NFC 読み取りサンプル

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【Android】 NFC を試しました

で使ってる NFC 読み取りサンプルの Gist

書籍『NFC Hacks』（株式会社ブリリアントサービス著, オライリージャパン発行）の Hack #32 を参考にして作成

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvInfo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.nfcreaderexample">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTask">
            <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.NDEF_DISCOVERED" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="image/jpeg" />
            </intent-filter>

            <intent-filter>
                <action android:name="android.nfc.action.TECH_DISCOVERED" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech_filter" />

            <intent-filter>
                <action android:name="android.nfc.action.TAG_DISCOVERED" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
-->
        </activity>
    </application>

</manifest>

MainActivity.java

package com.example.nfcreaderexample;

import androidx.appcompat.app.AppCompatActivity;

import android.app.PendingIntent;
import android.content.Intent;
import android.content.IntentFilter;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.TagTechnology;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.widget.TextView;

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

/**
 * 書籍 NFC Hacks の Hack #32 を参考に作成した、
 * NFC読み込みアプリのサンプル実装
 */
public class MainActivity extends AppCompatActivity {

    private final String TAG = MainActivity.class.getSimpleName();

    private NfcAdapter mNfcAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.d(TAG, "onCreate");

        mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
        Intent intent = this.getIntent();
        analyze(intent);
    }

    @Override
    protected void onPause() {
        super.onPause();
        mNfcAdapter.disableForegroundDispatch(this);
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        Log.d(TAG, "onNewIntent");
        analyze(intent);
    }

    private void analyze(Intent intent) {
        if (intent == null) {
            Log.d(TAG, "analyze: no intent");
            return;
        }

        if (intent.getAction().equals(NfcAdapter.ACTION_NDEF_DISCOVERED)) {
            StringBuilder sb = new StringBuilder();
            sb.append("ACTION_NDEF_DISCOVERED\n");
            getNdefInfo(intent, sb);
            ((TextView) findViewById(R.id.tvInfo)).setText(new String(sb));
        } else if (intent.getAction().equals(NfcAdapter.ACTION_TECH_DISCOVERED)) {
            StringBuilder sb = new StringBuilder();
            sb.append("ACTION_TECH_DISCOVERED\n");
            getTechInfo(intent, sb);
            ((TextView) findViewById(R.id.tvInfo)).setText(new String(sb));
        } else if (intent.getAction().equals(NfcAdapter.ACTION_TAG_DISCOVERED)) {
            StringBuilder sb = new StringBuilder();
            sb.append("ACTION_TAG_DISCOVERED\n");
            getTechInfo(intent, sb);
            ((TextView) findViewById(R.id.tvInfo)).setText(new String(sb));
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()), 0);
        IntentFilter ndefFilter = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
        IntentFilter techFilter = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
        IntentFilter tagFilter = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);

        // NDEF_DISCOVERED, text/plain に対応
        try {
            ndefFilter.addDataType("text/plain");
        } catch (IntentFilter.MalformedMimeTypeException e) {
            e.printStackTrace();
        }

        IntentFilter[] intentFilters = new IntentFilter[] {ndefFilter, techFilter, tagFilter};

        // TECH_DISCOVERED, NDEF を指定
        String tech = Ndef.class.getName();
        String techlist[] = new String[]{tech};           // and 条件
        String techLists[][] = new String[][] {techlist}; // or 条件

        // すべてを受け付ける
        //mNfcAdapter.enableForegroundDispatch(this, pendingIntent, null, null);

        // ACTION_TECH_DISCOVERED 用に tech list を指定
        mNfcAdapter.enableForegroundDispatch(this, pendingIntent, intentFilters, techLists);
    }

    private void getNdefInfo(Intent intent, StringBuilder sb) {
        getTagInfo(intent, sb);

        NdefMessage[] msgs = null;
        Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
        if (rawMsgs != null) {
            msgs = new NdefMessage[rawMsgs.length];
            for (int i = 0; i < rawMsgs.length; i++) {
                msgs[i] = (NdefMessage) rawMsgs[i];
            }
        }

        if (msgs != null) {
            sb.append("NDEF INFO\n");

            for (int i = 0; i < msgs.length; i++) {
                sb.append("message #:");
                sb.append(i);
                sb.append("\n");

