<uses-permission android:name="android.permission.BLUETOOTH"/> 
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> 
 
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 
 
 BluetoothSocket BTSocket; 
 BluetoothAdapter BTAdapter; 
 Button bt_start; 
 TextView tv_msg; 
 StringBuilder sb; 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 bt_start = (Button) findViewById(R.id.bt_start); 
 tv_msg = (TextView) findViewById(R.id.tv_msg); 
 bt_start.setOnClickListener(this); 
 sb = new StringBuilder(); 
 //拿到本地蓝牙设备 
 BTAdapter = BluetoothAdapter.getDefaultAdapter(); 
 } 
 
 /** 
 * UI文本输出 
 * 
 * @param msg 
 */ 
 public void show(String msg) { 
 sb.append(msg + "\n"); 
 runOnUiThread(new Runnable() { 
 @Override 
 public void run() { 
 tv_msg.setText(sb.toString()); 
 } 
 }); 
 } 
 
 @Override 
 public void onClick(View v) { 
 //开启服务器 
 ServerThread startServerThread = new ServerThread(); 
 startServerThread.start(); 
 } 
 
 /** 
 * 开启服务器 
 */ 
 private class ServerThread extends Thread { 
 public void run() { 
 try { 
 BluetoothServerSocket mserverSocket = BTAdapter.listenUsingRfcommWithServiceRecord("btspp", 
  UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")); 
 show("服务端:等待连接"); 
 
 BTSocket = mserverSocket.accept(); 
 show("服务端:连接成功"); 
 
 readThread mreadThread = new readThread(); 
 mreadThread.start(); 
 show("服务端:启动接受数据"); 
 } catch (IOException e) { 
 e.printStackTrace(); 
 } 
 } 
 } 
 
 /** 
 * 读取数据 
 */ 
 private class readThread extends Thread { 
 public void run() { 
 byte[] buffer = new byte[1024]; 
 int bytes; 
 InputStream mmInStream = null; 
 try { 
 mmInStream = BTSocket.getInputStream(); 
 show("服务端:获得输入流"); 
 } catch (IOException e1) { 
 e1.printStackTrace(); 
 } 
 while (true) { 
 try { 
  if ((bytes = mmInStream.read(buffer)) > 0) { 
  byte[] buf_data = new byte[bytes]; 
  for (int i = 0; i < bytes; i++) { 
  buf_data[i] = buffer[i]; 
  } 
  String s = new String(buf_data); 
  show("服务端:读取数据了~~" + s); 
  } 
 } catch (IOException e) { 
  try { 
  mmInStream.close(); 
  } catch (IOException e1) { 
  e1.printStackTrace(); 
  } 
  break; 
 } 
 } 
 } 
 } 
 
} 

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 
 
 private TextView tv_msg; 
 private Button bt_search, bt_send; 
 private BluetoothSocket BTSocket; 
 private BluetoothAdapter BTAdapter; 
 private BluetoothDevice device; 
 private StringBuilder sb; 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 
 bt_search = (Button) findViewById(R.id.bt_search); 
 bt_send = (Button) findViewById(R.id.bt_send); 
 tv_msg = (TextView) findViewById(R.id.tv_msg); 
 bt_search.setOnClickListener(this); 
 bt_send.setOnClickListener(this); 
 sb = new StringBuilder(); 
 
 show("客户端:检查BT"); 
 checkBT(this); 
 show("客户端:注册接收者"); 
 registerBTReceiver(); 
 } 
 
 /** 
 * UI文本输出 
 * 
 * @param msg 
 */ 
 public void show(String msg) { 
 sb.append(msg + "\n"); 
 runOnUiThread(new Runnable() { 
 @Override 
 public void run() { 
 tv_msg.setText(sb.toString()); 
 } 
 }); 
 } 
 
 @Override 
 public void onClick(View v) { 
 switch (v.getId()) { 
 case R.id.bt_search: 
 show("客户端:开始寻找设备"); 
 BTAdapter.startDiscovery(); 
 break; 
 case R.id.bt_send: 
 sendMessage(); 
 break; 
 } 
 } 
 
 /** 
 * 检查蓝牙 
 */ 
 public void checkBT(Context context) { 
 BTAdapter = BluetoothAdapter.getDefaultAdapter(); 
 if (BTAdapter != null) { 
 if (!BTAdapter.isEnabled()) { 
 Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); 
 // 设置蓝牙可见性，最多300秒 
 intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300); 
 context.startActivity(intent); 
 } 
 } else { 
 System.out.println("本地设备驱动异常!"); 
 } 
 } 
 
