//设置实际要写入的文本
System.arraycopy(textBytes, 0, data, 1 + langBytes.length,
textBytes.length);
//根据前面设置的payload创建NdefRecord对象
NdefRecord record = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
NdefRecord.RTD_TEXT, new byte[0], data);
return record;
}
//将NdefMessage对象写入标签，成功写入返回ture，否则返回false
boolean writeTag(NdefMessage message, Tag tag) {
int size = message.toByteArray().length;
try {
//获取Ndef对象
Ndef ndef = Ndef.get(tag);
if (ndef != null) {
//允许对标签进行IO操作
ndef.connect();
if (!ndef.isWritable()) {
Toast.makeText(this, "NFC Tag是只读的！", Toast.LENGTH_LONG)
.show();
return false;
}
if (ndef.getMaxSize() < size) {
Toast.makeText(this, "NFC Tag的空间不足！", Toast.LENGTH_LONG)
.show();
return false;
}
//向标签写入数据
ndef.writeNdefMessage(message);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG).show();
return true;
} else {
//获取可以格式化和向标签写入数据NdefFormatable对象
NdefFormatable format = NdefFormatable.get(tag);
//向非NDEF格式或未格式化的标签写入NDEF格式数据
if (format != null) {
try {
//允许对标签进行IO操作
format.connect();
format.format(message);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG)
.show();
return true;
} catch (Exception e) {
Toast.makeText(this, "写入NDEF格式数据失败！", Toast.LENGTH_LONG)
.show();
return false;
}
} else {
Toast.makeText(this, "NFC标签不支持NDEF格式！", Toast.LENGTH_LONG)
.show();
return false;
}
}
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
return false;
}
}
}
InputTextActivity：
package mobile.android.read.write.text;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
public class InputTextActivity extends Activity {
private EditText mTextTag;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_input_text);
mTextTag = (EditText) findViewById(R.id.edittext_text_tag);
}
public void onClick_OK(View view) {
Intent intent = new Intent();
intent.putExtra("text", mTextTag.getText().toString());
setResult(1, intent);
finish();
}
}
ShowNFCTagContentActivity：
package mobile.android.read.write.text;
import mobile.android.read.write.text.library.TextRecord;
import android.app.Activity;
import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.os.Bundle;
import android.os.Parcelable;
import android.widget.TextView;
import android.widget.Toast;
public class ShowNFCTagContentActivity extends Activity {
private TextView mTagContent;
private Tag mDetectedTag;
private String mTagText;
private void readAndShowData(Intent intent) {
mDetectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
Ndef ndef = Ndef.get(mDetectedTag);
mTagText = ndef.getType() + "\n最大数据容量：" + ndef.getMaxSize()
+ " bytes\n\n";
readNFCTag();
mTagContent.setText(mTagText);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_nfctag_content);
mTagContent = (TextView) findViewById(R.id.textview_tag_content);
//获取Tag对象
mDetectedTag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
//创建Ndef对象
Ndef ndef = Ndef.get(mDetectedTag);
//获取标签的类型和最大容量
