Android系统NFC读写简介

ackage org.reno;

import android.app.Activity;
import android.content.Intent;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.os.Bundle;
import android.widget.TextView;

public class Beam extends Activity {
NfcAdapter nfcAdapter;
TextView promt;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
promt = (TextView) findViewById(R.id.promt);
// 获取默认的NFC控制器

NfcAdapter //相当于一个NFC适配器，类似于电脑装了网络适配器才能上网，手机装了NfcAdapter才能发起NFC通信。
nfcAdapter = NfcAdapter.getDefaultAdapter(this);
if (nfcAdapter == null) { //如果NFC不存在
promt.setText(“设备不支持NFC！”);
finish();
return;
}
if (!nfcAdapter.isEnabled()) {//如果NFC未开启
promt.setText(“请在系统设置中先启用NFC功能！”);
finish();
return;
}
}

@Override
protected void onResume() {
super.onResume();
//得到是否检测到ACTION_TECH_DISCOVERED触发
if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(getIntent().getAction())) {
//处理该intent
processIntent(getIntent());
}
}
//字符序列转换为16进制字符串
private String bytesToHexString(byte[] src) {
StringBuilder stringBuilder = new StringBuilder(“0x”);
if (src == null || src.length <= 0) {
return null;
}
char[] buffer = new char[2];
for (int i = 0; i < src.length; i++) {
buffer[0] = Character.forDigit((src[i] >>> 4) & 0x0F, 16);
buffer[1] = Character.forDigit(src[i] & 0x0F, 16);
System.out.println(buffer);
stringBuilder.append(buffer);
}
return stringBuilder.toString();
}

//系统来检测到NFC , 将其封装成Tag类，存放到Intent的NfcAdapter.EXTRA_TAG Extra 数据包中，
//使用MifareClassic.get(Tag) 获取对象的 MifareClassic类。

//取出NFC中的数据
 private void processIntent(Intent intent) {
 //取出封装在intent中的TAG
 Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
 for (String tech : tagFromIntent.getTechList()) {
 System.out.println(tech);
 }
 boolean auth = false;

 MifareClassic mfc = MifareClassic.get(tagFromIntent);
 try {
 String metaInfo = “”;
 //Enable I/O operations to the tag from this TagTechnology object.
 mfc.connect();
//因此读写Mifare Tag //首先需要有正确的Key值（起到保护的作用），如果鉴权成功，然后才可以读写该区数据。
 int type = mfc.getType();//获取TAG的类型
 int sectorCount = mfc.getSectorCount();//获取TAG中包含的扇区数
 String typeS = “”;
 switch (type) {
 case MifareClassic.TYPE_CLASSIC:
 typeS = “TYPE_CLASSIC”;
 break;
 case MifareClassic.TYPE_PLUS:
 typeS = “TYPE_PLUS”;
 break;
 case MifareClassic.TYPE_PRO:
 typeS = “TYPE_PRO”;
 break;
 case MifareClassic.TYPE_UNKNOWN:
 typeS = “TYPE_UNKNOWN”;
 break;
 }
 metaInfo += “卡片类型：” + typeS + “n共” + sectorCount + “个扇区n共”
 + mfc.getBlockCount() + “个块n存储空间: ” + mfc.getSize() + “Bn”;
 for (int j = 0; j < sectorCount; j++) {
 //读写Mifare Tag 首先需要有正确的Key值（起到保护的作用），如果鉴权成功：
 auth = mfc.authenticateSectorWithKeyA(j,
 MifareClassic.KEY_DEFAULT);
 int bCount;
 int bIndex;
if (auth) {
 metaInfo += “Sector ” + j + “:验证成功n”;
 // 读取扇区中的块
 bCount = mfc.getBlockCountInSector(j);
 bIndex = mfc.sectorToBlock(j);
 for (int i = 0; i < bCount; i++) {
 byte[] data = mfc.readBlock(bIndex);
 metaInfo += “Block ” + bIndex + ” : ”
 + bytesToHexString(data) + “n”;
 bIndex++;
 }
 } else {
 metaInfo += “Sector ” + j + “:验证失败n”;
 }
 }
 promt.setText(metaInfo);
 } catch (Exception e) {
 e.printStackTrace();
 }
 }