I'm new in developing with ACR or NFC Reader, especially for Android. And recently I need to use an ACR35 and I've got the SDK and the example from this acs official website. And It works just fine as an example. And now I need to create an activity that will always be ready to check whether nfc card is tapped. But the problem is I don't know how to detect when the nfc card is tapped and I don't know what to do next, and I can't find the way out from the example as it detects nfc card when I touch the 'transmit' button, it doesn't do it automatically. Please give me with example code. Thanks for your answer.
可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):
问题:
回答1:
A bit late, but it might help someone. I have found following project on the git hub. It shows how to read tag id from the acr35 here .
I have been using acr35 for some time to read the tag id. From my experience is a buggy device on Android. I tested around 10 devices and it worked only on 3...
I read from it every second. It returns results from the last card even though it is not present there anymore. Therefore; I have to reset it twice per every successful read and it takes around 6 seconds to get the device in reading state again... Also be very careful with multithreading.
My implementation based on mentioned project - added simple locking to stop querying the card after successfull reading + full device reset, filternig same uuid which was read in very short time after it was read previously:
ACR3x class
import com.acs.audiojack.AudioJackReader;
import android.media.AudioManager;
import sk.tido.util.ByteHex;
import java.util.Date;
/**
* This class allows control of the ACR35 reader sleep state and PICC commands
*/
public class Acr3x {
private Acr3xTransmitter transmitter;
private AudioManager mAudioManager;
private AudioJackReader mReader;
private boolean firstReset = true; /** Is this the first reset of the reader? */
/** APDU command for reading a card's UID */
private final byte[] apdu = { (byte) 0xFF, (byte) 0xCA, (byte) 0x00, (byte) 0x00, (byte) 0x00 };
/** Timeout for APDU response (in <b>seconds</b>) */
private final int timeout = 1;
private int acr3xCardType = AudioJackReader.PICC_CARD_TYPE_ISO14443_TYPE_A
| AudioJackReader.PICC_CARD_TYPE_ISO14443_TYPE_B
| AudioJackReader.PICC_CARD_TYPE_FELICA_212KBPS
| AudioJackReader.PICC_CARD_TYPE_FELICA_424KBPS
| AudioJackReader.PICC_CARD_TYPE_AUTO_RATS;
private int acr3xStartAudioLevel = 0;
private Object locking = new Object();
private String lastUuid = "";
private Date lastUuidDate = new Date();
public Acr3x(AudioManager mAudioManager){
this.mAudioManager = mAudioManager;
}
public void start(final Acr3xNotifListener listener){
Runnable r = new Runnable(){
@Override
public void run() {
if(mReader == null){
mReader = new AudioJackReader(mAudioManager);
}
System.out.println("ACR35 reader start");
acr3xStartAudioLevel = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
System.out.println("acr3x start audio stream level: " + acr3xStartAudioLevel);
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC,
mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC), 0);
System.out.println("acr3x set audio stream level: " + mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC));
mReader.start();
mReader.setSleepTimeout(30);
mReader.setOnFirmwareVersionAvailableListener(new AudioJackReader.OnFirmwareVersionAvailableListener() {
@Override
public void onFirmwareVersionAvailable(AudioJackReader reader,
String firmwareVersion) {
System.out.println("acr3x firmware version: " + firmwareVersion);
if(listener != null){
listener.onFirmwareVersionAvailable(firmwareVersion);
}
Acr3x.this.read(listener);
}
});
mReader.reset(new AudioJackReader.OnResetCompleteListener(){
@Override
public void onResetComplete(AudioJackReader arg0) {
mReader.getFirmwareVersion();
}
});
}
};
Thread t = new Thread(r, "Acr3xInitThread");
t.start();
}
/**
* Sets the ACR35 reader to continuously poll for the presence of a card. If a card is found,
* the UID will be returned to the Apache Cordova application
*
* @param callbackContext: the callback context provided by Cordova
* @param cardType: the integer representing card type
*/
public void read(final Acr3xNotifListener callbackContext){
System.out.println("acr3x setting up for reading...");
firstReset = true;
/* Set the PICC response APDU callback */
mReader.setOnPiccResponseApduAvailableListener
(new AudioJackReader.OnPiccResponseApduAvailableListener() {
@Override
public void onPiccResponseApduAvailable(AudioJackReader reader,
byte[] responseApdu) {
/* Update the connection status of the transmitter */
transmitter.updateStatus(true);
/* Print out the UID */
String uuid = ByteHex.bytesToHex(responseApdu);
if(uuid.equalsIgnoreCase("0x9000")){
return;
}
if(uuid.endsWith("9000")){
uuid = uuid.substring(0, uuid.length() - 4);
}
if(uuid.equals(lastUuid)){ // na odfiltrovanie opakujucich sa uuid z citacky z predchadzajuceho citania
if(new Date().getTime() - lastUuidDate.getTime() < 3000){
return;
}
}
lastUuid = uuid;
lastUuidDate = new Date();
synchronized(locking){
System.out.println("acr3x uuid: " + uuid);
if(callbackContext != null){
callbackContext.onUUIDAavailable(uuid);
}
System.out.println("acr3x restarting reader");