mTagText = ndef.getType() + "\n最大数据容量：" + ndef.getMaxSize()
+ " bytes\n\n";
//读取NFC标签的数据并解析
readNFCTag();
//将标签的相关信息显示在界面上
mTagContent.setText(mTagText);
}
private void readNFCTag() {
//判断是否为ACTION_NDEF_DISCOVERED
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
//从标签读取数据（Parcelable对象）
Parcelable[] rawMsgs = getIntent().getParcelableArrayExtra(
NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefMessage msgs[] = null;
int contentSize = 0;
if (rawMsgs != null) {
msgs = new NdefMessage[rawMsgs.length];
//标签可能存储了多个NdefMessage对象，一般情况下只有一个NdefMessage对象
for (int i = 0; i < rawMsgs.length; i++) {
//转换成NdefMessage对象
msgs[i] = (NdefMessage) rawMsgs[i];
//计算数据的总长度
contentSize += msgs[i].toByteArray().length;
}
}
try {
if (msgs != null) {
//程序中只考虑了1个NdefRecord对象，若是通用软件应该考虑所有的NdefRecord对象
NdefRecord record = msgs[0].getRecords()[0];
//分析第1个NdefRecorder，并创建TextRecord对象
TextRecord textRecord = TextRecord.parse(msgs[0]
.getRecords()[0]);
//获取实际的数据占用的大小，并显示在窗口上
mTagText += textRecord.getText() + "\n\n纯文本\n"
+ contentSize + " bytes";
}
} catch (Exception e) {
mTagContent.setText(e.getMessage());
}
}
}
}
TextRecord：
package mobile.android.read.write.text.library;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import android.nfc.NdefRecord;
public class TextRecord {
//存储解析出来的文本
private final String mText;
//不允许直接创建TextRecord对象，所以将构造方法声明为private
private TextRecord(String text) {
mText = text;
}
//通过该方法可以获取解析出来的文本
public String getText() {
return mText;
}
// 将纯文本内容从NdefRecord对象（payload）中解析出来
public static TextRecord parse(NdefRecord record) {
//验证TNF是否为NdefRecord.TNF_WELL_KNOWN
if (record.getTnf() != NdefRecord.TNF_WELL_KNOWN)
return null;
//验证可变长度类型是否为RTD_TEXT
if (!Arrays.equals(record.getType(), NdefRecord.RTD_TEXT))
return null;
try {
//获取payload
byte[] payload = record.getPayload();
//下面代码分析payload：状态字节+ISO语言编码（ASCLL）+文本数据（UTF_8/UTF_16）
//其中payload[0]放置状态字节：如果bit7为0，文本数据以UTF_8格式编码，如果为1则以UTF_16编码
//bit6是保留位，默认为0
/*
* payload[0] contains the "Status Byte Encodings" field, per the
* NFC Forum "Text Record Type Definition" section 3.2.1.
*
* bit7 is the Text Encoding Field.
*
* if (Bit_7 == 0): The text is encoded in UTF-8 if (Bit_7 == 1):
* The text is encoded in UTF16
*
* Bit_6 is reserved for future use and must be set to zero.
*
* Bits 5 to 0 are the length of the IANA language code.
*/
String textEncoding = ((payload[0] & 0x80) == 0) ? "UTF-8"
: "UTF-16";
//处理bit5-0。bit5-0表示语言编码长度（字节数）
int languageCodeLength = payload[0] & 0x3f;
//获取语言编码（从payload的第2个字节读取languageCodeLength个字节作为语言编码）
String languageCode = new String(payload, 1, languageCodeLength,
"US-ASCII");
//解析出实际的文本数据
String text = new String(payload, languageCodeLength + 1,
payload.length - languageCodeLength - 1, textEncoding);
//创建一个TextRecord对象，并返回该对象
return new TextRecord(text);
} catch (UnsupportedEncodingException e) {
// should never happen unless we get a malformed tag.
