我正在开发一个Android应用程序，需要通过蓝牙连接一个设备与两个或更多的设备。连接两个设备的点对点代码是可行的，但当我尝试连接另一个设备时，会出现IOException错误提示“连接被拒绝”，因为套接字已被关闭，无法完成配对。以下是显示的错误信息：
Socket closed. Unable to complete pairing.
java.io.IOException: Connection refused
at android.bluetooth.BluetoothSocket.connectNative(Native Method)
at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:216)
at com.ablueworld.androidgridcomputingframework.BluetoothManager$ConnectAsyncTask.doInBackground(BluetoothManager.java:270)
at com.ablueworld.androidgridcomputingframework.BluetoothManager$ConnectAsyncTask.doInBackground(BluetoothManager.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:264)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
Could not connect to this device
我阅读过相关资料，发现每个连接都需要有不同的UUID，这是正确的吗？无论如何，我已经按照下面的代码编写，为每个新连接从数组中取出一个不同的UUID。
// Unique UUID for this application
private static int indexUUID = 0;
private static final UUID[] MY_UUID_SECURE = {UUID.fromString("98b97e6b-62ff-4a36-a81b-82256fd1d168"),
UUID.fromString("98b97e6b-62ff-4a36-a81b-82256fd1d169"),
UUID.fromString("98b97e6b-62ff-4a36-a81b-82256fd1d170"),
UUID.fromString("98b97e6b-62ff-4a36-a81b-82256fd1d171"),
UUID.fromString("98b97e6b-62ff-4a36-a81b-82256fd1d172")};
private static final String NAME_SECURE = "GridFrameworkSecure";
/**
* Method to connect securely to Bluetooth device using it's MAC address
* @param macAddress valid Bluetooth MAC address
*/
public boolean connectSecurelyToDevice(BluetoothAdapter btAdapter, String macAddress){
BluetoothDevice device = btAdapter.getRemoteDevice(macAddress);
ConnectAsyncTask connectTask = new ConnectAsyncTask();
BluetoothSocket deviceSocket = null;
try {
deviceSocket = connectTask.execute(device).get();
} catch (InterruptedException e) {
e.printStackTrace();
return false;
} catch (ExecutionException e) {
e.printStackTrace();
return false;
}
if(deviceSocket!=null){
if(serverBluetoothNode==null){
try {
serverBluetoothNode = new BluetoothNode(deviceSocket);
Log.i("bluetooth manager", "You are now a slave node.");
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
} else {
Log.e("bluetooth manager", "You already have a master.");
return false;
}
} else return false;
}
/**
* Method to allow this Bluetooth device to accept connection from another Bluetooth device
*/
public void allowSecureConnectionFromRemoteDevice(BluetoothAdapter btAdapter){
AcceptConnectionAsyncTask acceptTask = new AcceptConnectionAsyncTask();
acceptTask.execute(btAdapter);
}
private class ConnectAsyncTask extends AsyncTask<BluetoothDevice, Void, BluetoothSocket> {
@Override
protected BluetoothSocket doInBackground(BluetoothDevice... params) {
BluetoothDevice device = params[0];
BluetoothSocket socket = null;
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
socket = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE[indexUUID]);
} catch (IOException e) {
Log.e("Bluetooth Pairing", "create() failed", e);
}
Log.i("Bluetooth Pairing", "BEGIN ConnectThread SocketType: Secure");
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
socket.connect();
Log.i("bluetooth manager", "You have connected a slave node to this one.");
return socket;
} catch (IOException e) {
Log.e("Bluetooth Pairing", "Socket closed. Unable to complete pairing.", e);
// Close the socket
try {
socket.close();
indexUUID++;
} catch (IOException e2) {
Log.e("Bluetooth Pairing", "unable to close() socket during connection failure", e2);
}
}
return null;
}
}
private class AcceptConnectionAsyncTask extends AsyncTask<BluetoothAdapter, Void, Void> {
@Override
protected Void doInBackground(BluetoothAdapter... params) {
BluetoothServerSocket serverSocket = null;
String socketType = "Secure";
// Create a new listening server socket
try {
serverSocket = params[0].listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE[indexUUID]);
} catch (IOException e) {
Log.e("Accept Bluetooth Pairing Thread", "Socket Type: " + socketType + "listen() failed", e);
indexUUID++;
}
Log.d("Accept Bluetooth Pairing Thread", "Socket Type: " + socketType +
"BEGIN mAcceptThread" + this);
BluetoothSocket socket = null;
// Listen to the server socket if we're not connected
while (true) { //mState != STATE_CONNECTED) {
try {
// This is a blocking call and will only return on a
// successful connection or an exception
socket = serverSocket.accept();
Log.i("Slave", "server socket found");
// If a connection was accepted
if (socket != null) {
BluetoothNode node = null;
try {
node = new BluetoothNode(socket);
Log.i("connected to", node.getDeviceInformation());
slaveBluetoothNodes.add(node);
indexUUID++;
serverSocket = params[0].listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE[indexUUID]);
} catch (IOException e) {
e.printStackTrace();
indexUUID++;
serverSocket = params[0].listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE[indexUUID]);
}
}
} catch (IOException e) {
Log.e("Accept Bluetooth Pairing Thread", "Socket Type: " + socketType + "accept() failed", e);
try {
indexUUID++;
serverSocket = params[0].listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE[indexUUID]);
} catch (IOException e1) {
Log.e("Accept Bluetooth Pairing Thread", "Socket Type: " + socketType + "listen() failed", e1);
}
}
}
}
}
即便如此，当我尝试将第三个移动设备连接到已与第二个设备建立了蓝牙连接的设备时，我仍然遇到了不同的错误，如下所示。
Socket closed. Unable to complete pairing.
java.io.IOException: Service discovery failed
at android.bluetooth.BluetoothSocket$SdpHelper.doSdp(BluetoothSocket.java:406)
at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:217)
at com.ablueworld.androidgridcomputingframework.BluetoothManager$ConnectAsyncTask.doInBackground(BluetoothManager.java:270)
at com.ablueworld.androidgridcomputingframework.BluetoothManager$ConnectAsyncTask.doInBackground(BluetoothManager.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:185)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
at java.lang.Thread.run(Thread.java:1019)
Could not connect to this device
有人能帮忙弄清楚这个问题吗？谢谢。