 /** 
 * 开启客户端 
 */ 
 private class clientThread extends Thread { 
 public void run() { 
 try { 
 //创建一个Socket连接：只需要服务器在注册时的UUID号 
 BTSocket = device.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")); 
 //连接 
 show("客户端:开始连接..."); 
 BTSocket.connect(); 
 show("客户端:连接成功"); 
 //启动接受数据 
 show("客户端:启动接受数据"); 
 readThread mreadThread = new readThread(); 
 mreadThread.start(); 
 } catch (IOException e) { 
 show("客户端:连接服务端异常！断开连接重新试一试"); 
 e.printStackTrace(); 
 } 
 } 
 } 
 
 /** 
 * 读取数据 
 */ 
 private class readThread extends Thread { 
 public void run() { 
 byte[] buffer = new byte[1024]; 
 int bytes; 
 InputStream is = null; 
 try { 
 is = BTSocket.getInputStream(); 
 show("客户端:获得输入流"); 
 } catch (IOException e1) { 
 e1.printStackTrace(); 
 } 
 while (true) { 
 try { 
  if ((bytes = is.read(buffer)) > 0) { 
  byte[] buf_data = new byte[bytes]; 
  for (int i = 0; i < bytes; i++) { 
  buf_data[i] = buffer[i]; 
  } 
  String s = new String(buf_data); 
  show("客户端:读取数据了" + s); 
  } 
 } catch (IOException e) { 
  try { 
  is.close(); 
  } catch (IOException e1) { 
  e1.printStackTrace(); 
  } 
  break; 
 } 
 } 
 } 
 } 
 
 /** 
 * 发送数据 
 */ 
 public void sendMessage() { 
 if (BTSocket == null) { 
 Toast.makeText(this, "没有连接", Toast.LENGTH_SHORT).show(); 
 return; 
 } 
 try { 
 OutputStream os = BTSocket.getOutputStream(); 
 os.write("我爱你dahsid132456@#%￥*".getBytes()); 
 os.flush(); 
 show("客户端:发送信息成功"); 
 } catch (IOException e) { 
 e.printStackTrace(); 
 } 
 } 
 
 /** 
 * 注册广播 
 */ 
 public void registerBTReceiver() { 
 // 设置广播信息过滤 
 IntentFilter intentFilter = new IntentFilter(); 
 intentFilter.addAction(BluetoothDevice.ACTION_FOUND); 
 intentFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED); 
 intentFilter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); 
 intentFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED); 
 intentFilter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED); 
 // 注册广播接收器，接收并处理搜索结果 
 registerReceiver(BTReceive, intentFilter); 
 } 
 
 /** 
 * 注销广播 
 */ 
 public void unregisterBTReceiver() { 
 unregisterReceiver(BTReceive); 
 } 
 
 @Override 
 protected void onDestroy() { 
 super.onDestroy(); 
 unregisterBTReceiver(); 
 } 
 
 /** 
 * 广播接收者 
 */ 
 private BroadcastReceiver BTReceive = new BroadcastReceiver() { 
 @Override 
 public void onReceive(Context context, Intent intent) { 
 String action = intent.getAction(); 
 if (BluetoothDevice.ACTION_FOUND.equals(action)) { 
 device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); 
 show("客户端:找到的BT名:" + device.getName()); 
 // 如果查找到的设备符合要连接的设备，处理 
 if (device.getName().equalsIgnoreCase("xu")) { 
  show("客户端:配对xu蓝牙:"); 
  // 搜索蓝牙设备的过程占用资源比较多，一旦找到需要连接的设备后需要及时关闭搜索 
  BTAdapter.cancelDiscovery(); 
  // 获取蓝牙设备的连接状态 
  int connectState = device.getBondState(); 
  switch (connectState) { 
  // 未配对 
  case BluetoothDevice.BOND_NONE: 
  show("客户端:开始配对:"); 
  try { 
  Method createBondMethod = BluetoothDevice.class.getMethod("createBond"); 
  createBondMethod.invoke(device); 
  } catch (Exception e) { 
  e.printStackTrace(); 
  } 
  break; 
  // 已配对 
  case BluetoothDevice.BOND_BONDED: 
  try { 
  show("客户端:开始连接:"); 
  clientThread clientConnectThread = new clientThread(); 
  clientConnectThread.start(); 
  } catch (Exception e) { 
  e.printStackTrace(); 
  } 
  break; 
  } 
 } 
 } else if (BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) { 
 // 获取蓝牙设备的连接状态 
 int connectState = device.getBondState(); 
 // 已配对 
 if (connectState == BluetoothDevice.BOND_BONDED) { 
  try { 
  show("客户端:开始连接:"); 
  clientThread clientConnectThread = new clientThread(); 
  clientConnectThread.start(); 
  } catch (Exception e) { 
  e.printStackTrace(); 
  } 
 } 
 } 
 show(action); 
 } 
 }; 
}