Android 蓝牙通信

Android 平台提供了完整的蓝牙 API，支持

传统蓝牙(Bluetooth Classic)和低功耗蓝牙(BBluetooth Low Energy, BLE)两种通信方式。

以下是开发蓝牙应用的关键知识点。

1. 基本概念

传统蓝牙(Bluetooth Classic)

• 适合大流量数据传输(如音频、文件传输)

• 典型协议: RFCOMM(串口模拟), A2DP(音频), HFP(免提)等

低功耗蓝牙(BLE)

• 适合间歇性小数据量传输，功耗低

• 典型应用: 健康设备、传感器、信标(Beacon)

2. 开发准备

清单文件配置

<!-- 蓝牙权限 -->
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" /><!-- 蓝牙扫描需要的位置权限(Android 6.0+) -->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /><!-- 仅用于Android 12+ -->
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" /><!-- 声明蓝牙功能 -->
<uses-feature android:name="android.hardware.bluetooth" android:required="true" />

运行时权限请求(Android 6.0+)

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION_PERMISSION);}
}

3. 传统蓝牙开发

检查并启用蓝牙

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();// 检查设备是否支持蓝牙
if (bluetoothAdapter == null) {// 设备不支持蓝牙return;
}// 检查蓝牙是否启用，如果未启用则请求启用
if (!bluetoothAdapter.isEnabled()) {Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}

发现设备

// 注册广播接收器监听发现的设备
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(receiver, filter);// 开始发现设备
bluetoothAdapter.startDiscovery();// 广播接收器示例
private final BroadcastReceiver receiver = new BroadcastReceiver() {public void onReceive(Context context, Intent intent) {String action = intent.getAction();if (BluetoothDevice.ACTION_FOUND.equals(action)) {BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);String deviceName = device.getName();String deviceAddress = device.getAddress();// 处理发现的设备}}
};// 停止发现
bluetoothAdapter.cancelDiscovery();

客户端连接(作为客户端)

// 假设已获取到BluetoothDevice对象
BluetoothDevice device = ...;// 使用UUID创建RFCOMM连接
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); // 标准串口UUID
BluetoothSocket socket = device.createRfcommSocketToServiceRecord(uuid);// 连接
try {socket.connect();// 连接成功，获取输入输出流InputStream inputStream = socket.getInputStream();OutputStream outputStream = socket.getOutputStream();// 进行数据读写outputStream.write("Hello".getBytes());byte[] buffer = new byte[1024];int bytes = inputStream.read(buffer);} catch (IOException e) {e.printStackTrace();
} finally {socket.close();
}

服务端监听(作为服务端)

// 创建监听socket
BluetoothServerSocket serverSocket = bluetoothAdapter.listenUsingRfcommWithServiceRecord("MyBluetoothApp", uuid);// 接受连接(应在后台线程执行)
try {BluetoothSocket socket = serverSocket.accept();// 连接建立，处理通信InputStream inputStream = socket.getInputStream();OutputStream outputStream = socket.getOutputStream();// 通信处理...} catch (IOException e) {e.printStackTrace();
} finally {serverSocket.close();
}

4. 低功耗蓝牙(BLE)开发

初始化BLE

BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter();// 检查BLE支持
if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {// 设备不支持BLEreturn;
}// 启用蓝牙(同传统蓝牙)

扫描BLE设备

// BLE扫描回调
private ScanCallback scanCallback = new ScanCallback() {@Overridepublic void onScanResult(int callbackType, ScanResult result) {BluetoothDevice device = result.getDevice();String deviceName = device.getName();String deviceAddress = device.getAddress();// 处理发现的设备}
};// 开始扫描
BluetoothLeScanner scanner = bluetoothAdapter.getBluetoothLeScanner();
List<ScanFilter> filters = new ArrayList<>(); // 可选过滤条件
ScanSettings settings = new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY).build();
scanner.startScan(filters, settings, scanCallback);// 停止扫描
scanner.stopScan(scanCallback);

连接BLE设备

// 蓝牙GATT回调
private BluetoothGattCallback gattCallback = new BluetoothGattCallback() {@Overridepublic void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {if (newState == BluetoothProfile.STATE_CONNECTED) {// 连接成功，发现服务gatt.discoverServices();} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {// 连接断开}}@Overridepublic void onServicesDiscovered(BluetoothGatt gatt, int status) {if (status == BluetoothGatt.GATT_SUCCESS) {// 服务发现完成，可以读写特征值List<BluetoothGattService> services = gatt.getServices();for (BluetoothGattService service : services) {List<BluetoothGattCharacteristic> characteristics = service.getCharacteristics();// 处理特征值}}}@Overridepublic void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {// 特征值读取完成byte[] data = characteristic.getValue();}@Overridepublic void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {// 特征值写入完成}@Overridepublic void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {// 特征值通知数据到达byte[] data = characteristic.getValue();}
};// 连接设备
BluetoothDevice device = ...; // 从扫描结果获取
BluetoothGatt gatt = device.connectGatt(context, false, gattCallback);// 断开连接
gatt.disconnect();
gatt.close();

读写BLE特征值

// 获取特征值对象(通常在onServicesDiscovered回调中)
BluetoothGattCharacteristic characteristic = ...;// 读取特征值
gatt.readCharacteristic(characteristic);// 写入特征值
characteristic.setValue("Hello".getBytes());
gatt.writeCharacteristic(characteristic);// 启用通知
gatt.setCharacteristicNotification(characteristic, true);
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")); // 客户端特征配置描述符
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
gatt.writeDescriptor(descriptor);

5. 常见问题

1. 权限问题：确保正确声明和请求所有必要权限

2. 蓝牙可用性：检查设备是否支持蓝牙/BLE功能

3. 连接稳定性：处理连接断开和重连逻辑

4. 线程管理：蓝牙操作应在后台线程执行

5. Android版本差异：不同Android版本API和行为可能有差异

6. 推荐库

1. Android-BLE-Library：简化BLE开发

2. FastBle：Android BLE框架

3. BluetoothHelper：传统蓝牙开发辅助库

结束。