Android 连接到外部热敏打印机时断开蓝牙连接

我正在创建一个将收据打印到蓝牙外部打印机的应用程序！我能够成功地配置他们的SDK，并能够打印到外部设备！我实现的方法是，当我单击我的打印按钮时，它会搜索配对设备，当选择打印机时，它会将mac id保存到prefrence并调用打印功能！下一次当我点击打印按钮时，它不会像首选项一样进行搜索，它有设备的mac Id，并要求打印

我面临的问题是，当我第一次单击“打印”按钮时，它会工作并打印，而当我再次按下设备连接时，它会丢失，无法连接弹出的toast，并且不会打印！当我再次连接它打印成功。这种事一直在发生！如果我让我的设备闲置一段时间，那么打印也会发生！蓝牙关闭和打开时也会打印

我的蓝牙服务：

public class BluetoothService {
    // Debugging
    private static final String TAG = "BluetoothService";
    private static final boolean DEBUG = true;

    // Name for the SDP record when creating server socket
    private static final String NAME = "ZJPrinter";
    //UUID must be this
    // Unique UUID for this application
    private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    // Member fields
    private BluetoothAdapter mAdapter;
    private Handler mHandler;
    private AcceptThread mAcceptThread;
    private ConnectThread mConnectThread;
    private ConnectedThread mConnectedThread;
    private int mState;

    // Constants that indicate the current connection state
    public static final int STATE_NONE = 0;       // we're doing nothing
    public static final int STATE_LISTEN = 1;     // now listening for incoming connections
    public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
    public static final int STATE_CONNECTED = 3;  // now connected to a remote device

    public static String ErrorMessage = "No_Error_Message";
    /**
     * Constructor. Prepares a new BTPrinter session.
     * @param context  The UI Activity Context
     * @param handler  A Handler to send messages back to the UI Activity
     */
    public BluetoothService(Context context, Handler handler) {
        mAdapter = BluetoothAdapter.getDefaultAdapter();
        mState = STATE_NONE;
        mHandler = handler;
    }


    /**
     * Set the current state of the connection
     * @param state  An integer defining the current connection state
     */
    private synchronized void setState(int state) {
        if (DEBUG) Log.d(TAG, "setState() " + mState + " -> " + state);
        mState = state;

        // Give the new state to the Handler so the UI Activity can update
        mHandler.obtainMessage(PrintBluetooth.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
    }

    /**
     * Return the current connection state. */
    public synchronized int getState() {
        return mState;
    }

    /**
     * Start the service. Specifically start AcceptThread to begin a
     * session in listening (server) mode. Called by the Activity onResume() */
    public synchronized void start() {
        if (DEBUG) Log.d(TAG, "start");

        // Cancel any thread attempting to make a connection
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Start the thread to listen on a BluetoothServerSocket
        if (mAcceptThread == null) {
            mAcceptThread = new AcceptThread();
            mAcceptThread.start();
        }
        setState(STATE_LISTEN);
    }

    /**
     * Start the ConnectThread to initiate a connection to a remote device.
     * @param device  The BluetoothDevice to connect
     */
    public synchronized void connect(BluetoothDevice device) {
        if (DEBUG) Log.d(TAG, "connect to: " + device);

        // Cancel any thread attempting to make a connection
        if (mState == STATE_CONNECTING) {
            if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
        }

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Start the thread to connect with the given device
        mConnectThread = new ConnectThread(device);
        mConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /**
     * Start the ConnectedThread to begin managing a Bluetooth connection
     * @param socket  The BluetoothSocket on which the connection was made
     * @param device  The BluetoothDevice that has been connected
     */
    public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) {
        if (DEBUG) Log.d(TAG, "connected");

        // Cancel the thread that completed the connection
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}

        // Cancel any thread currently running a connection
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}

        // Cancel the accept thread because we only want to connect to one device
        if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}

        // Start the thread to manage the connection and perform transmissions
        mConnectedThread = new ConnectedThread(socket);
        mConnectedThread.start();

        // Send the name of the connected device back to the UI Activity
        Message msg = mHandler.obtainMessage(PrintBluetooth.MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(PrintBluetooth.DEVICE_NAME, device.getName());
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        setState(STATE_CONNECTED);
    }

    /**
     * Stop all threads
     */
    public synchronized void stop() {
        if (DEBUG) Log.d(TAG, "stop");
        setState(STATE_NONE);
        if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
        if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
        if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}
    }

