BLE 介绍和使用

BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
BluetoothLeScanner bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();

ScanCallback scanCallback = new ScanCallback() {
    @Override
    public void onScanResult(int callbackType, ScanResult result) {
        super.onScanResult(callbackType, result);
        BluetoothDevice device = result.getDevice();
        // 发现目标设备后，停止扫描并连接
        if (device.getName() != null && device.getName().equals("TargetDeviceName")) {
            bluetoothLeScanner.stopScan(this);
            connectToDevice(device);
        }
        // 获取从设备的 MAC 地址
        String macAddress = device.getAddress();
        Log.d("BLE", "Found device MAC: " + macAddress);
    }
};

private void startScan() {
    bluetoothLeScanner.startScan(scanCallback);
}

private void connectToDevice(BluetoothDevice device) {
    device.connectGatt(this, false, gattCallback);
}

// 注册 BroadcastReceiver 监听配对请求
private void registerPairingReceiver() {
    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_PAIRING_REQUEST);
    registerReceiver(pairingReceiver, filter);
}

private final BroadcastReceiver pairingReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothDevice.ACTION_PAIRING_REQUEST.equals(action)) {
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            int pairingVariant = intent.getIntExtra(BluetoothDevice.EXTRA_PAIRING_VARIANT, BluetoothDevice.ERROR);

            if (pairingVariant == BluetoothDevice.PAIRING_VARIANT_PIN) {
                // 如果需要输入 PIN 码
                device.setPin("123456".getBytes());
                device.setPairingConfirmation(true);
            } else if (pairingVariant == BluetoothDevice.PAIRING_VARIANT_PASSKEY_CONFIRMATION) {
                // 如果需要确认 Passkey
                int passkey = intent.getIntExtra(BluetoothDevice.EXTRA_PAIRING_KEY, -1);
                Log.d("BLE", "Passkey: " + passkey);
                device.setPairingConfirmation(true);
            }
        }
    }
};

private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        if (newState == BluetoothProfile.STATE_CONNECTED) {
            Log.d("BLE", "Connected to GATT server.");
            gatt.discoverServices();
        } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
            Log.d("BLE", "Disconnected from GATT server.");
        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        if (status == BluetoothGatt.GATT_SUCCESS) {
            // 获取目标服务和特征值
            BluetoothGattService service = gatt.getService(UUID.fromString("0000180d-0000-1000-8000-00805f9b34fb")); // 替换为目标服务 UUID
            if (service != null) {
                BluetoothGattCharacteristic characteristic = service.getCharacteristic(UUID.fromString("00002a37-0000-1000-8000-00805f9b34fb")); // 替换为目标特征值 UUID
                if (characteristic != null) {
                    // 订阅通知
                    gatt.setCharacteristicNotification(characteristic, true);

                    // 配置特征值的通知描述符（如果需要）
                    BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
                    if (descriptor != null) {
                        descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
                        gatt.writeDescriptor(descriptor);
                    }
                }
            }
        }
    }

    @Override
    public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        // 当特征值的通知数据发生变化时触发
        byte[] data = characteristic.getValue();
        Log.d("BLE", "Received data: " + Arrays.toString(data));
    }
};

@Override
protected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(pairingReceiver);
    if (gatt != null) {
        gatt.close();
        gatt = null;
    }
}

private void connectToPairedDevice(String macAddress) {
    BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    BluetoothDevice device = bluetoothAdapter.getRemoteDevice(macAddress);

    if (device != null) {
        device.connectGatt(this, false, gattCallback);
    } else {
        Log.d("BLE", "Device not found!");
    }
}