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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;
import java.io.IOException;
import android.os.RemoteException;
import android.util.Log;
/**
* A connection to an NDEF target on an {@link NdefTag}.
* <p>You can acquire this kind of connection with {@link NfcAdapter#createNdefTagConnection
* createNdefTagConnection()}. Use the connection to read or write {@link NdefMessage}s.
*/
public class NdefTagConnection extends RawTagConnection {
public static final int NDEF_MODE_READ_ONCE = 1;
public static final int NDEF_MODE_READ_ONLY = 2;
public static final int NDEF_MODE_WRITE_ONCE = 3;
public static final int NDEF_MODE_WRITE_MANY = 4;
public static final int NDEF_MODE_UNKNOWN = 5;
private static final String TAG = "NFC";
/**
* Internal constructor, to be used by NfcAdapter
* @hide
*/
/* package private */ NdefTagConnection(INfcAdapter service, NdefTag tag, String target) throws RemoteException {
super(service, tag);
String[] targets = tag.getNdefTargets();
int i;
// Check target validity
for (i=0; i<targets.length; i++) {
if (target.equals(targets[i])) {
break;
}
}
if (i >= targets.length) {
// Target not found
throw new IllegalArgumentException();
}
}
/**
* Internal constructor, to be used by NfcAdapter
* @hide
*/
/* package private */ NdefTagConnection(INfcAdapter service, NdefTag tag) throws RemoteException {
this(service, tag, tag.getNdefTargets()[0]);
}
/**
* Read NDEF message(s).
* This will always return the most up to date payload, and can block.
* It can be canceled with {@link RawTagConnection#close}.
* Most NDEF tags will contain just one NDEF message.
* <p>
* @throws FormatException if the tag is not NDEF formatted
* @throws IOException if the target is lost or connection closed
* @throws FormatException
*/
public NdefMessage[] readNdefMessages() throws IOException, FormatException {
//TODO(nxp): do not use getLastError(), it is racy
try {
NdefMessage[] msgArray = new NdefMessage[1];
NdefMessage msg = mTagService.read(mTag.mNativeHandle);
if (msg == null) {
int errorCode = mTagService.getLastError(mTag.mNativeHandle);
switch (errorCode) {
case ErrorCodes.ERROR_IO:
throw new IOException();
case ErrorCodes.ERROR_INVALID_PARAM:
throw new FormatException();
default:
// Should not happen
throw new IOException();
}
}
msgArray[0] = msg;
return msgArray;
} catch (RemoteException e) {
Log.e(TAG, "NFC service died");
return null;
}
}
/**
* Attempt to write an NDEF message to a tag.
* This method will block until the data is written. It can be canceled
* with {@link RawTagConnection#close}.
* Many tags are write-once, so use this method carefully.
* Specification allows for multiple NDEF messages per NDEF tag, but it is
* encourage to only write one message, this so API only takes a single
* message. Use {@link NdefRecord} to write several records to a single tag.
* For write-many tags, use {@link #makeReadOnly} after this method to attempt
* to prevent further modification. For write-once tags this is not
* neccesary.
* Requires NFC_WRITE permission.
* @throws FormatException if the tag is not suitable for NDEF messages
* @throws IOException if the target is lost or connection closed or the
* write failed
*/
public void writeNdefMessage(NdefMessage message) throws IOException, FormatException {
try {
int errorCode = mTagService.write(mTag.mNativeHandle, message);
switch (errorCode) {
case ErrorCodes.SUCCESS:
break;
case ErrorCodes.ERROR_IO:
throw new IOException();
case ErrorCodes.ERROR_INVALID_PARAM:
throw new FormatException();
default:
// Should not happen
throw new IOException();
}
} catch (RemoteException e) {
Log.e(TAG, "NFC service died");
}
}
/**
* Attempts to make the NDEF data in this tag read-only.
* This method will block until the action is complete. It can be canceled
* with {@link RawTagConnection#close}.
* Requires NFC_WRITE permission.
* @return true if the tag is now read-only
* @throws IOException if the target is lost, or connection closed
*/
public boolean makeReadOnly() throws IOException {
try {
int errorCode = mTagService.makeReadOnly(mTag.mNativeHandle);
switch (errorCode) {
case ErrorCodes.SUCCESS:
return true;
case ErrorCodes.ERROR_IO:
throw new IOException();
case ErrorCodes.ERROR_INVALID_PARAM:
return false;
default:
// Should not happen
throw new IOException();
}
} catch (RemoteException e) {
Log.e(TAG, "NFC service died");
return false;
}
}
/**
* Read/Write mode hint.
* Provides a hint if further reads or writes are likely to suceed.
* @return one of NDEF_MODE
* @throws IOException if the target is lost or connection closed
*/
public int getModeHint() throws IOException {
try {
int result = mTagService.getModeHint(mTag.mNativeHandle);
if (ErrorCodes.isError(result)) {
switch (result) {
case ErrorCodes.ERROR_IO:
throw new IOException();
default:
// Should not happen
throw new IOException();
}
}
return result;
} catch (RemoteException e) {
Log.e(TAG, "NFC service died");
return NDEF_MODE_UNKNOWN;
}
}
}
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