throw new IllegalArgumentException(e);
}
}
}
AndroidManifest.xml：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mobile.android.read.write.text"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.NFC" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".ReadWriteTextMainActivity"
android:label="读写NFC标签的纯文本数据"
android:launchMode="singleTask" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="text/plain" />
</intent-filter>
</activity>
<activity
android:name=".ShowNFCTagContentActivity"
android:label="显示NFC标签内容"
android:launchMode="singleTask" />
<activity
android:name=".InputTextActivity"
android:label="向NFC标签写入文本" />
</application>
</manifest>
NDEF for URL 读写，例子程序：
ReadWriteUriMainActivity：
package mobile.android.read.write.uri;
import mobile.android.read.write.uri.library.UriRecord;
import android.app.Activity;
import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class ReadWriteUriMainActivity extends Activity {
private TextView mSelectUri;
private String mUri;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_read_write_uri_main);
mSelectUri = (TextView) findViewById(R.id.textview_uri);
}
public void onClick_SelectUri(View view) {
Intent intent = new Intent(this, UriListActivity.class);
startActivityForResult(intent, 1);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1 && resultCode == 1) {
mUri = data.getStringExtra("uri");
mSelectUri.setText(mUri);
}
}
@Override
public void onNewIntent(Intent intent) {
if (mUri == null) {
Intent myIntent = new Intent(this, ShowNFCTagContentActivity.class);
myIntent.putExtras(intent);
myIntent.setAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
startActivity(myIntent);
} else {
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
NdefMessage ndefMessage = new NdefMessage(
new NdefRecord[] {createUriRecord(mUri)});
if (writeTag(ndefMessage, tag)) {
mUri = null;
mSelectUri.setText("");
}
}
}
public NdefRecord createUriRecord(String uriStr) {
byte prefix = 0;
//从uri前缀集合中找到匹配的前缀，并获得相应的标识代码
for (Byte b : UriRecord.URI_PREFIX_MAP.keySet()) {
//将Uri前缀转换成小写
String prefixStr = UriRecord.URI_PREFIX_MAP.get(b).toLowerCase();
//前缀不为空串
if ("".equals(prefixStr))
continue;
//比较Uri前缀
if (uriStr.toLowerCase().startsWith(prefixStr)) {
//用字节表示的Uri前缀
prefix = b;
//截取完整Uri中除了Uri前缀外的其他部分
uriStr = uriStr.substring(prefixStr.length());
break;
}
}
//为存储在标签中的Uri创建一个Byte数组
byte[] data = new byte[1 + uriStr.length()];
//指定第1字节为Uri前缀的标识代码
data[0] = prefix;
//将剩余的部分复制到data字节数组中
System.arraycopy(uriStr.getBytes(), 0, data, 1, uriStr.length());
//创建封装uri的NdefRecord对象
NdefRecord record = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
NdefRecord.RTD_URI, new byte[0], data);
//返回NdefRecord对象
return record;
}
boolean writeTag(NdefMessage message, Tag tag) {
int size = message.toByteArray().length;
try {
Ndef ndef = Ndef.get(tag);
if (ndef != null) {
ndef.connect();
if (!ndef.isWritable()) {
Toast.makeText(this, "NFC Tag是只读的！", Toast.LENGTH_LONG)
.show();
return false;
}
if (ndef.getMaxSize() < size) {
Toast.makeText(this, "NFC Tag的空间不足！", Toast.LENGTH_LONG)
.show();
return false;
}
ndef.writeNdefMessage(message);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG).show();
return true;
} else {
NdefFormatable format = NdefFormatable.get(tag);
if (format != null) {
try {
format.connect();
format.format(message);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG)
.show();
return true;
} catch (Exception e) {
Toast.makeText(this, "写入NDEF格式数据失败！", Toast.LENGTH_LONG)
.show();
return false;
}
} else {
