Android蓝牙连接ESC/POS热敏打印机打印实例（蓝牙连接篇）

 
 
 
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BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
 // Device does not support Bluetooth
}

if (!mBluetoothAdapter.isEnabled()) {
 Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
 startActivityForResult(intent, REQUEST_ENABLE_BT);
}

mBluetoothAdapter.startDiscovery();

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
 public void onReceive(Context context, Intent intent) {
  String action = intent.getAction();

  // 当有设备被发现的时候会收到 action == BluetoothDevice.ACTION_FOUND 的广播
  if (BluetoothDevice.ACTION_FOUND.equals(action)) {

   //广播的 intent 里包含了一个 BluetoothDevice 对象
   BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

   //假设我们用一个 ListView 展示发现的设备，那么每收到一个广播，就添加一个设备到 adapter 里
   mArrayAdapter.add(device.getName() + "\n" + device.getAddress());
  }
 }
};
// 注册广播监听
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter); // Don't forget to unregister during onDestroy

Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
//设置可被发现的时间，00s
intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(intent);

Set pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
 for (BluetoothDevice device : pairedDevices) {
  mArrayAdapter.add(device.getName() + "\n" + device.getAddress());
 }
}

private class ConnectThread extends Thread {
 private final BluetoothSocket mmSocket;
 private final BluetoothDevice mmDevice;

 public ConnectThread(BluetoothDevice device) {

  BluetoothSocket tmp = null;
  mmDevice = device;
  try {
   // 通过 BluetoothDevice 获得 BluetoothSocket 对象
   tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
  } catch (IOException e) { }
  mmSocket = tmp;
 }

 @Override
 public void run() {
  // 建立连接前记得取消设备发现
  mBluetoothAdapter.cancelDiscovery();
  try {
   // 耗时操作，所以必须在主线程之外进行
   mmSocket.connect();
  } catch (IOException connectException) {
   //处理连接建立失败的异常
   try {
    mmSocket.close();
   } catch (IOException closeException) { }
   return;
  }
  doSomething(mmSocket);
 }

 //关闭一个正在进行的连接
 public void cancel() {
  try {
   mmSocket.close();
  } catch (IOException e) { }
 }
}

private class AcceptThread extends Thread {

 private final BluetoothServerSocket mmServerSocket;

 public AcceptThread() {

  BluetoothServerSocket tmp = null;
  try {
   // client 必须使用一样的 UUID !!!
   tmp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
  } catch (IOException e) { }
  mmServerSocket = tmp;
 }

 @Override
 public void run() {
  BluetoothSocket socket = null;
  //阻塞操作
  while (true) {
   try {
    socket = mmServerSocket.accept();
   } catch (IOException e) {
    break;
   }
   //直到有有连接建立，才跳出死循环
   if (socket != null) {
    //要在新开的线程执行，因为连接建立后，当前线程可能会关闭
    doSomething(socket);
    mmServerSocket.close();
    break;
   }
  }
 }

 public void cancel() {
  try {
   mmServerSocket.close();
  } catch (IOException e) { }
 }
}

private class ConnectedThread extends Thread {
 private final BluetoothSocket mmSocket;
 private final InputStream mmInStream;
 private final OutputStream mmOutStream;

 public ConnectedThread(BluetoothSocket socket) {
  mmSocket = socket;
  InputStream tmpIn = null;
  OutputStream tmpOut = null;
  //通过 socket 得到 InputStream 和 OutputStream
  try {
   tmpIn = socket.getInputStream();
   tmpOut = socket.getOutputStream();
  } catch (IOException e) { }

  mmInStream = tmpIn;
  mmOutStream = tmpOut;
 }

 public void run() {
  byte[] buffer = new byte[1024]; // buffer store for the stream
  int bytes; // bytes returned from read()

  //不断的从 InputStream 取数据
  while (true) {
   try {
    bytes = mmInStream.read(buffer);
    mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)
      .sendToTarget();
   } catch (IOException e) {
    break;
   }
  }
 }

 //向 Server 写入数据
 public void write(byte[] bytes) {
  try {
   mmOutStream.write(bytes);
  } catch (IOException e) { }
 }

 public void cancel() {
  try {
   mmSocket.close();
  } catch (IOException e) { }
 }
}