NFC读写实例

于 2013-09-23 15:20:00 发布
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文章标签： 移动开发 java
原文链接：http://www.cnblogs.com/sy171822716/p/3334925.html
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本文详细介绍了一款基于Android平台的NFC应用开发实例，包括读取和写入NFC标签的具体实现。通过源码分析，展示了如何使用NdefMessage和NdefRecord进行数据交换，以及如何处理不同类型的NFC标签。

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package com.sy.nfc.test;

import java.io.IOException;

import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.nfc.tech.NfcA;
import android.os.Bundle;
import android.os.Parcelable;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.PendingIntent;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

/**
 * 
 * @author shenyang
 * @see
 * @des
 * 
 *      Nfc 标签的扫描
 * 
 * 
 */
@SuppressLint("NewApi")
public class ReadTag extends Activity {
    private NfcAdapter nfcAdapter;
    private TextView resultText;
    private PendingIntent pendingIntent;
    private IntentFilter[] mFilters;
    private String[][] mTechLists;
    private Button mJumpTagBtn;
    private boolean isFirst = true;

    @SuppressLint("NewApi")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 获取nfc适配器，判断设备是否支持NFC功能
        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        if (nfcAdapter == null) {
            Toast.makeText(this, getResources().getString(R.string.no_nfc),
                    Toast.LENGTH_SHORT).show();
            finish();
            return;
        } else if (!nfcAdapter.isEnabled()) {
            Toast.makeText(this, getResources().getString(R.string.open_nfc),
                    Toast.LENGTH_SHORT).show();
            finish();
            return;
        }
        setContentView(R.layout.read_tag);
        // 显示结果Text
        resultText = (TextView) findViewById(R.id.resultText);
        // 写入标签按钮
        mJumpTagBtn = (Button) findViewById(R.id.jump);
        mJumpTagBtn.setOnClickListener(new WriteBtnOnClick());

        pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
                getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
        IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
        ndef.addCategory("*/*");
        mFilters = new IntentFilter[] { ndef };// 过滤器
        mTechLists = new String[][] {
                new String[] { MifareClassic.class.getName() },
                new String[] { NfcA.class.getName() } };// 允许扫描的标签类型

    }

    @SuppressLint("NewApi")
    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        nfcAdapter.enableForegroundDispatch(this, pendingIntent, mFilters,
                mTechLists);
        if (isFirst) {
            if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(getIntent().getAction())) {
                String result = processIntent(getIntent());
                resultText.setText(result);
            }
            isFirst = false;
        }

    }

    @Override
    protected void onNewIntent(Intent intent) {
        // TODO Auto-generated method stub
        super.onNewIntent(intent);
        if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(intent.getAction())) {
            String result = processIntent(intent);
            resultText.setText(result);
        }
    }

    /**
     * 获取tab标签中的内容
     * 
     * @param intent
     * @return
     */
    @SuppressLint("NewApi")
    private String processIntent(Intent intent) {
        Parcelable[] rawmsgs = intent
                .getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
        NdefMessage msg = (NdefMessage) rawmsgs[0];
        NdefRecord[] records = msg.getRecords();
        String resultStr = new String(records[0].getPayload());
        return resultStr;
    }

    /**
     * 按钮点击事件
     * 
     * @author shenyang
     * 
     */
    class WriteBtnOnClick implements OnClickListener {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            switch (v.getId()) {
            case R.id.jump:
                Intent intent = new Intent(ReadTag.this, WriteTag.class);
                startActivity(intent);
            default:
                break;
            }
        }

    }

}
读标签内容代码展开 
package com.sy.nfc.test;

import java.io.IOException;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.PendingIntent;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.nfc.tech.NfcA;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

/**
 * 写入标签
 * 
 * @warn：弹出dialog 允许写入
 * @author shenyang
 * 
 */
@SuppressLint("NewApi")
public class WriteTag extends Activity {