Toast.makeText(this, "NFC标签不支持NDEF格式！", Toast.LENGTH_LONG)
.show();
return false;
}
}
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
return false;
}
}
}
UriListActivity:package mobile.android.read.write.uri;
import android.app.ListActivity;
import android.content.Intent;
import android.graphics.Camera;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.SimpleAdapter;
public class UriListActivity extends ListActivity implements
OnItemClickListener {
private String uris[] = new String[] {"http://www.google.com",
"http://www.apple.com", "http://developer.apple.com",
"http://www.126.com", "ftp://192.168.17.160",
"https://192.168.17.120", "smb://192.168.17.100"};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, uris);
setListAdapter(arrayAdapter);
getListView().setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
Intent intent = new Intent();
intent.putExtra("uri", uris[position]);
setResult(1, intent);
finish();
}
}
ShowNFCTagContentActivity:
package mobile.android.read.write.uri;
import mobile.android.read.write.uri.library.UriRecord;
import android.app.Activity;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.os.Bundle;
import android.os.Parcelable;
import android.widget.TextView;
public class ShowNFCTagContentActivity extends Activity {
private TextView mTagContent;
private Tag mDetectedTag;
private String mTagText;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_nfctag_content);
mTagContent = (TextView) findViewById(R.id.textview_tag_content);
mDetectedTag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
Ndef ndef = Ndef.get(mDetectedTag);
mTagText = ndef.getType() + "\n最大数据容量：" + ndef.getMaxSize()
+ " bytes\n\n";
readNFCTag();
mTagContent.setText(mTagText);
}
private void readNFCTag() {
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
Parcelable[] rawMsgs = getIntent().getParcelableArrayExtra(
NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefMessage ndefMessage = null;
int contentSize = 0;
if (rawMsgs != null) {
if (rawMsgs.length > 0) {
ndefMessage = (NdefMessage) rawMsgs[0];
contentSize = ndefMessage.toByteArray().length;
} else {
return;
}
}
try {
NdefRecord record = ndefMessage.getRecords()[0];
UriRecord uriRecord = UriRecord
.parse(ndefMessage.getRecords()[0]);
mTagText += uriRecord.getUri().toString() + "\n\nUri\n"
+ contentSize + " bytes";
} catch (Exception e) {
mTagContent.setText(e.getMessage());
}
}
}
}
UriRecord.java
package mobile.android.read.write.uri.library;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import android.net.Uri;
import android.nfc.NdefRecord;
public class UriRecord {
//映射Uri前缀和对应的值
public static final Map<Byte, String> URI_PREFIX_MAP = new HashMap<Byte, String>();
static {
//设置NDEF Uri规范支持的Uri前缀，在解析payload时，需要根据payload的第1个字节定位相应的uri前缀
URI_PREFIX_MAP.put((byte) 0x00, "");
URI_PREFIX_MAP.put((byte) 0x01, "http://www.");
URI_PREFIX_MAP.put((byte) 0x02, "https://www.");
URI_PREFIX_MAP.put((byte) 0x03, "http://");
URI_PREFIX_MAP.put((byte) 0x04, "https://");
URI_PREFIX_MAP.put((byte) 0x05, "tel:");
URI_PREFIX_MAP.put((byte) 0x06, "mailto:");
URI_PREFIX_MAP.put((byte) 0x07, "ftp://anonymous:anonymous@");
URI_PREFIX_MAP.put((byte) 0x08, "ftp://ftp.");
URI_PREFIX_MAP.put((byte) 0x09, "ftps://");
URI_PREFIX_MAP.put((byte) 0x0A, "sftp://");
URI_PREFIX_MAP.put((byte) 0x0B, "smb://");
URI_PREFIX_MAP.put((byte) 0x0C, "nfs://");
URI_PREFIX_MAP.put((byte) 0x0D, "ftp://");
URI_PREFIX_MAP.put((byte) 0x0E, "dav://");
URI_PREFIX_MAP.put((byte) 0x0F, "news:");
URI_PREFIX_MAP.put((byte) 0x10, "telnet://");
