10、NFC技术：读写NFC标签中的文本数据

代码实现过程如下：

读写NFC标签的纯文本数据.java

  1  import java.nio.charset.Charset;
  2 import java.util.Locale;
  3 
  4 import android.app.Activity;
  5 import android.content.Intent;
  6 import android.nfc.NdefMessage;
  7 import android.nfc.NdefRecord;
  8 import android.nfc.NfcAdapter;
  9 import android.nfc.Tag;
 10 import android.nfc.tech.Ndef;
 11 import android.os.Bundle;
 12 import android.view.View;
 13 import android.widget.TextView;
 14 
 15 /**
 16  * 主 Activity
 17  * 读写NFC标签的纯文本数据
 18  * @author dr
 19  * 
 20  */
 21 public class ReadWriteTextMainActivity extends Activity {
 22     private TextView mInputText;
 23     private String mText;
 24 
 25     @Override
 26     protected void onCreate(Bundle savedInstanceState) {
 27         // TODO Auto-generated method stub
 28         super.onCreate(savedInstanceState);
 29         setContentView(R.layout.activity_read_write_text_main);
 30 
 31         mInputText = (TextView) findViewById(R.id.textview_input_text);
 32     }
 33 
 34     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 35         if (requestCode == 1 && resultCode == 1) {
 36             mText = data.getStringExtra("text");
 37             mInputText.setText(mText);
 38         }
 39     }
 40 
 41     public void onNewIntent(Intent intent) {
 42         // read nfc text
 43         if (mText == null) {
 44             // 显示NFC标签内容
 45             Intent myIntent = new Intent(this, ShowNFCTagContentActivity.class);
 46             myIntent.putExtras(intent);
 47             myIntent.setAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
 48             startActivity(myIntent);
 49 
 50         } else {  // write nfc text
 51             Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
 52             NdefMessage ndefMessage = new NdefMessage(
 53                     new NdefRecord[] { createTextRecord(mText) });
 54             writeTag(ndefMessage, tag);
 55         }
 56     }
 57     
 58     /**
 59      * 将纯文本转换成NdefRecord对象。
 60      * @param text
 61      * @return
 62      */
 63     public NdefRecord createTextRecord(String text) {
 64         // 得到生成语言编码字节数组
 65         byte[] langBytes = Locale.CHINA.getLanguage().getBytes(
 66                 Charset.forName("US-ASCII"));
 67         Charset utfEncoding = Charset.forName("UTF-8");
 68         byte[] textBytes = text.getBytes(utfEncoding);
 69         int utfBit = 0;
 70         // 状态字节
 71         char status = (char) (utfBit + langBytes.length);
 72 
 73         byte[] data = new byte[1 + langBytes.length + textBytes.length];
 74         data[0] = (byte) status;
 75         // 数组拷贝
 76         System.arraycopy(langBytes, 0, data, 1, langBytes.length);
 77         System.arraycopy(textBytes, 0, data, 1 + langBytes.length,
 78                 textBytes.length);
 79 
 80         NdefRecord ndefRecord = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
 81                 NdefRecord.RTD_TEXT, new byte[0], data);
 82         return ndefRecord;
 83     }
 84 
 85     boolean writeTag(NdefMessage ndefMessage, Tag tag) {
 86         try {
 87             Ndef ndef = Ndef.get(tag);
 88             ndef.connect();
 89             ndef.writeNdefMessage(ndefMessage);
 90             return true;
 91         } catch (Exception e) {
 92             // TODO: handle exception
 93         }
 94         return false;
 95     }
 96 
 97     // 向NFC标签写入文本
 98     public void onClick_InputText(View view) {
 99         Intent intent = new Intent(this, InputTextActivity.class);
100         startActivityForResult(intent, 1);
101     }
102 
103 }

读写NFC标签的纯文本数据.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6 
 7     <Button
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         android:onClick="onClick_InputText"
11         android:text="输入要写入文本" />
12 
13     <TextView
14         android:id="@+id/textview_input_text"
15         android:layout_width="match_parent"
16         android:layout_height="wrap_content"
17         android:textSize="16sp" />
18 
19     <TextView
20 
21         android:layout_width="match_parent"
22         android:layout_height="wrap_content"
23         android:layout_marginTop="30dp"
24         android:text="请将NFC标签靠近手机背面读取或写入文本"
25         android:textColor="#F00"
26         android:textSize="16sp" />
27 
28     <ImageView
29         android:layout_width="match_parent"
30         android:layout_height="match_parent"
31         android:src="@drawable/read_nfc_tag" />
32 
33 </LinearLayout>