    /**
     * Write to the ConnectedThread in an unsynchronized manner
     * @param out The bytes to write
     * @see ConnectedThread#write(byte[])
     */
    public void write(byte[] out) {
        // Create temporary object
        ConnectedThread r;
        // Synchronize a copy of the ConnectedThread
        synchronized (this) {
            if (mState != STATE_CONNECTED) return;
            r = mConnectedThread;
        }
        r.write(out);
    }

    /**
     * Indicate that the connection attempt failed and notify the UI Activity.
     */
    private void connectionFailed() {
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = mHandler.obtainMessage(PrintBluetooth.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(PrintBluetooth.TOAST, "Unable to connect device");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    /**
     * Indicate that the connection was lost and notify the UI Activity.
     */
    private void connectionLost() {
        //setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = mHandler.obtainMessage(PrintBluetooth.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(PrintBluetooth.TOAST, "Device connection was lost!");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    /**
     * This thread runs while listening for incoming connections. It behaves
     * like a server-side client. It runs until a connection is accepted
     * (or until cancelled).
     */
    private class AcceptThread extends Thread {
        // The local server socket
        private final BluetoothServerSocket mmServerSocket;

        public AcceptThread() {
            BluetoothServerSocket tmp = null;

            // Create a new listening server socket
            try {
                tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
            } catch (IOException e) {
                Log.e(TAG, "listen() failed", e);
            }
            mmServerSocket = tmp;
        }

        @Override
        public void run() {
            if (DEBUG) Log.d(TAG, "BEGIN mAcceptThread" + this);
            setName("AcceptThread");
            BluetoothSocket socket = null;

            // Listen to the server socket if we're not connected
            while (mState != STATE_CONNECTED) {
                try {
                    // This is a blocking call and will only return on a
                    // successful connection or an exception
                    socket = mmServerSocket.accept();
                } catch (IOException e) {
                    Log.e(TAG, "accept() failed", e);
                    break;
                }

                // If a connection was accepted
                if (socket != null) {
                    synchronized (BluetoothService.this) {
                        switch (mState) {
                        case STATE_LISTEN:
                        case STATE_CONNECTING:
                            // Situation normal. Start the connected thread.
                            connected(socket, socket.getRemoteDevice());
                            break;
                        case STATE_NONE:
                        case STATE_CONNECTED:
                            // Either not ready or already connected. Terminate new socket.
                            try {
                                socket.close();
                            } catch (IOException e) {
                                Log.e(TAG, "Could not close unwanted socket", e);
                            }
                            break;
                        }
                    }
                }
            }
            if (DEBUG) Log.i(TAG, "END mAcceptThread");
        }

        public void cancel() {
            if (DEBUG) Log.d(TAG, "cancel " + this);
            try {
                mmServerSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of server failed", e);
            }
        }
    }


    /**
     * This thread runs while attempting to make an outgoing connection
     * with a device. It runs straight through; the connection either
     * succeeds or fails.
     */
    private class ConnectThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final BluetoothDevice mmDevice;

        public ConnectThread(BluetoothDevice device) {
            mmDevice = device;
            BluetoothSocket tmp = null;

            // Get a BluetoothSocket for a connection with the
            // given BluetoothDevice
            try {
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e) {
                Log.e(TAG, "create() failed", e);
            }
            mmSocket = tmp;
        }

        @Override
        public void run() {
            Log.i(TAG, "BEGIN mConnectThread");
            setName("ConnectThread");

            // Always cancel discovery because it will slow down a connection
            mAdapter.cancelDiscovery();

            // Make a connection to the BluetoothSocket
            try {
                // This is a blocking call and will only return on a
                // successful connection or an exception
                mmSocket.connect();
            } catch (IOException e) {
                Log.e("ERRROR :::::","INSIDE CATCH RUN");
                connectionFailed();
                // Close the socket
                try {
                    mmSocket.close();
                } catch (IOException e2) {
                    Log.e(TAG, "unable to close() socket during connection failure", e2);
                }
                // Start the service over to restart listening mode
                BluetoothService.this.start();
                return;
            }

            // Reset the ConnectThread because we're done
            synchronized (BluetoothService.this) {
                mConnectThread = null;
            }

