Android 使用手机NFC的读取NFC标签数据

nfc过滤标签的设置

1 在Manifest添加权限：

在xml里添加nfc的使用权限

1	<uses-permission android:name="android.permission.NFC" />

这个是限制安装权限，只给有nfc功能的手机安装(可选)

1	<uses-feature android:name="android.hardware.nfc" android:required="true" />

2 nfc的过滤方式有以下：

• ACTION_NDEF_DISCOVERED，
• ACTION_TECH_DISCOVERED，
• ACTION_TAG_DISCOVERED三种。过滤器的作用是过滤掉杂质，剩下的就是我们需要的了。这三种过滤方式可同时配置，可以比方成从上到下三层，只要是符合某一层过滤器要求的，过滤完就停止往下一层。

在Activity的filter里面添加对应需要的权限：

ACTION_NDEF_DISCOVERED

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<activity> ...       <intent-filter>         <action android:name="android.nfc.action.NDEF_DISCOVERED" />       intent-filter> ... activity>

在/res/xml(自己新建xml文件夹)下新建一个nfc_tech_filter.xml文件，添加进你需要支持的标签类型。（下面的配置项可多选）。下列示例是支持与NfcA和Ndef技术的NFC标签匹配。

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<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">   <tech-list>     <resources >   <tech-list>          <tech>android.nfc.tech.NfcAtech>                    <tech>android.nfc.tech.Ndeftech>                  tech-list> resources>   tech-list> resources> <activity> ...       <intent-filter>         <action android:name="android.nfc.action.TECH_DISCOVERED" />       intent-filter>         <meta-data         android:name="android.nfc.action.TECH_DISCOVERED"         android:resource="@xml/nfc_tech_filter" />   <meta-data android:name="android.nfc.action.TECH_DISCOVERED"   android:resource="@xml/nfc_tech_filter" /> ... activity> ACTION_TAG_DISCOVERED，可以添加如下权限   <activity> ···       <intent-filter>         <action android:name="android.nfc.action.TAG_DISCOVERED" />       intent-filter> ··· activity>

3 识别标签的顺序

二 nfc读操作（我们读取NEDF数据，其他公交卡类型的数据可以自行研究）

1 初始化nfc工具，判断是否存在nfc和nfc是否打开

2 感应到nfc标签后，读取解析对应nfc类型的标签数据

3 回传显示

package com.example.chenqiuyang.nfcread;

import android.annotation.SuppressLint;
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.NfcEvent;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.MifareUltralight;
import android.os.Bundle;

import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.example.chenqiuyang.nfcread.read.ParsedNdefRecord;
import com.example.chenqiuyang.nfcread.read.TextRecord;

import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.Timer;

/**
 * TODO:功能说明
 *
 * @author: chenqiuyang
 * @date: 2018-07-12 11:18
 */
public class NfcActivity extends Activity {

    private static final String TAG = "NfcActivity";
    private TextView tvNFCMessage;
    private PendingIntent mPendingIntent;
    private NfcAdapter mNfcAdapter;
    private Button btnClean;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfc);
        Log.i(TAG, "onCreate: ");
        btnClean = findViewById(R.id.btn_clean);
        tvNFCMessage = findViewById(R.id.tv_show_nfc);




        //初始化nfc
        mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
        mPendingIntent = PendingIntent.getActivity(this, 0,
                new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
        if (mNfcAdapter == null) {
            Toast.makeText(NfcActivity.this, "nfc is not available", Toast.LENGTH_SHORT).show();
            finish();
            return;
        }


        btnClean.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tvNFCMessage.setText("");
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "onResume: ");
        if (mNfcAdapter != null) { //有nfc功能
            if (mNfcAdapter.isEnabled()) {
                //nfc功能打开了
                //隐式启动
                mNfcAdapter.enableForegroundDispatch(this, mPendingIntent, null, null);
            } else {
                Toast.makeText(NfcActivity.this, "请打开nfc功能", Toast.LENGTH_SHORT).show();
            }
        }
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        Log.i(TAG, "onNewIntent: ");
        setIntent(intent);
        if (mNfcAdapter != null) { //有nfc功能
            if (mNfcAdapter.isEnabled()) {//nfc功能打开了
                resolveIntent(getIntent());
            } else {
                Toast.makeText(NfcActivity.this, "请打开nfc功能", Toast.LENGTH_SHORT).show();
            }
        }
    }


    @Override
    protected void onPause() {
        super.onPause();
        if (mNfcAdapter != null) {
            mNfcAdapter.disableForegroundDispatch(this);
        }
    }

    //初次判断是什么类型的NFC卡
    private void resolveIntent(Intent intent) {
        NdefMessage[] msgs = NfcUtil.getNdefMsg(intent); //重点功能，解析nfc标签中的数据

        if (msgs == null) {
            Toast.makeText(NfcActivity.this, "非NFC启动", Toast.LENGTH_SHORT).show();
        } else {
            setNFCMsgView(msgs);
        }

    }

    /**
     * 显示扫描后的信息
     *
     * @param ndefMessages ndef数据
     */
    @SuppressLint("SetTextI18n")
    private void setNFCMsgView(NdefMessage[] ndefMessages) {
        if (ndefMessages == null || ndefMessages.length == 0) {
            return;
        }

//        tvNFCMessage.setText("Payload:" + new String(ndefMessages[0].getRecords()[0].getPayload()) + "\n");

        Calendar calendar = Calendar.getInstance();
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        tvNFCMessage.append(hour + ":" + minute + "\n");
        List records = NdefMessageParser.parse(ndefMessages[0]);
        final int size = records.size();
        for (int i = 0; i < size; i++) {
            ParsedNdefRecord record = records.get(i);
            tvNFCMessage.append(record.getViewText() + "\n");
        }
    }

}