                NdefRecord[] records = msgs[i].getRecords();
                for (int j = 0; j < records.length; j++) {
                    sb.append("record #:");
                    sb.append(j);
                    sb.append("\n");
                    parseNdefRecord(records[j], sb);
                }
                sb.append("\n");
            }
        }
    }
    private void parseNdefRecord(NdefRecord record, StringBuilder sb) {
        sb.append(" record id:");
        sb.append(new String(record.getId())); // byte配列 -> String
        sb.append("\n");
        sb.append(" tnf:");
        switch (record.getTnf()) {
            case NdefRecord.TNF_EMPTY:
                sb.append("TNF_EMPTY");
                break;
            case NdefRecord.TNF_WELL_KNOWN:
                sb.append("TNF_WELL_KNOWN");
                break;
            case NdefRecord.TNF_MIME_MEDIA:
                sb.append("TNF_MIME_MEDIA");
                break;
            case NdefRecord.TNF_ABSOLUTE_URI:
                sb.append("TNF_ABSOLUTE_URI");
                break;
            case NdefRecord.TNF_EXTERNAL_TYPE:
                sb.append("TNF_EXTERNAL_TYPE");
                break;
            case NdefRecord.TNF_UNKNOWN:
                sb.append("TNF_UNKOWN");
                break;
            case NdefRecord.TNF_UNCHANGED:
                sb.append("TNF_UNCHANGED");
                break;
        }
        sb.append("\n");
        sb.append(" type:");
        sb.append(new String(record.getType()));
        sb.append("\n");
        sb.append(" payload:");
        sb.append(new String(record.getPayload()));
        sb.append("\n");
    }

    private void getTechInfo(Intent intent, StringBuilder sb) {
        getTagInfo(intent, sb);

        Tag tag = null;
        tag = (Tag) intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        if (tag != null) {
            List<String> techList = Arrays.asList(tag.getTechList());

            if (techList.contains(Ndef.class.getName())) {
                sb.append("TECH NDEF INFO\n");

                Ndef ndef = Ndef.get(tag);

                sb.append(" tag type:");
                sb.append(ndef.getType());
                sb.append("\n");
                sb.append(" max size:");
                sb.append(ndef.getMaxSize());
                sb.append("\n");

                try {
                    NdefMessage msg = null;

                    ndef.connect();
                    msg = ndef.getNdefMessage();

                    if (msg != null) {
                        NdefRecord records[] = msg.getRecords();
                        for (int j = 0; j < records.length; j++) {
                            sb.append("record #:");
                            sb.append(j);
                            parseNdefRecord(records[j], sb);
                        }
                        sb.append("\n");
                    } else {
                        sb.append("msg is null\n");
                    }
                } catch (FormatException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        ndef.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    private void getTagInfo(Intent intent, StringBuilder sb) {
        sb.append("TAG INFO\n");

        Tag tag = null;
        tag = (Tag) intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        if (tag != null) {
            sb.append(" id:");
            setIdFromBytes(tag.getId(), sb);
            sb.append("\n");

            String[] techList = tag.getTechList();
            if (techList != null) {
                sb.append("tech list:\n");
                for (int i = 0; i < techList.length; i++) {
                    sb.append(techList[i]);
                    sb.append("\n");
                }
            }
        }
    }

    private void setIdFromBytes(byte[] bytes, StringBuilder sb) {
        for (byte b: bytes) {
            sb.append(String.format("%02x", b));
        }
    }
}

nfc_tech_filter.xml

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">

    <tech-list>
        <!--
        <tech>android.nfc.IsoDep</tech>
        <tech>android.nfc.tech.MifareClassic</tech>
        <tech>android.nfc.tech.MifareUltralight</tech>
        -->
        <tech>android.nfc.tech.Ndef</tech>
        <!--
        <tech>android.nfc.tech.NdefFormatable</tech>
        <tech>android.nfc.tech.NfcA</tech>
        <tech>android.nfc.tech.NfcB</tech>
        <tech>android.nfc.tech.NfcBarcode</tech>
        <tech>android.nfc.tech.NfcF</tech>
        <tech>android.nfc.tech.NfcV</tech>
        -->
    </tech-list>

</resources>