            // Start the connected thread
            connected(mmSocket, mmDevice);
        }

        public void cancel() {
            try {
                mmSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of connect socket failed", e);
            }
        }
    }

    /**
     * This thread runs during a connection with a remote device.
     * It handles all incoming and outgoing transmissions.
     */
    private class ConnectedThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;

        public ConnectedThread(BluetoothSocket socket) {
            Log.d(TAG, "create ConnectedThread");
            mmSocket = socket;
            InputStream tmpIn = null;
            OutputStream tmpOut = null;

            // Get the BluetoothSocket input and output streams
            try {
                tmpIn = socket.getInputStream();
                tmpOut = socket.getOutputStream();
            } catch (IOException e) {
                Log.e(TAG, "temp sockets not created", e);
            }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;
        }

        @Override
        public void run() {
            Log.i(TAG, "BEGIN mConnectedThread");
            int bytes;

            // Keep listening to the InputStream while connected
            while (true) {
                try {
                    byte[] buffer = new byte[256];
                    // Read from the InputStream
                    bytes = mmInStream.read(buffer);
                    if(bytes>0)
                    {
                        // Send the obtained bytes to the UI Activity
                        mHandler.obtainMessage(PrintBluetooth.MESSAGE_READ, bytes, -1, buffer)
                                .sendToTarget();
                    }
                    else
                    {
                        Log.e(TAG, "disconnected");
                        connectionLost();

                        //add by chongqing jinou
                        if(mState != STATE_NONE)
                        {
                            Log.e(TAG, "disconnected");
                        // Start the service over to restart listening mode
                            BluetoothService.this.start();
                        }
                        break;
                    }
                } catch (IOException e) {
                    Log.e(TAG, "disconnected", e);
                    connectionLost();

                    //add by chongqing jinou
                    if(mState != STATE_NONE)
                    {
                        // Start the service over to restart listening mode
                        BluetoothService.this.start();
                    }
                    break;
                }
            }
        }

        /**
         * Write to the connected OutStream.
         * @param buffer  The bytes to write
         */
        public void write(byte[] buffer) {
            try {
                mmOutStream.write(buffer);
                mmOutStream.flush();//清空缓存
               /* if (buffer.length > 3000) //
                {
                  byte[] readata = new byte[1];
                  SPPReadTimeout(readata, 1, 5000);
                }*/
                Log.i("BTPWRITE", new String(buffer,"GBK"));
                // Share the sent message back to the UI Activity
                mHandler.obtainMessage(PrintBluetooth.MESSAGE_WRITE, -1, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "Exception during write", e);
            }
        }

        /*
        //
        private boolean SPPReadTimeout(byte[] Data, int DataLen, int Timeout){
          for (int i = 0; i < Timeout / 5; i++)
          {
            try
            {
              if (mmInStream.available() >= DataLen)
              {
                try
                {
                    mmInStream.read(Data, 0, DataLen);
                  return true;
                }
                catch (IOException e)
                {
                  ErrorMessage = "读取蓝牙数据失败";
                  return false;
                }
              }
            }
            catch (IOException e)
            {
              ErrorMessage = "读取蓝牙数据失败";
              return false;
            }
            try
            {
              Thread.sleep(5L);
            }
            catch (InterruptedException e)
            {
              ErrorMessage = "读取蓝牙数据失败";
              return false;
            }
          }
          ErrorMessage = "蓝牙读数据超时";
          return false;
        }
        */
        public void cancel() {
            try {
                mmSocket.close();
            } catch (IOException e) {
                Log.e(TAG, "close() of connect socket failed", e);
            }
        }
    }

---

您应该在后台维护蓝牙连接。将Bluetoothservice创建代码移动到android服务，并使用本地绑定器访问服务对象及其方法。

这就是我所做的，我正在寻找答案，但也无法工作，必须是硬件：(

03-23 11:17:08.639 15416-17471/in.juasoft.mobeeload E/BluetoothService: disconnected
                                                                        java.io.IOException: bt socket closed, read return: -1
                                                                            at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:578)
                                                                            at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:96)
                                                                            at java.io.InputStream.read(InputStream.java:162)
                                                                            at in.juasoft.mobeeload.BluetoothService$ConnectedThread.run(BluetoothService.java:387)
03-23 11:17:08.641 15416-17716/in.juasoft.mobeeload E/ERRROR :::::: INSIDE CATCH RUN