URI_PREFIX_MAP.put((byte) 0x11, "imap:");
URI_PREFIX_MAP.put((byte) 0x12, "rtsp://");
URI_PREFIX_MAP.put((byte) 0x13, "urn:");
URI_PREFIX_MAP.put((byte) 0x14, "pop:");
URI_PREFIX_MAP.put((byte) 0x15, "sip:");
URI_PREFIX_MAP.put((byte) 0x16, "sips:");
URI_PREFIX_MAP.put((byte) 0x17, "tftp:");
URI_PREFIX_MAP.put((byte) 0x18, "btspp://");
URI_PREFIX_MAP.put((byte) 0x19, "btl2cap://");
URI_PREFIX_MAP.put((byte) 0x1A, "btgoep://");
URI_PREFIX_MAP.put((byte) 0x1B, "tcpobex://");
URI_PREFIX_MAP.put((byte) 0x1C, "irdaobex://");
URI_PREFIX_MAP.put((byte) 0x1D, "file://");
URI_PREFIX_MAP.put((byte) 0x1E, "urn:epc:id:");
URI_PREFIX_MAP.put((byte) 0x1F, "urn:epc:tag:");
URI_PREFIX_MAP.put((byte) 0x20, "urn:epc:pat:");
URI_PREFIX_MAP.put((byte) 0x21, "urn:epc:raw:");
URI_PREFIX_MAP.put((byte) 0x22, "urn:epc:");
URI_PREFIX_MAP.put((byte) 0x23, "urn:nfc:");
}
private final Uri mUri;
private UriRecord(Uri uri) {
this.mUri = uri;
}
//获取已经解析的Uri
public Uri getUri() {
return mUri;
}
public static UriRecord parse(NdefRecord record) {
//获取TNF
short tnf = record.getTnf();
//TNF是TNF_WELL_KNOWN，使用了前缀的Uri
if (tnf == NdefRecord.TNF_WELL_KNOWN) {
return parseWellKnown(record);
}
//TNF是TNF_ABSOLUTE_URI，即绝对Uri，不使用前缀
else if (tnf == NdefRecord.TNF_ABSOLUTE_URI) {
return parseAbsolute(record);
}
throw new IllegalArgumentException("Unknown TNF " + tnf);
}
/** Parse and absolute URI record */
private static UriRecord parseAbsolute(NdefRecord record) {
//直接将payload转成uri
byte[] payload = record.getPayload();
Uri uri = Uri.parse(new String(payload, Charset.forName("UTF-8")));
return new UriRecord(uri);
}
/** Parse an well known URI record */
private static UriRecord parseWellKnown(NdefRecord record) {
//判断RTD是否为RTD_URI
if (!Arrays.equals(record.getType(), NdefRecord.RTD_URI))
return null;
byte[] payload = record.getPayload();
/*
* payload[0] contains the URI Identifier Code, per the NFC Forum
* "URI Record Type Definition" section 3.2.2.
*
* payload[1]...payload[payload.length - 1] contains the rest of the
* URI.
*/
//payload[0]中包括URI标识代码，也就是URI_PREFIX_MAP中的key
//根据Uri标识代码获取Uri前缀
String prefix = URI_PREFIX_MAP.get(payload[0]);
//获取Uri前缀占用的字节数
byte[] prefixBytes = prefix.getBytes(Charset.forName("UTF-8"));
//为容纳完整的Uri创建一个byte数组
byte[] fullUri = new byte[prefixBytes.length + payload.length - 1];
//将Uri前缀和其余部分组合，形成一个完整的Uri
System.arraycopy(prefixBytes, 0, fullUri, 0, prefixBytes.length);
System.arraycopy(payload, 1, fullUri, prefixBytes.length,
payload.length - 1);
//根据解析出来的Uri创建Uri对象
Uri uri = Uri.parse(new String(fullUri, Charset.forName("UTF-8")));
//创建UriRecord对象并返回
return new UriRecord(uri);
}
}
清单文件：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mobile.android.read.write.uri"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.NFC" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".ReadWriteUriMainActivity"
android:label="读写NFC标签的Uri"
android:launchMode="singleTask" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="http" />
<data android:scheme="https" />
<data android:scheme="ftp" />
</intent-filter>
</activity>
<activity
android:name=".ShowNFCTagContentActivity"
android:label="显示NFC标签内容" />
<activity
android:name=".UriListActivity"
android:label="选择Uri" />
</application>
</manifest>
AAR例子程序：
AutoRunApplicationActivity：
package mobile.android.auto.run.application;
import java.net.URI;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.net.Uri;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class AutoRunApplicationActivity extends Activity {
