NFC之demo

NFC应用的demo以及相关的类的介绍如下：
TagViewer
一项activity，处理了一个新的标签，该设备只是发现广播，解析它，并将其显示在ListActivity其记录内容

NdefMessageParser 解析内NDEF消息记录类型的记录。
ParsedNdefRecord 解析NdefRecord所有类型实现的接口。
SmartPoster NFC是一个表示类型智能海报记录。
TextRecord NFC是一个文字记录表示类型。
UriRecord NFC是一个开放的记录表示类型。

FakeTagsActivity 一个activity，如果他们的发射已被标记扫描。这是有用的，如果你没有获得支持NFC设备或标签。

MockNdefMessages 这个类提供了一个未定义的NFC Ndef格式标签列表。
如果你正在开发一个应用程序使用了NFC的API，请记住，该功能只在Android 2.3（API级别9）和更高版本的平台支持。此外，在运行Android 2.3（API级别9）或更高的设备，并非所有的设备将提供NFC的支持。
demo如下：
TagViewer.java

package com.example.android.nfc;
 
import android.app.Activity;
import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.TextView;
 
import com.example.android.nfc.record.ParsedNdefRecord;
 
import java.util.List;
 
public class TagViewer extends Activity {
 
    static final String TAG = "ViewTag";
 
    static final int ACTIVITY_TIMEOUT_MS = 1 * 1000;
 
    TextView mTitle;
 
    LinearLayout mTagContent;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tag_viewer);
        mTagContent = (LinearLayout) findViewById(R.id.list);
        mTitle = (TextView) findViewById(R.id.title);
        resolveIntent(getIntent());
    }
 
    void resolveIntent(Intent intent) {
        // Parse the intent
        String action = intent.getAction();
        if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
          
            Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
            NdefMessage[] msgs;
            if (rawMsgs != null) {
                msgs = new NdefMessage[rawMsgs.length];
                for (int i = 0; i < rawMsgs.length; i++) {
                    msgs[i] = (NdefMessage) rawMsgs[i];
                }
            } else {
                // Unknown tag type
                byte[] empty = new byte[] {};
                NdefRecord record = new NdefRecord(NdefRecord.TNF_UNKNOWN, empty, empty, empty);
                NdefMessage msg = new NdefMessage(new NdefRecord[] {record});
                msgs = new NdefMessage[] {msg};
            }
            // Setup the views
            setTitle(R.string.title_scanned_tag);
            buildTagViews(msgs);
        } else {
            Log.e(TAG, "Unknown intent " + intent);
            finish();
            return;
        }
    }
 
    void buildTagViews(NdefMessage[] msgs) {
        if (msgs == null || msgs.length == 0) {
            return;
        }
        LayoutInflater inflater = LayoutInflater.from(this);
        LinearLayout content = mTagContent;
      
        content.removeAllViews();
      
        List records = NdefMessageParser.parse(msgs[0]);
        final int size = records.size();
        for (int i = 0; i < size; i++) {
            ParsedNdefRecord record = records.get(i);
            content.addView(record.getView(this, inflater, content, i));
            inflater.inflate(R.layout.tag_divider, content, true);
        }
    }
 
    @Override
    public void onNewIntent(Intent intent) {
        setIntent(intent);
        resolveIntent(intent);
    }
 
    @Override
    public void setTitle(CharSequence title) {
        mTitle.setText(title);
    }
}

 

 

NdefMessageParser.java

package com.example.android.nfc;
 
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
 
import com.example.android.nfc.record.ParsedNdefRecord;
import com.example.android.nfc.record.SmartPoster;
import com.example.android.nfc.record.TextRecord;
import com.example.android.nfc.record.UriRecord;
 
import java.util.ArrayList;
import java.util.List;

public class NdefMessageParser {
 
    // Utility class
    private NdefMessageParser() {
 
    }
 
    /** Parse an NdefMessage */
    public static List parse(NdefMessage message) {
        return getRecords(message.getRecords());
    }
 
    public static List getRecords(NdefRecord[] records) {
        List elements = new ArrayList();
        for (NdefRecord record : records) {
            if (UriRecord.isUri(record)) {
                elements.add(UriRecord.parse(record));
            } else if (TextRecord.isText(record)) {
                elements.add(TextRecord.parse(record));
            } else if (SmartPoster.isPoster(record)) {
                elements.add(SmartPoster.parse(record));
            }
        }
        return elements;
    }
}

ParsedNdefRecord.java

package com.example.android.nfc.record;
 
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
 
 
public interface ParsedNdefRecord {
 
    public View getView(Activity activity, LayoutInflater inflater, ViewGroup parent,
            int offset);
 
}

SmartPoster.java

package com.example.android.nfc.record;
 
import android.app.Activity;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
 