transmitter.kill();
try {
locking.wait(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
read(callbackContext);
}
});
/* Set the reset complete callback */
mReader.setOnResetCompleteListener(new AudioJackReader.OnResetCompleteListener() {
@Override
public void onResetComplete(AudioJackReader reader) {
System.out.println("acr3x reset complete");
/* If this is the first reset, the ACR35 reader must be turned off and back on again
to work reliably... */
Thread t = null;
if(firstReset){ //firstReset
t = new Thread(new Runnable() {
public void run() {
try{
/* Set the reader asleep */
mReader.sleep();
/* Wait one second */
Thread.sleep(500);
/* Reset the reader */
mReader.reset();
firstReset = false;
} catch (InterruptedException e) {
e.printStackTrace();
// TODO: add exception handling
}
}
});
} else {
/* Create a new transmitter for the UID read command */
transmitter = new Acr3xTransmitter(mReader, mAudioManager, timeout,
apdu, acr3xCardType, locking);
t = new Thread(transmitter);
}
t.start();
}
});
mReader.start();
mReader.reset();
System.out.println("acr3x setup complete");
}
public void stop(){
if(transmitter != null){
transmitter.kill();
}
System.out.println("acr3x restoring audio level: " + acr3xStartAudioLevel);
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC,acr3xStartAudioLevel, 0);
System.out.println("acr3x set audio stream level: " + mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC));
if(mReader != null){
mReader.stop();
}
}
}
Transmitter class
import com.acs.audiojack.AudioJackReader;
import android.media.AudioManager;
/**
* This class sets up an independent thread for card polling, and is linked to the
* <code>setOnPiccResponseApduAvailableListener</code> callback function
*/
public class Acr3xTransmitter implements Runnable {
private AudioJackReader mReader;
private AudioManager mAudioManager;
//private CallbackContext mContext;
private boolean killMe = false; /** Stop the polling thread? */
private int itersWithoutResponse = 0; /** The number of iterations that have passed with no
response from the reader */
private boolean readerConnected = true; /** Is the reader currently connected? */
private int cardType;
private int timeout;
private byte[] apdu;
private Object locking;
/**
* @param mReader: AudioJack reader service
* @param mAudioManager: system audio service
* @param mContext: context for plugin results
* @param timeout: time in <b>seconds</b> to wait for commands to complete
* @param apdu: byte array containing the command to be sent
* @param cardType: the integer representing card type
*/
public Acr3xTransmitter(AudioJackReader mReader, AudioManager mAudioManager,
int timeout, byte[] apdu, int cardType, Object locking){
this.mReader = mReader;
this.mAudioManager = mAudioManager;
this.timeout = timeout;
this.apdu = apdu;
this.cardType = cardType;
this.locking = locking;
}
/**
* Stops the polling thread
*/
public void kill(){
killMe = true;
}
/**
* Updates the connection status of the reader (links to APDU response callback)
*/
public void updateStatus(boolean status){
readerConnected = status;
}
/**
* Sends the APDU command for reading a card UID every second
*/
@Override
public void run() {
try {
/* Wait one second for stability */
Thread.sleep(1000);
while (!killMe) {
synchronized(locking){
if(killMe){
continue;
}
/* If the reader is not connected, increment no. of iterations without response */
if(!readerConnected){
itersWithoutResponse++;
}
/* Else, reset the number of iterations without a response */
else{
itersWithoutResponse = 0;
}
/* Reset the connection state */
readerConnected = false;
if(itersWithoutResponse == 4) {
/* Communicate to the Cordova application that the reader is disconnected */
System.out.println("acr3x disconnected");
/* Kill this thread */
kill();
} else if(!mAudioManager.isWiredHeadsetOn()) {
System.out.println("acr3x not connected");
/* Kill this thread */
kill();
} else{
System.out.println("acr3x reading...");
/* Power on the PICC */
mReader.piccPowerOn(timeout, cardType);
/* Transmit the APDU */
mReader.piccTransmit(timeout, apdu);
}
}
/* Repeat every second */
Thread.sleep(1000);
}
/* Power off the PICC */
mReader.piccPowerOff();
/* Set the reader asleep */
mReader.sleep();
/* Stop the reader service */
mReader.stop();
synchronized(locking){
locking.notifyAll();
}
} catch (InterruptedException e) {
e.printStackTrace();
// TODO: add exception handling
}
}
}
listener interface:
public interface Acr3xNotifListener {
public void onUUIDAavailable(String uuid);
public void onFirmwareVersionAvailable(String firmwareVersion);
}
回答2:
First you call the Reset command to activate the device. As the device will fall asleep (after 4 seconds by default)* the trick is to keeping it alive.
You can achieve that by relaunching a new PowerOn command every time the previous PowerOn timedOut. Something like that
void powerOn () {
if (!mReader.piccPowerOn(mPiccTimeout, mPiccCardType)) {
powerOn();
} else {
askNfcForItsId();
}
Don't forget to call powerOn after you read the nfc otherwise it will fall asleep after the 1st nfc card.
*the reset timeout can be set between 4 and 20 seconds
![Prime Path[POJ3126] [SPFA/BFS]](https://oscimg.oschina.net/oscnet/e1200f32e838bf1d387d671dc8e6894c37d.jpg "Prime Path[POJ3126] [SPFA/BFS]")