显示NFC标签内容.java

 1 import cn.eoe.read.write.text.library.TextRecord;
 2 import android.app.Activity;
 3 import android.nfc.NdefMessage;
 4 import android.nfc.NdefRecord;
 5 import android.nfc.NfcAdapter;
 6 import android.nfc.Tag;
 7 import android.nfc.tech.Ndef;
 8 import android.os.Bundle;
 9 import android.os.Parcelable;
10 import android.widget.TextView;
11 
12 
13 /**
14  * 显示NFC标签内容
15  * @author dr
16  *
17  */
18 public class ShowNFCTagContentActivity extends Activity {
19 
20     private TextView mTagContent;
21     private Tag mDetectedTag;   // 传递过来的NFC的一个TAG对象
22     private String mTagText;
23 
24     @Override
25     protected void onCreate(Bundle savedInstanceState) {
26         // TODO Auto-generated method stub
27         super.onCreate(savedInstanceState);
28         setContentView(R.layout.activity_show_nfctag_content);
29         mTagContent = (TextView) findViewById(R.id.textview_tag_content);
30 
31         mDetectedTag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
32 
33         Ndef ndef = Ndef.get(mDetectedTag);
34 
35         mTagText = ndef.getType() + "
max size:" + ndef.getMaxSize()
36                 + "bytes

";
37 
38         readNFCTag();
39 
40         mTagContent.setText(mTagText);
41     }
42 
43     /**
44      * 
45      */
46     private void readNFCTag() {
47         if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
48             Parcelable[] rawMsgs = getIntent().getParcelableArrayExtra(
49                     NfcAdapter.EXTRA_NDEF_MESSAGES);
50             NdefMessage msgs[] = null;
51             int contentSize = 0;
52             if (rawMsgs != null) {
53                 msgs = new NdefMessage[rawMsgs.length];
54                 for (int i = 0; i < rawMsgs.length; i++) {
55                     msgs[i] = (NdefMessage) rawMsgs[i];
56                     contentSize += msgs[i].toByteArray().length;
57                 }
58             }
59             try {
60                 if (msgs != null) {
61                     NdefRecord record = msgs[0].getRecords()[0];
62                     TextRecord textRecord = TextRecord.parse(record);
63                     mTagText += textRecord.getText() + "

text
"
64                             + contentSize + " bytes";
65                 }
66             } catch (Exception e) {
67                 // TODO: handle exception
68             }
69         }
70     }
71 }

显示NFC标签内容.xml

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent"
 4     android:orientation="vertical" >
 5 
 6     <TextView
 7         android:id="@+id/textview_tag_content"
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         android:textSize="16sp" android:layout_margin="6dp" />
11 
12 </LinearLayout>

向NFC标签写入文本.java

 1 import android.app.Activity;
 2 import android.content.Intent;
 3 import android.os.Bundle;
 4 import android.view.View;
 5 import android.widget.EditText;
 6 
 7 /**
 8  * 向NFC标签写入文本
 9  * 
10  * @author dr
11  * 
12  */
13 public class InputTextActivity extends Activity {
14 
15     private EditText mTextTag;
16 
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_input_text);
21         mTextTag = (EditText) findViewById(R.id.edittext_text_tag);
22     }
23 
24     public void onClick_OK(View view) {
25         Intent intent = new Intent();
26         intent.putExtra("text", mTextTag.getText().toString());
27         setResult(1, intent);
28         finish();
29 
30     }
31 }

向NFC标签写入文本.xml

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6 
 7     <TextView
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         
11         android:text="请输入要写入的文本" android:textSize="16sp" />
12 
13     <EditText
14         android:layout_marginTop="10dp"
15         android:id="@+id/edittext_text_tag"
16         android:layout_width="match_parent"
17         android:layout_height="wrap_content" />
18 
19     <Button
20         android:layout_width="match_parent"
21         android:layout_height="wrap_content"    
22         android:onClick="onClick_OK"
23         android:text="确定" />
24 
25 </LinearLayout>

 1 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 2     package="cn.eoe.read.write.text"
 3     android:versionCode="1"
 4     android:versionName="1.0" >
 5 
 6     <uses-sdk
 7         android:minSdkVersion="15"
 8         android:targetSdkVersion="15" />
 9 
10     <uses-permission android:name="android.permission.NFC" />
11 
12     <application
13         android:icon="@drawable/ic_launcher"
14         android:label="@string/app_name"
15         android:theme="@style/AppTheme" >
16         <activity
17             android:name=".ReadWriteTextMainActivity"
18             android:label="读写NFC标签的纯文本数据"
19             android:launchMode="singleTask" >
20             <intent-filter>
21                 <action android:name="android.intent.action.MAIN" />
22                 <category android:name="android.intent.category.LAUNCHER" />
23             </intent-filter>
24             <intent-filter>
25                 <action android:name="android.nfc.action.NDEF_DISCOVERED" />
26                 <category android:name="android.intent.category.DEFAULT" />
27                 <data android:mimeType="text/plain" />
28             </intent-filter>
29         </activity>
30         <activity
31             android:name=".ShowNFCTagContentActivity"
32             android:label="显示NFC标签内容"
33             android:launchMode="singleTask" />
34 
35         <activity
36             android:name=".InputTextActivity"
37             android:label="向NFC标签写入文本" />
38 
39     </application>
40 
41 </manifest>

DEMO:下载地址：http://download.csdn.net/detail/androidsj/7678947