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
 
import com.example.android.nfc.NdefMessageParser;
import com.example.android.nfc.R;
 
import java.util.Arrays;
import java.util.NoSuchElementException;

public class SmartPoster implements ParsedNdefRecord {
 
 
    private final TextRecord mTitleRecord;
 
 
    private final UriRecord mUriRecord;
 

    private final RecommendedAction mAction;
 
 
    private final String mType;
 
    private SmartPoster(UriRecord uri, TextRecord title, RecommendedAction action, String type) {
        mUriRecord = Preconditions.checkNotNull(uri);
        mTitleRecord = title;
        mAction = Preconditions.checkNotNull(action);
        mType = type;
    }
 
    public UriRecord getUriRecord() {
        return mUriRecord;
    }
 
    public TextRecord getTitle() {
        return mTitleRecord;
    }
 
    public static SmartPoster parse(NdefRecord record) {
        Preconditions.checkArgument(record.getTnf() == NdefRecord.TNF_WELL_KNOWN);
        Preconditions.checkArgument(Arrays.equals(record.getType(), NdefRecord.RTD_SMART_POSTER));
        try {
            NdefMessage subRecords = new NdefMessage(record.getPayload());
            return parse(subRecords.getRecords());
        } catch (FormatException e) {
            throw new IllegalArgumentException(e);
        }
    }
 
    public static SmartPoster parse(NdefRecord[] recordsRaw) {
        try {
            Iterable records = NdefMessageParser.getRecords(recordsRaw);
            UriRecord uri = Iterables.getOnlyElement(Iterables.filter(records, UriRecord.class));
            TextRecord title = getFirstIfExists(records, TextRecord.class);
            RecommendedAction action = parseRecommendedAction(recordsRaw);
            String type = parseType(recordsRaw);
            return new SmartPoster(uri, title, action, type);
        } catch (NoSuchElementException e) {
            throw new IllegalArgumentException(e);
        }
    }
 
    public static boolean isPoster(NdefRecord record) {
        try {
            parse(record);
            return true;
        } catch (IllegalArgumentException e) {
            return false;
        }
    }
 
    public View getView(Activity activity, LayoutInflater inflater, ViewGroup parent, int offset) {
        if (mTitleRecord != null) {
            // Build a container to hold the title and the URI
            LinearLayout container = new LinearLayout(activity);
            container.setOrientation(LinearLayout.VERTICAL);
            container.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.WRAP_CONTENT));
            container.addView(mTitleRecord.getView(activity, inflater, container, offset));
            inflater.inflate(R.layout.tag_divider, container);
            container.addView(mUriRecord.getView(activity, inflater, container, offset));
            return container;
        } else {
            // Just a URI, return a view for it directly
            return mUriRecord.getView(activity, inflater, parent, offset);
        }
    }
 
 
    private static T getFirstIfExists(Iterable<?> elements, Class type) {
        Iterable filtered = Iterables.filter(elements, type);
        T instance = null;
        if (!Iterables.isEmpty(filtered)) {
            instance = Iterables.get(filtered, 0);
        }
        return instance;
    }
 
    private enum RecommendedAction {
        UNKNOWN((byte) -1), DO_ACTION((byte) 0), SAVE_FOR_LATER((byte) 1), OPEN_FOR_EDITING(
            (byte) 2);
 
        private static final ImmutableMap LOOKUP;
        static {
            ImmutableMap.Builder builder = ImmutableMap.builder();
            for (RecommendedAction action : RecommendedAction.values()) {
                builder.put(action.getByte(), action);
            }
            LOOKUP = builder.build();
        }
 
        private final byte mAction;
 
        private RecommendedAction(byte val) {
            this.mAction = val;
        }
 
        private byte getByte() {
            return mAction;
        }
    }
 
    private static NdefRecord getByType(byte[] type, NdefRecord[] records) {
        for (NdefRecord record : records) {
            if (Arrays.equals(type, record.getType())) {
                return record;
            }
        }
        return null;
    }
 
    private static final byte[] ACTION_RECORD_TYPE = new byte[] {'a', 'c', 't'};
 
    private static RecommendedAction parseRecommendedAction(NdefRecord[] records) {
        NdefRecord record = getByType(ACTION_RECORD_TYPE, records);
        if (record == null) {
            return RecommendedAction.UNKNOWN;
        }
        byte action = record.getPayload()[0];
        if (RecommendedAction.LOOKUP.containsKey(action)) {
            return RecommendedAction.LOOKUP.get(action);
        }
        return RecommendedAction.UNKNOWN;
    }
 
    private static final byte[] TYPE_TYPE = new byte[] {'t'};
 
    private static String parseType(NdefRecord[] records) {
        NdefRecord type = getByType(TYPE_TYPE, records);
        if (type == null) {
            return null;
        }
        return new String(type.getPayload(), Charsets.UTF_8);
    }
}