android nfc写入应用程序包名与网址 自动打开应用程序与网址

安卓手机大部分手机提供了NFC芯片 可以根据NFC传递数据 NFC卡与手机 手机与手机数据等交互 非常好的功能，这篇文章教大家如何向NFC卡或标签写入功能。

DEMO下载地址http://download.csdn.net/detail/u012303938/9243233

用法 ： 点击包名 将NFC标签靠近手机后置摄像头附近即可

效果 ： 第一次靠近 将自己的应用程序包名写入nfc标签，第二次靠近 会自动打开自己写入的应该程序。

注意几点：

1、清单文件要加上权限 activity使用singleTop启动模式

2、NFC主要用到 NdfcAdapter与PendingIntent去建立联系

3、Tag tag=intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);方法去取nfc里的资源

代码如下：

package com.example.autonfc;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.app.PendingIntent;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.NfcManager;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnItemClickListener{
private List<String> list;
private NfcAdapter adapters;
private PendingIntent intent;
private String packageName;
private ListView listView1;
private NdefMessage ndefMessage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView1=(ListView) findViewById(R.id.listView1);
list=new ArrayList<String>();
PackageManager manager=getPackageManager();
List<PackageInfo> PackageInfos= manager.getInstalledPackages(PackageManager.GET_ACTIVITIES);
for(PackageInfo info: PackageInfos){
list.add(info.applicationInfo.loadLabel(manager)+"\n"+
info.packageName);
}
ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, list);
listView1.setAdapter(adapter);
listView1.setOnItemClickListener(this);

adapters=NfcAdapter.getDefaultAdapter(this);
intent=PendingIntent.getActivity(this, 0, new Intent(this,getClass()), 0);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// TODO Auto-generated method stub
packageName=list.get(position);
Toast.makeText(this, "选择了"+packageName, Toast.LENGTH_SHORT).show();

}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
if(adapters!=null){
adapters.enableForegroundDispatch(this, intent, null, null);
}

}

@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
if(adapters!=null){
adapters.disableForegroundDispatch(this);
}

}
@Override
protected void onNewIntent(Intent intent) {
// TODO Auto-generated method stub
super.onNewIntent(intent);
Toast.makeText(this, "执行了", Toast.LENGTH_SHORT).show();
Tag tag=intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
if(packageName==null){
Toast.makeText(this, "请选择包名", Toast.LENGTH_SHORT).show();
return;
}
onWriteNFC(tag);

}

public void onWriteNFC(final Tag tag){
if(tag==null){
Toast.makeText(this, "没有找到TAG", Toast.LENGTH_SHORT).show();
return;
}
Toast.makeText(this, "tag有值", Toast.LENGTH_SHORT).show();
ndefMessage=new NdefMessage(new NdefRecord[]{NdefRecord.createApplicationRecord(packageName)});
//写入一个网址
//ndefMessage=new NdefMessage(new NdefRecord[]{NdefRecord.createUri(Uri.parse("http://www.baidu.com"))});

int size=ndefMessage.toByteArray().length;
Toast.makeText(this, "要写入信息的长度"+size, Toast.LENGTH_SHORT).show();
Ndef ndef=Ndef.get(tag);

if(ndef!=null){
try {
ndef.connect();
if(!ndef.isWritable()){
Toast.makeText(this, "NFC卡不支持写入", Toast.LENGTH_SHORT).show();
return;
}
if(ndef.getMaxSize()<size){
Toast.makeText(this, "NFC卡内存不够", Toast.LENGTH_SHORT).show();
return;
}
ndef.writeNdefMessage(ndefMessage);
Toast.makeText(this, "NFC卡写入成功", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
Toast.makeText(this, "此卡不是ndef格式", Toast.LENGTH_SHORT).show();
new AlertDialog.Builder(this).setTitle("是否格式化成ndef格式，并写入包名")
.setPositiveButton("是", new AlertDialog.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
NdefFormatable  formatable=NdefFormatable.get(tag);
if(formatable==null){
Toast.makeText(MainActivity.this, "此卡不能ndef格式化",
Toast.LENGTH_SHORT).show();
return;
}
try {
formatable.connect();
formatable.format(ndefMessage);
Toast.makeText(MainActivity. this, "NFC卡写入成功", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).setNegativeButton("否", null).create().show();
}
}

}