10、NFC技术：读写NFC标签中的文本数据

2023-08-21 21:40:28

代码实现过程如下：

读写NFC标签的纯文本数据.java

  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.os.Bundle;

 import android.view.View;

 import android.widget.TextView;

 /**

  * 主 Activity

  * 读写NFC标签的纯文本数据

  * @author dr

  *

  */

 public class ReadWriteTextMainActivity extends Activity {

     private TextView mInputText;

     private String mText;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         // TODO Auto-generated method stub

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_read_write_text_main);

         mInputText = (TextView) findViewById(R.id.textview_input_text);

     }

     protected void onActivityResult(int requestCode, int resultCode, Intent data) {

         if (requestCode == 1 && resultCode == 1) {

             mText = data.getStringExtra("text");

             mInputText.setText(mText);

         }

     }

     public void onNewIntent(Intent intent) {

         // read nfc text

         if (mText == null) {

             // 显示NFC标签内容

             Intent myIntent = new Intent(this, ShowNFCTagContentActivity.class);

             myIntent.putExtras(intent);

             myIntent.setAction(NfcAdapter.ACTION_NDEF_DISCOVERED);

             startActivity(myIntent);

         } else {  // write nfc text

             Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

             NdefMessage ndefMessage = new NdefMessage(

                     new NdefRecord[] { createTextRecord(mText) });

             writeTag(ndefMessage, tag);

         }

     }

     /**

      * 将纯文本转换成NdefRecord对象。

      * @param text

      * @return

      */

     public NdefRecord createTextRecord(String text) {

         // 得到生成语言编码字节数组

         byte[] langBytes = Locale.CHINA.getLanguage().getBytes(

                 Charset.forName("US-ASCII"));

         Charset utfEncoding = Charset.forName("UTF-8");

         byte[] textBytes = text.getBytes(utfEncoding);

         int utfBit = 0;

         // 状态字节

         char status = (char) (utfBit + langBytes.length);

         byte[] data = new byte[1 + langBytes.length + textBytes.length];

         data[0] = (byte) status;

         // 数组拷贝

         System.arraycopy(langBytes, 0, data, 1, langBytes.length);

         System.arraycopy(textBytes, 0, data, 1 + langBytes.length,

                 textBytes.length);

         NdefRecord ndefRecord = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,

                 NdefRecord.RTD_TEXT, new byte[0], data);

         return ndefRecord;

     }

     boolean writeTag(NdefMessage ndefMessage, Tag tag) {

         try {

             Ndef ndef = Ndef.get(tag);

             ndef.connect();

             ndef.writeNdefMessage(ndefMessage);

             return true;

         } catch (Exception e) {

             // TODO: handle exception

         }

         return false;

     }

     // 向NFC标签写入文本

     public void onClick_InputText(View view) {

         Intent intent = new Intent(this, InputTextActivity.class);

         startActivityForResult(intent, 1);

     }

 }

读写NFC标签的纯文本数据.xml

 <?xml version="1.0" encoding="utf-8"?>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical" >

     <Button

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:onClick="onClick_InputText"

         android:text="输入要写入文本" />

     <TextView

         android:id="@+id/textview_input_text"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:textSize="16sp" />

     <TextView

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:layout_marginTop="30dp"

         android:text="请将NFC标签靠近手机背面读取或写入文本"

         android:textColor="#F00"

         android:textSize="16sp" />

     <ImageView

         android:layout_width="match_parent"

         android:layout_height="match_parent"

         android:src="@drawable/read_nfc_tag" />

 </LinearLayout>

显示NFC标签内容.java

 import cn.eoe.read.write.text.library.TextRecord;

 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;

 /**

  * 显示NFC标签内容

  * @author dr

  *

  */

 public class ShowNFCTagContentActivity extends Activity {

     private TextView mTagContent;

     private Tag mDetectedTag;   // 传递过来的NFC的一个TAG对象

     private String mTagText;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         // TODO Auto-generated method stub

         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() + "\nmax size:" + 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 msgs[] = null;

             int contentSize = 0;

             if (rawMsgs != null) {

                 msgs = new NdefMessage[rawMsgs.length];

                 for (int i = 0; i < rawMsgs.length; i++) {

                     msgs[i] = (NdefMessage) rawMsgs[i];

                     contentSize += msgs[i].toByteArray().length;

                 }

             }

             try {

                 if (msgs != null) {

                     NdefRecord record = msgs[0].getRecords()[0];

                     TextRecord textRecord = TextRecord.parse(record);

                     mTagText += textRecord.getText() + "\n\ntext\n"

                             + contentSize + " bytes";

                 }

             } catch (Exception e) {

                 // TODO: handle exception

             }

         }

     }

 }

显示NFC标签内容.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical" >

     <TextView

         android:id="@+id/textview_tag_content"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:textSize="16sp" android:layout_margin="6dp" />

 </LinearLayout>

向NFC标签写入文本.java

 import android.app.Activity;

 import android.content.Intent;

 import android.os.Bundle;

 import android.view.View;

 import android.widget.EditText;

 /**

  * 向NFC标签写入文本

  *

  * @author dr

  *

  */

 public class InputTextActivity extends Activity {

     private EditText mTextTag;

     @Override

     protected 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();

     }

 }

向NFC标签写入文本.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     xmlns:tools="http://schemas.android.com/tools"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical" >

     <TextView

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:text="请输入要写入的文本" android:textSize="16sp" />

     <EditText

         android:layout_marginTop="10dp"

         android:id="@+id/edittext_text_tag"

         android:layout_width="match_parent"

         android:layout_height="wrap_content" />

     <Button

         android:layout_width="match_parent"

         android:layout_height="wrap_content"

         android:onClick="onClick_OK"

         android:text="确定" />

 </LinearLayout>

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"

     package="cn.eoe.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>

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

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