    private IntentFilter[] mWriteTagFilters;
    private NfcAdapter nfcAdapter;
    PendingIntent pendingIntent;
    String[][] mTechLists;
    Button writeBtn;
    boolean isWrite = false;
    EditText mContentEditText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.write_tag);
        writeBtn = (Button) findViewById(R.id.writeBtn);
        writeBtn.setOnClickListener(new WriteOnClick());
        mContentEditText = (EditText) findViewById(R.id.content_edit);
        // 获取nfc适配器，判断设备是否支持NFC功能
        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        if (nfcAdapter == null) {
            Toast.makeText(this, getResources().getString(R.string.no_nfc),
                    Toast.LENGTH_SHORT).show();
            finish();
            return;
        } else if (!nfcAdapter.isEnabled()) {
            Toast.makeText(this, getResources().getString(R.string.open_nfc),
                    Toast.LENGTH_SHORT).show();
            finish();
            return;
        }
        pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
                getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
        // 写入标签权限
        IntentFilter writeFilter = new IntentFilter(
                NfcAdapter.ACTION_TECH_DISCOVERED);
        mWriteTagFilters = new IntentFilter[] { writeFilter };
        mTechLists = new String[][] {
                new String[] { MifareClassic.class.getName() },
                new String[] { NfcA.class.getName() } };// 允许扫描的标签类型

    }

    /**
     * 写入标签按钮点击事件监听
     * 
     * @author shenyang
     * 
     */
    class WriteOnClick implements OnClickListener {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            isWrite = true;
            AlertDialog.Builder builder = new AlertDialog.Builder(WriteTag.this)
                    .setTitle("请将标签靠近！");
            builder.setNegativeButton("确定",
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            // TODO Auto-generated method stub
                            dialog.dismiss();
                            mContentEditText.setText("");
                            isWrite = false;
                            WriteTag.this.finish();
                        }
                    });
            builder.setPositiveButton("取消",
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            // TODO Auto-generated method stub
                            dialog.dismiss();
                            isWrite = false;
                        }
                    });
            builder.create();
            builder.show();
        }
    }

    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        nfcAdapter.enableForegroundDispatch(this, pendingIntent,
                mWriteTagFilters, mTechLists);
    }

    // 写入模式时，才执行写入操作
    @Override
    protected void onNewIntent(Intent intent) {
        // TODO Auto-generated method stub
        super.onNewIntent(intent);
        if (isWrite == true
                && NfcAdapter.ACTION_TECH_DISCOVERED.equals(intent.getAction())) {
            Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
            NdefMessage ndefMessage = getNoteAsNdef();
            if (ndefMessage != null) {
                writeTag(getNoteAsNdef(), tag);
            } else {
                showToast("请输入您要写入标签的内容");
            }
        }
    }

    // 根据文本生成一个NdefRecord
    private NdefMessage getNoteAsNdef() {
        String text = mContentEditText.getText().toString();
        if (text.equals("")) {
            return null;
        } else {
            byte[] textBytes = text.getBytes();
            // image/jpeg text/plain
            NdefRecord textRecord = new NdefRecord(NdefRecord.TNF_MIME_MEDIA,
                    "image/jpeg".getBytes(), new byte[] {}, textBytes);
            return new NdefMessage(new NdefRecord[] { textRecord });
        }

    }

    // 写入tag
    boolean writeTag(NdefMessage message, Tag tag) {

        int size = message.toByteArray().length;

        try {
            Ndef ndef = Ndef.get(tag);
            if (ndef != null) {
                ndef.connect();

                if (!ndef.isWritable()) {
                    showToast("tag不允许写入");
                    return false;
                }
                if (ndef.getMaxSize() < size) {
                    showToast("文件大小超出容量");
                    return false;
                }

                ndef.writeNdefMessage(message);
                showToast("写入数据成功.");
                return true;
            } else {
                NdefFormatable format = NdefFormatable.get(tag);
                if (format != null) {
                    try {
                        format.connect();
                        format.format(message);
                        showToast("格式化tag并且写入message");
                        return true;
                    } catch (IOException e) {
                        showToast("格式化tag失败.");
                        return false;
                    }
                } else {
                    showToast("Tag不支持NDEF");
                    return false;
                }
            }
        } catch (Exception e) {
            showToast("写入数据失败");
        }

        return false;
    }

    private void showToast(String text) {
        Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
    }
}
写入标签代码展开 
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.sy.nfc.test"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <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.sy.nfc.test.ReadTag"
            android:label="@string/app_name"
            android:launchMode="singleTop" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <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" />
        </activity>
        <activity android:name="com.sy.nfc.test.WriteTag" >
            <intent-filter>
                <action android:name="android.nfc.action.TAG_DISCOVERED" />
            </intent-filter>
        </activity>
    </application>

</manifest>
配置文件展开

已经非常详细了。源码下载：

http://download.youkuaiyun.com/detail/sy_hx/6307597

可以直接运行。主要就是NFC的读写实例。有需要的下载看看

点我下载

转载于:https://www.cnblogs.com/sy171822716/p/3334925.html

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