NFC(7)向NFC硬件写入数据的两个示例(nfc硬件启动android应用,nfc硬件打开uri)

向NFC标签写入数据基本步骤

1,获取Tag对象

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

2,判断NFC标签的数据类型（通过Ndef.get方法）

　　Ndef ndef = Ndef.get(tag);

3,NFC开始连接

　　ndef.connect();

4,建NdefMessage数据,然后将它写入数据
　　ndef.writeNdefMessage(ndefMessage);

示例1: nfc标签设备启动android应用

 import android.app.Activity;
 import android.app.PendingIntent;
 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.Button;
 import android.widget.Toast;

 public class RunApplicationActivity extends Activity {

     private Button mSelectAutoRunApplication;
     private String mPackageName;

     private NfcAdapter mNfcAdapter;//用来NFC通信
     private PendingIntent mPendingIntent;//用来封装当前窗口

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_auto_run_application);

         mSelectAutoRunApplication = (Button) findViewById(R.id.button_select_auto_run_application);

         mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
         mPendingIntent = PendingIntent.getActivity(this, , new Intent(this,
                 getClass()), );

     }
     //从另一个aty中取出数据.
     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data)
     {
         if (resultCode == )
         {
             mSelectAutoRunApplication.setText(data.getExtras().getString(
                     "package_name"));
             String temp = mSelectAutoRunApplication.getText().toString();
             mPackageName = temp.substring(temp.indexOf("\n") + );

         }

     }
     //由于在manifest.xml中指定当前aty主singleTop,所以startactivity时 onCreate只被调用一次.
     //但是onNewIntent在startactivity会被调用
     @Override
     public void onNewIntent(Intent intent) {
         if (mPackageName == null)
             return;

         //第1步,取得NFC 标签
         Tag detectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

         writeNFCTag(detectedTag);//自写的成员函数
     }

     //第4种 过滤方法的开始函数,要比3种过滤方法优先级高
     @Override
     public void onResume() {
         super.onResume();
         //在Resume时让当前窗口优先处理nfc数据
         if (mNfcAdapter != null){
             mNfcAdapter.enableForegroundDispatch(this, mPendingIntent, null,
                     null);
         }
     }
     //第4种 过滤方法结束函数,要比3种过滤方法优先级高
     @Override
     public void onPause() {
         super.onPause();
         //在onPause时取消让当前窗口优先处理nfc数据
         if (mNfcAdapter != null)
             mNfcAdapter.disableForegroundDispatch(this);
     }
     public void onClick_SelectAutoRunApplication(View view)
     {
         Intent intent = new Intent(this, InstalledApplicationListActivity.class);
         startActivityForResult(intent, );
     }
     //向nfc标签写入数据的函数
     public void writeNFCTag(Tag tag) {
         if (tag == null) {
             return;
         }
         try {
             //第2步,判断NFC标签的数据类型（通过Ndef.get方法）
             Ndef ndef = Ndef.get(tag);

             if(ndef != null )
             {
                 //第3步,NFC开始连接
                 ndef.connect();

                 if(!ndef.isWritable())//标签是否可写.
                 {
                     return;
                 }
                 //第4步,准备数据
                 //一个NdefMessage 中可有多个NdefRecord,它们之间关系类似table与record
                 NdefMessage ndefMessage = new NdefMessage(
                         new NdefRecord[] { NdefRecord
                                 .createApplicationRecord(mPackageName) });
                 int size = ndefMessage.toByteArray().length;
                 if(ndef.getMaxSize() < size)
                 {
                     return;
                 }
                 //第5步,把数据写入到nfc标签中.
                 ndef.writeNdefMessage(ndefMessage);
                 //第6步,写入成功提示
                 Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
             }
         } catch (Exception e) {
             //有可能异常
             e.printStackTrace();
         }
     }
 }

manifest.xml

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="c.e.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=".RunApplicationActivity"
             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>

示例2: nfc标签设备打开一个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, , new Intent(this,
                 getClass()), );

     }

     @Override
     public void onResume() {
         super.onResume();
         if (nfcAdapter != null)
             nfcAdapter
                     .enableForegroundDispatch(this, pendingIntent, null, null);
     }

     @Override
     public void onNewIntent(Intent intent) {
         //第1步,取得NFC 标签
         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) {
             return;
         }
         Uri uri = Uri.parse("http://www.bing.com");
         NdefMessage ndefMessage = new NdefMessage(
                 new NdefRecord[] { NdefRecord.createUri(uri) });
         int size = ndefMessage.toByteArray().length;
         try{
             Ndef ndef = Ndef.get(tag);

             if (ndef != null){// 已经格式化
                 ndef.connect();
                 if (!ndef.isWritable()) {
                     return;
                 }
                 if (ndef.getMaxSize() < size) {
                     return;
                 }
                 ndef.writeNdefMessage(ndefMessage);
                 Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
             } else {// 标签未格式化
                     // 第1步,获取NdefFormatable
                 NdefFormatable format = NdefFormatable.get(tag);
                 if (format != null){// 可以格式化
                     // 第2步,连接
                     format.connect();
                     // 第3步,格式化同时把数据写入到标签中.
                     format.format(ndefMessage);
                     Toast.makeText(this, "ok", Toast.LENGTH_LONG).show();
                 } else {// 不可格式化
                     Toast.makeText(this, "formating is failed",
                             Toast.LENGTH_LONG).show();
                 }
             }

         } catch (Exception e) {
             e.printStackTrace();
         }
     }

 }