Question

由于我正在为Android开发一个小型蓝牙库，我正在尝试获取我周围发现的设备的所有服务uuids。

当我的广播接收器获得BluetoothDevice.ACTION_FOUND意图时，我正在提取设备并致电：

device.fetchUuidsWithSdp();

这将导致找到每个设备的BluetoothDevice.ACTION_UUID意图，并且我使用相同的接收器处理它们：

BluetoothDevice d = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Parcelable[] uuidExtra = intent.getParcelableArrayExtra(BluetoothDevice.EXTRA_UUID);

if(uuidExtra ==  null) {
    Log.e(TAG, "UUID = null");
}

if(d != null && uuidExtra != null)
    Log.d(TAG, d.getName() + ": " + uuidExtra.toString());

问题是，uuidExtra总是null。

如何获取周围设备的所有UUID？

编辑：

我正在使用Nexus 7.我尝试了在互联网上找到的代码，这也给了我一个NullPointerException：http://digitalhacksblog.blogspot.de/2012/05/android-example-bluetooth-discover-and.html

谢谢。

Answer 1

documentation就此状态......

始终包含额外字段BluetoothDevice.EXTRA_UUID

但是，就像你一样，我发现这不是真的。

如果您在设备发现仍在进行时致电fetchUuidsWithSdp() BluetoothDevice.EXTRA_UUID可能为空。

在拨打BluetoothAdapter.ACTION_DISCOVERY_FINISHED之前，您应该等到收到fetchUuidsWithSdp()。

Answer 2

注意：此解决方案适用于CLASSIC蓝牙而非BLE。对于BLE，请检查如何发送制造商特定的外围广告商数据

获取Uuids的问题是你只有一个蓝牙适配器，我们不能进行并行api调用，它们使用适配器。

正如Eddie指出的那样，等待BluetoothAdapter.ACTION_DISCOVERY_FINISHED，然后致电fetchUuidsWithSdp()。

仍然无法保证为所有设备提取uuids。除此之外，必须等待对fetchuuidsWithSdp()的每个后续调用完成，然后为另一个设备调用此方法。

请参阅以下代码 -

ArrayList<BluetoothDevice> mDeviceList = new ArrayList<BluetoothDevice>();

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

        if (BluetoothDevice.ACTION_FOUND.equals(action)) {
            BluetoothDevice device = (BluetoothDevice) intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            mDeviceList.add(device);
        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
            // discovery has finished, give a call to fetchUuidsWithSdp on first device in list.
            if (!mDeviceList.isEmpty()) {
                BluetoothDevice device = mDeviceList.remove(0);
                boolean result = device.fetchUuidsWithSdp();
            }
        } else if (BluetoothDevice.ACTION_UUID.equals(action)) {
            // This is when we can be assured that fetchUuidsWithSdp has completed.
            // So get the uuids and call fetchUuidsWithSdp on another device in list

            BluetoothDevice deviceExtra = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            Parcelable[] uuidExtra = intent.getParcelableArrayExtra(BluetoothDevice.EXTRA_UUID);
            System.out.println("DeviceExtra address - " + deviceExtra.getAddress());
            if (uuidExtra != null) {
                for (Parcelable p : uuidExtra) {
                    System.out.println("uuidExtra - " + p);
                }
            } else {
                System.out.println("uuidExtra is still null");
            }
            if (!mDeviceList.isEmpty()) {
                BluetoothDevice device = mDeviceList.remove(0);
                boolean result = device.fetchUuidsWithSdp();
            }
        }
    }
}

更新：最新的Android版本（mm及以上）会导致触发与每个设备的配对过程

Answer 3

我想您需要与设备配对才能接收uuids。至少，这就是发生在我身上的事。

Answer 4

以下是如何从我为获取心率设备所做的服务中获取服务特征的UUID的一个很好的示例：

private class HeartRateBluetoothGattCallback extends BluetoothGattCallback {

    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {         
        if (newState == BluetoothProfile.STATE_CONNECTED) {
            logMessage("CONNECTED TO " + gatt.getDevice().getName(), false, false);
            gatt.discoverServices();    
        } else if(newState == BluetoothProfile.STATE_DISCONNECTED) {
            logMessage("DISCONNECTED FROM " + gatt.getDevice().getName(), false, false);
            if(mIsTrackingHeartRate)
                handleHeartRateDeviceDisconnection(gatt);
        } 
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        if (status == BluetoothGatt.GATT_SUCCESS) {
            logMessage("DISCOVERING SERVICES FOR " + gatt.getDevice().getName(), false, false);

            if(mDesiredHeartRateDevice != null && 
                    gatt.getDevice().getAddress().equals(mDesiredHeartRateDevice.getBLEDeviceAddress())) {

                if(subscribeToHeartRateGattServices(gatt)) {

                    mIsTrackingHeartRate = true;
                    setDeviceScanned(getDiscoveredBLEDevice(gatt.getDevice().getAddress()), DiscoveredBLEDevice.CONNECTED);
                    broadcastHeartRateDeviceConnected(gatt.getDevice());