private Button mSelectAutoRunApplication;
private String mPackageName;
private NfcAdapter mNfcAdapter;
private PendingIntent mPendingIntent;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_auto_run_application);
mSelectAutoRunApplication = (Button) findViewById(R.id.button_select_auto_run_application);
//获得默认的NfcAdapter对象
mNfcAdapter = mNfcAdapter.getDefaultAdapter(this);
//创建与当前Activity关联的PendingIntent对象
mPendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
getClass()), 0);
}
//当窗口获得焦点时会提升当前窗口处理NFC标签的优先级
@Override
public void onResume() {
super.onResume();
//提升当前处理NFC标签的优先级
if (mNfcAdapter != null)
mNfcAdapter.enableForegroundDispatch(this, mPendingIntent, null,
null);
}
//当窗口的launchMode被设为singleTop时调用方法（不再调用onCreat方法）
@Override
public void onNewIntent(Intent intent) {
//必须先选择一个Package
if (mPackageName == null)
return;
//获取表示当前标签的对象
Tag detectedTag = intent.getParcelableExtra(mNfcAdapter.EXTRA_TAG);
//向标签写入Package
writeNFCTag(detectedTag);
}
//当窗口失去焦点后，应恢复Android系统处理NFC标签的默认状态
@Override
public void onPause() {
super.onPause();
//恢复处理NFC标签的窗口的默认优先级（禁止当前窗口的优先处理NFC标签）
if (mNfcAdapter != null)
mNfcAdapter.disableForegroundDispatch(this);
}
//"选择已安装的应用程序"按钮的单击事件方法
public void onClick_SelectAutoRunApplication(View view) {
Intent intent = new Intent(this, InstalledApplicationListActivity.class);
//显示“已安装应用程序”窗口
startActivityForResult(intent, 0);
}
//向标签写入数据
public void writeNFCTag(Tag tag) {
//必须要指定一个Tag对象
if (tag == null) {
Toast.makeText(this, "NFC Tag未建立连接", Toast.LENGTH_LONG).show();
return;
}
//创建NdefMessage对象
//NdefRecord.creatApplicationRecord方法创建一个封装Package的NdefRecord对象
NdefMessage ndefMessage = new NdefMessage(
new NdefRecord[] {NdefRecord
.createApplicationRecord(mPackageName)});
//获取NdefMessage对象的尺寸
int size = ndefMessage.toByteArray().length;
try {
//获取Ndef对象
Ndef ndef = Ndef.get(tag);
//处理NDEF格式的数据
if (ndef != null) {
//允许对标签进行IO操作，连接
ndef.connect();
//NFC标签不是可写的（只读的）
if (!ndef.isWritable()) {
Toast.makeText(this, "NFC Tag是只读的！", Toast.LENGTH_LONG)
.show();
return;
}
//NFC标签的空间不足
if (ndef.getMaxSize() < size) {
Toast.makeText(this, "NFC Tag的空间不足！", Toast.LENGTH_LONG)
.show();
return;
}
//向NFC标签写入数据
ndef.writeNdefMessage(ndefMessage);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG).show();
} else {
//创建NdefFormatable对象
NdefFormatable format = NdefFormatable.get(tag);
if (format != null) {
try {
//允许标签IO操作，进行连接
format.connect();
//重新格式化NFC标签，并写入数据
format.format(ndefMessage);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG)
.show();
} catch (Exception e) {
Toast.makeText(this, "写入NDEF格式数据失败！", Toast.LENGTH_LONG)
.show();
}
} else {
Toast.makeText(this, "NFC标签不支持NDEF格式！", Toast.LENGTH_LONG)
.show();
}
}
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == 1) {
//更新“选择已安装的应用程序”按钮的显示文本（Package name和label）
mSelectAutoRunApplication.setText(data.getExtras().getString(
"package_name"));
//下面的代码用于提取Package Name
String temp = mSelectAutoRunApplication.getText().toString();
mPackageName = temp.substring(temp.indexOf("\n") + 1);
}
}
}
InstalledApplicationListActivity：
package mobile.android.auto.run.application;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
public class InstalledApplicationListActivity extends ListActivity implements
OnItemClickListener {
//用于保存已安装应用程序的Package和Label
private List<String> mPackages = new ArrayList<String>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//获得PackageManager对象
PackageManager packageManager = getPackageManager();
//获取系统中已安装的所有应用程序的信息，每一个PackageInfo对象表示一个应用程序
List<PackageInfo> packageInfos = packageManager
