1 files changed, 149 insertions, 0 deletions
diff --git a/samples/browseable/CardReader/src/com.example.android.cardreader/LoyaltyCardReader.java b/samples/browseable/CardReader/src/com.example.android.cardreader/LoyaltyCardReader.java
new file mode 100644
index 000000000..c29bdfdea
--- /dev/null
+++ b/samples/browseable/CardReader/src/com.example.android.cardreader/LoyaltyCardReader.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2013 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 com.example.android.cardreader;
+
+import android.nfc.NfcAdapter;
+import android.nfc.Tag;
+import android.nfc.tech.IsoDep;
+
+import com.example.android.common.logger.Log;
+
+import java.io.IOException;
+import java.lang.ref.WeakReference;
+import java.util.Arrays;
+
+/**
+ * Callback class, invoked when an NFC card is scanned while the device is running in reader mode.
+ *
+ * Reader mode can be invoked by calling NfcAdapter
+ */
+public class LoyaltyCardReader implements NfcAdapter.ReaderCallback {
+    private static final String TAG = "LoyaltyCardReader";
+    // AID for our loyalty card service.
+    private static final String SAMPLE_LOYALTY_CARD_AID = "F222222222";
+    // ISO-DEP command HEADER for selecting an AID.
+    // Format: [Class | Instruction | Parameter 1 | Parameter 2]
+    private static final String SELECT_APDU_HEADER = "00A40400";
+    // "OK" status word sent in response to SELECT AID command (0x9000)
+    private static final byte[] SELECT_OK_SW = {(byte) 0x90, (byte) 0x00};
+
+    // Weak reference to prevent retain loop. mAccountCallback is responsible for exiting
+    // foreground mode before it becomes invalid (e.g. during onPause() or onStop()).
+    private WeakReference<AccountCallback> mAccountCallback;
+
+    public interface AccountCallback {
+        public void onAccountReceived(String account);
+    }
+
+    public LoyaltyCardReader(AccountCallback accountCallback) {
+        mAccountCallback = new WeakReference<AccountCallback>(accountCallback);
+    }
+
+    /**
+     * Callback when a new tag is discovered by the system.
+     *
+     * <p>Communication with the card should take place here.
+     *
+     * @param tag Discovered tag
+     */
+    @Override
+    public void onTagDiscovered(Tag tag) {
+        Log.i(TAG, "New tag discovered");
+        // Android's Host-based Card Emulation (HCE) feature implements the ISO-DEP (ISO 14443-4)
+        // protocol.
+        //
+        // In order to communicate with a device using HCE, the discovered tag should be processed
+        // using the IsoDep class.
+        IsoDep isoDep = IsoDep.get(tag);
+        if (isoDep != null) {
+            try {
+                // Connect to the remote NFC device
+                isoDep.connect();
+                // Build SELECT AID command for our loyalty card service.
+                // This command tells the remote device which service we wish to communicate with.
+                Log.i(TAG, "Requesting remote AID: " + SAMPLE_LOYALTY_CARD_AID);
+                byte[] command = BuildSelectApdu(SAMPLE_LOYALTY_CARD_AID);
+                // Send command to remote device
+                Log.i(TAG, "Sending: " + ByteArrayToHexString(command));
+                byte[] result = isoDep.transceive(command);
+                // If AID is successfully selected, 0x9000 is returned as the status word (last 2
+                // bytes of the result) by convention. Everything before the status word is
+                // optional payload, which is used here to hold the account number.
+                int resultLength = result.length;
+                byte[] statusWord = {result[resultLength-2], result[resultLength-1]};
+                byte[] payload = Arrays.copyOf(result, resultLength-2);
+                if (Arrays.equals(SELECT_OK_SW, statusWord)) {
+                    // The remote NFC device will immediately respond with its stored account number
+                    String accountNumber = new String(payload, "UTF-8");
+                    Log.i(TAG, "Received: " + accountNumber);
+                    // Inform CardReaderFragment of received account number
+                    mAccountCallback.get().onAccountReceived(accountNumber);
+                }
+            } catch (IOException e) {
+                Log.e(TAG, "Error communicating with card: " + e.toString());
+            }
+        }
+    }
+
+    /**
+     * Build APDU for SELECT AID command. This command indicates which service a reader is
+     * interested in communicating with. See ISO 7816-4.
+     *
+     * @param aid Application ID (AID) to select
+     * @return APDU for SELECT AID command
+     */
+    public static byte[] BuildSelectApdu(String aid) {
+        // Format: [CLASS | INSTRUCTION | PARAMETER 1 | PARAMETER 2 | LENGTH | DATA]
+        return HexStringToByteArray(SELECT_APDU_HEADER + String.format("%02X", aid.length() / 2) + aid);
+    }
+
+    /**
+     * Utility class to convert a byte array to a hexadecimal string.
+     *
+     * @param bytes Bytes to convert
+     * @return String, containing hexadecimal representation.
+     */
+    public static String ByteArrayToHexString(byte[] bytes) {
+        final char[] hexArray = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
+        char[] hexChars = new char[bytes.length * 2];
+        int v;
+        for ( int j = 0; j < bytes.length; j++ ) {
+            v = bytes[j] & 0xFF;
+            hexChars[j * 2] = hexArray[v >>> 4];
+            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
+        }
+        return new String(hexChars);
+    }
+
+    /**
+     * Utility class to convert a hexadecimal string to a byte string.
+     *
+     * <p>Behavior with input strings containing non-hexadecimal characters is undefined.
+     *
+     * @param s String containing hexadecimal characters to convert
+     * @return Byte array generated from input
+     */
+    public static byte[] HexStringToByteArray(String s) {
+        int len = s.length();
+        byte[] data = new byte[len / 2];
+        for (int i = 0; i < len; i += 2) {
+            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+                    + Character.digit(s.charAt(i+1), 16));
+        }
+        return data;
+    }
+
+}