NdefFormatable.java revision 74fe6c6b245ebe7d3b3d96962c32980d88dca4f5 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.nfc.tech;
18
19import android.nfc.ErrorCodes;
20import android.nfc.FormatException;
21import android.nfc.INfcTag;
22import android.nfc.NdefMessage;
23import android.nfc.NfcAdapter;
24import android.nfc.Tag;
25import android.nfc.TagLostException;
26import android.os.RemoteException;
27import android.util.Log;
28
29import java.io.IOException;
30
31/**
32 * Provide access to NDEF format operations on a {@link Tag}.
33 *
34 * <p>Acquire a {@link NdefFormatable} object using {@link #get}.
35 *
36 * <p>Android devices with NFC must only enumerate and implement this
37 * class for tags for which it can format to NDEF.
38 *
39 * <p>Unfortunately the procedures to convert unformated tags to NDEF formatted
40 * tags are not specified by NFC Forum, and are not generally well-known. So
41 * there is no mandatory set of tags for which all Android devices with NFC
42 * must support {@link NdefFormatable}.
43 *
44 * <p class="note"><strong>Note:</strong>
45 * Use of this class requires the {@link android.Manifest.permission#NFC}
46 * permission.
47 */
48public final class NdefFormatable extends BasicTagTechnology {
49    private static final String TAG = "NFC";
50
51    /**
52     * Get an instance of {@link NdefFormatable} for the given tag.
53     * <p>Does not cause any RF activity and does not block.
54     * <p>Returns null if {@link NdefFormatable} was not enumerated in {@link Tag#getTechList}.
55     * This indicates the tag is not NDEF formatable by this Android device.
56     *
57     * @param tag an NDEF formatable tag
58     * @return NDEF formatable object
59     */
60    public static NdefFormatable get(Tag tag) {
61        if (!tag.hasTech(TagTechnology.NDEF_FORMATABLE)) return null;
62        try {
63            return new NdefFormatable(tag);
64        } catch (RemoteException e) {
65            return null;
66        }
67    }
68
69    /**
70     * Internal constructor, to be used by NfcAdapter
71     * @hide
72     */
73    public NdefFormatable(Tag tag) throws RemoteException {
74        super(tag, TagTechnology.NDEF_FORMATABLE);
75    }
76
77    /**
78     * Format a tag as NDEF, and write a {@link NdefMessage}.
79     *
80     * <p>This is a multi-step process, an IOException is thrown
81     * if any one step fails.
82     * <p>The card is left in a read-write state after this operation.
83     *
84     * <p>This is an I/O operation and will block until complete. It must
85     * not be called from the main application thread. A blocked call will be canceled with
86     * {@link IOException} if {@link #close} is called from another thread.
87     *
88     * @param msg the NDEF message to write after formatting
89     * @throws TagLostException if the tag leaves the field
90     * @throws IOException if there is an I/O failure, or the operation is canceled
91     * @throws FormatException if the NDEF Message to write is malformed
92     */
93    public void format(NdefMessage msg) throws IOException, FormatException {
94        format(msg, false);
95    }
96
97    /**
98     * Formats a tag as NDEF, write a {@link NdefMessage}, and make read-only.
99     *
100     * <p>This is a multi-step process, an IOException is thrown
101     * if any one step fails.
102     * <p>The card is left in a read-only state if this method returns successfully.
103     *
104     * <p>This is an I/O operation and will block until complete. It must
105     * not be called from the main application thread. A blocked call will be canceled with
106     * {@link IOException} if {@link #close} is called from another thread.
107     *
108     * @param msg the NDEF message to write after formatting
109     * @throws TagLostException if the tag leaves the field
110     * @throws IOException if there is an I/O failure, or the operation is canceled
111     * @throws FormatException if the NDEF Message to write is malformed
112     */
113    public void formatReadOnly(NdefMessage msg) throws IOException, FormatException {
114        format(msg, true);
115    }
116
117    /*package*/ void format(NdefMessage firstMessage, boolean makeReadOnly) throws IOException,
118            FormatException {
119        checkConnected();
120
121        try {
122            int serviceHandle = mTag.getServiceHandle();
123            INfcTag tagService = mTag.getTagService();
124            int errorCode = tagService.formatNdef(serviceHandle, MifareClassic.KEY_DEFAULT);
125            switch (errorCode) {
126                case ErrorCodes.SUCCESS:
127                    break;
128                case ErrorCodes.ERROR_IO:
129                    throw new IOException();
130                case ErrorCodes.ERROR_INVALID_PARAM:
131                    throw new FormatException();
132                default:
133                    // Should not happen
134                    throw new IOException();
135            }
136            // Now check and see if the format worked
137            if (tagService.isNdef(serviceHandle)) {
138                errorCode = tagService.ndefWrite(serviceHandle, firstMessage);
139                switch (errorCode) {
140                    case ErrorCodes.SUCCESS:
141                        break;
142                    case ErrorCodes.ERROR_IO:
143                        throw new IOException();
144                    case ErrorCodes.ERROR_INVALID_PARAM:
145                        throw new FormatException();
146                    default:
147                        // Should not happen
148                        throw new IOException();
149                }
150            } else {
151                throw new IOException();
152            }
153            // optionally make read-only
154            if (makeReadOnly) {
155                errorCode = tagService.ndefMakeReadOnly(serviceHandle);
156                switch (errorCode) {
157                    case ErrorCodes.SUCCESS:
158                        break;
159                    case ErrorCodes.ERROR_IO:
160                        throw new IOException();
161                    case ErrorCodes.ERROR_INVALID_PARAM:
162                        throw new IOException();
163                    default:
164                        // Should not happen
165                        throw new IOException();
166                }
167            }
168        } catch (RemoteException e) {
169            Log.e(TAG, "NFC service dead", e);
170        }
171    }
172}
173