.getInstalledPackages(PackageManager.GET_ACTIVITIES);
//枚举所有的应用程序信息，从中取出Package和应用程序的Label，中间用“\n”分离
for (PackageInfo packageInfo : packageInfos) {
//LoadLabel方法返回的值就是定义Activity时的android:label属性值
mPackages.add(packageInfo.applicationInfo.loadLabel(packageManager)
+ "\n" + packageInfo.packageName);
}
//创建一个用于操作Package集合的ArrayAdapter对象
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1,
mPackages);
//在ListView控件中显示所有的Package和程序名
setListAdapter(arrayAdapter);
//指定列表项的单击事件方法
getListView().setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
Intent intent = new Intent();
//当单击列表项时，会通过package_name传回Package和Label
intent.putExtra("package_name", mPackages.get(position));
setResult(1, intent);
finish();
}
}
清单文件：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mobile.android.auto.run.application"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.NFC" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".AutoRunApplicationActivity"
android:label="@string/title_activity_auto_run_application"
android:launchMode="singleTop"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".InstalledApplicationListActivity"
android:label="@string/title_activity_installed_application_list"
android:screenOrientation="portrait" />
</application>
</manifest>
通过浏览器自动打开一个网站：
package mobile.android.auto.open.uri;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Intent;
import android.net.Uri;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.widget.Toast;
public class AutoOpenUriActivity extends Activity {
private NfcAdapter nfcAdapter;
private PendingIntent pendingIntent;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_auto_open_uri);
nfcAdapter = NfcAdapter.getDefaultAdapter(this);
pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
getClass()), 0);
}
@Override
public void onResume() {
super.onResume();
if (nfcAdapter != null)
nfcAdapter
.enableForegroundDispatch(this, pendingIntent, null, null);
}
@Override
public void onNewIntent(Intent intent) {
Tag detectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
writeNFCTag(detectedTag);
}
@Override
public void onPause() {
super.onPause();
if (nfcAdapter != null)
nfcAdapter.disableForegroundDispatch(this);
}
public void writeNFCTag(Tag tag) {
if (tag == null) {
Toast.makeText(this, "NFC Tag未建立连接", Toast.LENGTH_LONG).show();
return;
}
// NdefMessage ndefMessage = new NdefMessage(new NdefRecord[]
// { NdefRecord.createUri("http://blog.csdn.net/nokiaguy")});
NdefMessage ndefMessage = new NdefMessage(
new NdefRecord[] {NdefRecord.createUri(Uri
.parse("http://www.baidu.com"))});
int size = ndefMessage.toByteArray().length;
try {
Ndef ndef = Ndef.get(tag);
if (ndef != null) {
ndef.connect();
if (!ndef.isWritable()) {
Toast.makeText(this, "NFC Tag是只读的！", Toast.LENGTH_LONG)
.show();
return;
}
if (ndef.getMaxSize() < size) {
Toast.makeText(this, "NFC Tag的空间不足！", Toast.LENGTH_LONG)
.show();
return;
}
ndef.writeNdefMessage(ndefMessage);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG).show();
} else {
NdefFormatable format = NdefFormatable.get(tag);
if (format != null) {
try {
format.connect();
format.format(ndefMessage);
Toast.makeText(this, "已成功写入数据！", Toast.LENGTH_LONG)
.show();
} catch (Exception e) {
Toast.makeText(this, "写入NDEF格式数据失败！", Toast.LENGTH_LONG)
.show();
}
} else {
Toast.makeText(this, "NFC标签不支持NDEF格式！", Toast.LENGTH_LONG)
.show();
}
}
} catch (Exception e) {
Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
附上官方教程：http://developer.android.com/guide/topics/connectivity/nfc/nfc.html