android.nfc.tech.NfcA Maven / Gradle / Ivy
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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;
}
}
}