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A library jar that provides APIs for Applications written for the Google Android Platform.

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/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.nfc.tech;

import android.nfc.ErrorCodes;
import android.nfc.Tag;
import android.os.Bundle;
import android.os.RemoteException;
import android.util.Log;

import java.io.IOException;

/**
 * Provides access to NFC-A (ISO 14443-3A) properties and I/O operations on a {@link Tag}.
 *
 * 

Acquire a {@link NfcA} object using {@link #get}. *

The primary NFC-A I/O operation is {@link #transceive}. Applications must * implement their own protocol stack on top of {@link #transceive}. * *

Note: Methods that perform I/O operations * require the {@link android.Manifest.permission#NFC} permission. */ public final class NfcA extends BasicTagTechnology { private static final String TAG = "NFC"; /** @hide */ public static final String EXTRA_SAK = "sak"; /** @hide */ public static final String EXTRA_ATQA = "atqa"; private short mSak; private byte[] mAtqa; /** * Get an instance of {@link NfcA} for the given tag. *

Returns null if {@link NfcA} was not enumerated in {@link Tag#getTechList}. * This indicates the tag does not support NFC-A. *

Does not cause any RF activity and does not block. * * @param tag an NFC-A compatible tag * @return NFC-A object */ public static NfcA get(Tag tag) { if (!tag.hasTech(TagTechnology.NFC_A)) return null; try { return new NfcA(tag); } catch (RemoteException e) { return null; } } /** @hide */ public NfcA(Tag tag) throws RemoteException { super(tag, TagTechnology.NFC_A); Bundle extras = tag.getTechExtras(TagTechnology.NFC_A); mSak = extras.getShort(EXTRA_SAK); mAtqa = extras.getByteArray(EXTRA_ATQA); } /** * Return the ATQA/SENS_RES bytes from tag discovery. * *

Does not cause any RF activity and does not block. * * @return ATQA/SENS_RES bytes */ public byte[] getAtqa() { return mAtqa; } /** * Return the SAK/SEL_RES bytes from tag discovery. * *

Does not cause any RF activity and does not block. * * @return SAK bytes */ public short getSak() { return mSak; } /** * Send raw NFC-A commands to the tag and receive the response. * *

Applications must not append the EoD (CRC) to the payload, * it will be automatically calculated. *

Applications must only send commands that are complete bytes, * for example a SENS_REQ is not possible (these are used to * manage tag polling and initialization). * *

Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes * that can be sent with {@link #transceive}. * *

This is an I/O operation and will block until complete. It must * not be called from the main application thread. A blocked call will be canceled with * {@link IOException} if {@link #close} is called from another thread. * *

Requires the {@link android.Manifest.permission#NFC} permission. * * @param data bytes to send * @return bytes received in response * @throws TagLostException if the tag leaves the field * @throws IOException if there is an I/O failure, or this operation is canceled */ public byte[] transceive(byte[] data) throws IOException { return transceive(data, true); } /** * Return the maximum number of bytes that can be sent with {@link #transceive}. * @return the maximum number of bytes that can be sent with {@link #transceive}. */ public int getMaxTransceiveLength() { return getMaxTransceiveLengthInternal(); } /** * Set the {@link #transceive} timeout in milliseconds. * *

The timeout only applies to {@link #transceive} on this object, * and is reset to a default value when {@link #close} is called. * *

Setting a longer timeout may be useful when performing * transactions that require a long processing time on the tag * such as key generation. * *

Requires the {@link android.Manifest.permission#NFC} permission. * * @param timeout timeout value in milliseconds */ public void setTimeout(int timeout) { try { int err = mTag.getTagService().setTimeout(TagTechnology.NFC_A, timeout); if (err != ErrorCodes.SUCCESS) { throw new IllegalArgumentException("The supplied timeout is not valid"); } } catch (RemoteException e) { Log.e(TAG, "NFC service dead", e); } } /** * Get the current {@link #transceive} timeout in milliseconds. * *

Requires the {@link android.Manifest.permission#NFC} permission. * * @return timeout value in milliseconds */ public int getTimeout() { try { return mTag.getTagService().getTimeout(TagTechnology.NFC_A); } catch (RemoteException e) { Log.e(TAG, "NFC service dead", e); return 0; } } }





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