12、NFC技术：读写NFC标签中的Uri数据

功能实现，如下代码所示：

读写NFC标签的Uri 主Activity

 import cn.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.os.Bundle;
 import android.view.View;
 import android.widget.TextView;
 import android.widget.Toast;

 /**
  * 读写NFC标签的Uri
  * @author dr
  *
  */
 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);
         }
     }

     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 {  // write nfc
             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;
         for (Byte b : UriRecord.URI_PREFIX_MAP.keySet()) {
             String prefixStr = UriRecord.URI_PREFIX_MAP.get(b).toLowerCase();
             if ("".equals(prefixStr))
                 continue;
             if (uriStr.toLowerCase().startsWith(prefixStr)) {
                 prefix = b;
                 uriStr = uriStr.substring(prefixStr.length());
                 break;
             }
         }
         byte[] data = new byte[1 + uriStr.length()];
         data[0] = prefix;
         System.arraycopy(uriStr.getBytes(), 0, data, 1, uriStr.length());

         NdefRecord record = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
                 NdefRecord.RTD_URI, new byte[0], data);
         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()) {
                     return false;
                 }
                 if (ndef.getMaxSize() < size) {
                     return false;
                 }
                 ndef.writeNdefMessage(message);
                 Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
                 return true;
             }
         } catch (Exception e) {
             // TODO: handle exception
         }
         return false;
     }
 }

读写NFC标签的Uri 主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_SelectUri"
         android:text="选择Uri" />

     <TextView
         android:id="@+id/textview_uri"
         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Uri"
         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URI列表Activity

 import android.app.ListActivity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;

 /**
  * 显示URI列表
  * @author dr
  *
  */
 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();
     }

 }

显示NFC标签内容Activity

 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;
 import cn.read.write.uri.library.UriRecord;

 /**
  * 显示NFC标签内容
  * @author dr
  *
  */
 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 max 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 ndefMessage = null;

             int contentSize = 0;
             if (rawMsgs != null) {
                 if (rawMsgs.length > 0) {
                     ndefMessage = (NdefMessage) rawMsgs[0];
                     contentSize = ndefMessage.toByteArray().length;
                 } else {
                     return;
                 }
             }
             try {
                 NdefRecord ndefRecord = ndefMessage.getRecords()[0];
                 UriRecord uriRecord = UriRecord.parse(ndefRecord);
                 mTagText += uriRecord.getUri().toString() + "\n\nUri\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:layout_margin="6dp"
         android:textSize="16sp" />

 </LinearLayout>

AndroidManifest.xml

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="cn.eoe.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>
             <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="cn.eoe.read.write.uri.ShowNFCTagContentActivity"
             android:label="显示NFC标签内容" />
         <activity
             android:name="cn.eoe.read.write.uri.UriListActivity"
             android:label="选择Uri" />
     </application>

 </manifest>

DEMO下载地址：http://download.csdn.net/detail/androidsj/7680247