/* * 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; import android.os.Parcel; import android.os.Parcelable; /** * Represents an NDEF (NFC Data Exchange Format) data message that contains one or more {@link * NdefRecord}s. *

An NDEF message includes "records" that can contain different sets of data, such as * MIME-type media, a URI, or one of the supported RTD types (see {@link NdefRecord}). An NDEF * message always contains zero or more NDEF records.

*

This is an immutable data class. */ public final class NdefMessage implements Parcelable { private static final byte FLAG_MB = (byte) 0x80; private static final byte FLAG_ME = (byte) 0x40; private final NdefRecord[] mRecords; /** * Create an NDEF message from raw bytes. *

* Validation is performed to make sure the Record format headers are valid, * and the ID + TYPE + PAYLOAD fields are of the correct size. * @throws FormatException */ public NdefMessage(byte[] data) throws FormatException { mRecords = null; // stop compiler complaints about final field if (parseNdefMessage(data) == -1) { throw new FormatException("Error while parsing NDEF message"); } } /** * Create an NDEF message from NDEF records. */ public NdefMessage(NdefRecord[] records) { mRecords = new NdefRecord[records.length]; System.arraycopy(records, 0, mRecords, 0, records.length); } /** * Get the NDEF records inside this NDEF message. * * @return array of zero or more NDEF records. */ public NdefRecord[] getRecords() { return mRecords.clone(); } /** * Returns a byte array representation of this entire NDEF message. */ public byte[] toByteArray() { //TODO: allocate the byte array once, copy each record once //TODO: process MB and ME flags outside loop if ((mRecords == null) || (mRecords.length == 0)) return new byte[0]; byte[] msg = {}; for (int i = 0; i < mRecords.length; i++) { byte[] record = mRecords[i].toByteArray(); byte[] tmp = new byte[msg.length + record.length]; /* Make sure the Message Begin flag is set only for the first record */ if (i == 0) { record[0] |= FLAG_MB; } else { record[0] &= ~FLAG_MB; } /* Make sure the Message End flag is set only for the last record */ if (i == (mRecords.length - 1)) { record[0] |= FLAG_ME; } else { record[0] &= ~FLAG_ME; } System.arraycopy(msg, 0, tmp, 0, msg.length); System.arraycopy(record, 0, tmp, msg.length, record.length); msg = tmp; } return msg; } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeInt(mRecords.length); dest.writeTypedArray(mRecords, flags); } public static final Parcelable.Creator CREATOR = new Parcelable.Creator() { @Override public NdefMessage createFromParcel(Parcel in) { int recordsLength = in.readInt(); NdefRecord[] records = new NdefRecord[recordsLength]; in.readTypedArray(records, NdefRecord.CREATOR); return new NdefMessage(records); } @Override public NdefMessage[] newArray(int size) { return new NdefMessage[size]; } }; private native int parseNdefMessage(byte[] data); }