android rfid 的开发

谢潭生

2016-04-28

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昨天同事找我帮忙看看 rfid 开发的时候，一扫描就直接弹出activity的问题。

网上也有蛮多例子，但是能直接拿来参考写实际项目的没几个，系统提供的demo呢，一扫描标签就弹出activity，也是开发中不想要的。于是进入苦逼模式，进过分析和翻资料、百度、终于解决了。下面是代码：

先看项目图片，我是直接用demo修改的：

android rfid 的开发

1、清单文件：

需求添加权限啦什么，自己看啊，

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.nl.nfcdemo"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="15" />
    <!-- 添加nfc权限 -->
    <uses-permission android:name="android.permission.NFC" />

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.nl.nfcdemo.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
    </application>

</manifest>

2、MainAcivity类。

package com.nl.nfcdemo;

import android.app.Activity;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.IntentFilter.MalformedMimeTypeException;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.NfcV;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private final String ACTION_NAME = "android.nfc.action.TECH_DISCOVERED";  
    NfcAdapter nfcAdapter;
    TextView   promt;
    private PendingIntent mPendingIntent;
    private IntentFilter [] mIntentFilters;
    private String[][] mTechLists;
    
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate (savedInstanceState);
        setContentView (R.layout.activity_main);
        
        promt = (TextView) findViewById (R.id.promt);
         
        // 获取默认的NFC控制器
        nfcAdapter = NfcAdapter.getDefaultAdapter (this);
        if (nfcAdapter == null) {
            promt.setText ("设备不支持NFC！");
            finish ();
            return;
        }
        if (!nfcAdapter.isEnabled ()) {
            promt.setText ("请在系统设置中先启用NFC功能！");
            finish ();
            return;
        }
        
        initNFC();
    }
    
    
    

    /**
     *@Description: 初始化
     *@Author:杨攀
     *@Since: 2016年4月27日下午5:38:15
     */
    private void initNFC(){
        //绑定Intent
        Intent mIntent = new Intent (ACTION_NAME);
        mPendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
        
        IntentFilter techFilter = new IntentFilter (nfcAdapter.ACTION_TECH_DISCOVERED);
        try {
            techFilter.addDataType ("text/plain");
            mIntentFilters = new IntentFilter[]{techFilter};
        } catch (MalformedMimeTypeException e) {
            e.printStackTrace();
        }
        
        mTechLists  = new String[][] { 
                new String[] {"android.nfc.tech.NfcA"},
                new String[]{"android.nfc.tech.NfcB"},
                new String[]{"android.nfc.tech.NfcF"},
                new String[]{"android.nfc.tech.NfcV"},
                new String[]{"android.nfc.tech.Ndef"},
                new String[]{"android.nfc.tech.NdefFormatable"},
                new String[]{"android.nfc.tech.IsoDep"},
                new String[]{"android.nfc.tech.MifareClassic"},
                new String[]{"android.nfc.tech.MifareUltralight"}
                };
    }

    /**
     *@Description: 拦截系统的 intent, 然后触发读写操作
     *@Author:杨攀
     *@Since: 2016年4月27日下午5:08:20
     *@param intent
     */
    @Override
    protected void onNewIntent(Intent intent){
        super.onNewIntent (intent);
        // 得到是否检测到ACTION_TECH_DISCOVERED触发
        if (NfcAdapter.ACTION_TECH_DISCOVERED.equals (intent.getAction ())) {
            // 处理该intent
            processIntent (intent);
        }
    }


    /**
     *@Description: 注册 意图 
     *@Author:杨攀
     *@Since: 2016年4月27日下午5:34:21
     */
    @Override
    protected void onResume(){
        super.onResume ();
        nfcAdapter.enableForegroundDispatch (this, mPendingIntent, mIntentFilters, mTechLists);
    }

    /**
     *@Description: 窗口关闭的时候，注销意图
     *@Author:杨攀
     *@Since: 2016年4月27日下午5:34:35
     */
    @Override
    protected void onPause(){
        super.onPause ();
        //注销注册
        nfcAdapter.disableForegroundDispatch(this); 
    }
    
    @Override
    protected void onDestroy(){
        super.onDestroy ();
    }
    
    // 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 ();
    }

    /**
     * Parses the NDEF Message from the intent and prints to the TextView
     */
    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;
        // 读取TAG
        MifareClassic mfc = MifareClassic.get (tagFromIntent);
        String metaInfo = "本标签的UID为" + Coverter.getUid (intent) + "\n";
        if (mfc != null) {
            try {
                // Enable I/O operations to the tag from this TagTechnology
                // object.
                mfc.connect ();
                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 () + "B\n";
                for ( int j = 0 ; j < sectorCount ; j++ ) {
                    // Authenticate a sector with key A.
                    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";
                    }
                }
            } catch (Exception e) {
                e.printStackTrace ();
            }
        }
        promt.setText (metaInfo);
    }

}

经过运行，可以。我在上传项目的压缩包。需要的自行下载。

android