                } else
                    broadcastHeartRateDeviceFailedConnection(gatt.getDevice());

            } else {
                parseGattServices(gatt);
                disconnectGatt(getDiscoveredBLEDevice(gatt.getDevice().getAddress()));
            }
        }   
    }

    @Override
    public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        if(characteristic.getUuid().equals(UUID.fromString(HEART_RATE_VALUE_CHAR_READ_ID))) {
            int flag = characteristic.getProperties();
            int format = -1;

            if ((flag & 0x01) != 0) 
                format = BluetoothGattCharacteristic.FORMAT_UINT16;
            else 
                format = BluetoothGattCharacteristic.FORMAT_UINT8;

            Integer heartRateValue = characteristic.getIntValue(format, 1);
            if(heartRateValue != null)
                broadcastHeartRateValue(heartRateValue);
            else
                Log.w(SERVICE_NAME, "UNABLE TO FORMAT HEART RATE DATA");
        }
    };

};

private void parseGattServices(BluetoothGatt gatt) {
    boolean isHeartRate = false;
    for(BluetoothGattService blueToothGattService : gatt.getServices()) {
        logMessage("GATT SERVICE: " + blueToothGattService.getUuid().toString(), false, false);
        if(blueToothGattService.getUuid().toString().contains(HEART_RATE_DEVICE_SERVICE_CHARACTERISTIC_PREFIX))
            isHeartRate = true;
    }   

    if(isHeartRate) {
        setDeviceScanned(getDiscoveredBLEDevice(gatt.getDevice().getAddress()), DiscoveredBLEDevice.IS_HEART_RATE);
        broadcastHeartRateDeviceFound(getDiscoveredBLEDevice(gatt.getDevice().getAddress()));
    } else 
        setDeviceScanned(getDiscoveredBLEDevice(gatt.getDevice().getAddress()), DiscoveredBLEDevice.NOT_HEART_RATE);
}

private void handleHeartRateDeviceDisconnection(BluetoothGatt gatt) {
    broadcastHeartRateDeviceDisconnected(gatt.getDevice());
    gatt.close();

    clearoutHeartRateData();
    scanForHeartRateDevices();
}

private void disconnectGatt(DiscoveredBLEDevice device) {
    logMessage("CLOSING GATT FOR " + device.getBLEDeviceName(), false, false);
    device.getBlueToothGatt().close();
    device.setBlueToothGatt(null);
    mInDiscoveryMode = false;
}

private boolean subscribeToHeartRateGattServices(BluetoothGatt gatt) {
    for(BluetoothGattService blueToothGattService : gatt.getServices()) {
        if(blueToothGattService.getUuid().toString().contains(HEART_RATE_DEVICE_SERVICE_CHARACTERISTIC_PREFIX)) {
            mHeartRateGattService = blueToothGattService;

            for(BluetoothGattCharacteristic characteristic : mHeartRateGattService.getCharacteristics()) {
                logMessage("CHARACTERISTIC UUID = " + characteristic.getUuid().toString(), false, false);

                for(BluetoothGattDescriptor descriptor :characteristic.getDescriptors()) {
                    logMessage("DESCRIPTOR UUID = " + descriptor.getUuid().toString(), false, false);
                }

                if(characteristic.getUuid().equals(UUID.fromString(HEART_RATE_VALUE_CHAR_READ_ID))) {
                    gatt.setCharacteristicNotification(characteristic, true);
                    BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString(HEART_RATE_VALUE_CHAR_DESC_ID));
                    descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
                    return gatt.writeDescriptor(descriptor);
                }
            }

            break; //break out of master for-loop
        }
    }

    return false;
}

Answer 5

device.getUuids（）使用此命令以ParcelUuid的形式获取该配对设备的所有uuid。下面的示例代码：-

private void get_uuid_from_paired_devices(){
        Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
        for (BluetoothDevice device: pairedDevices){

            for (ParcelUuid uuid: device.getUuids()){
                String uuid_string = uuid.toString();
                Log.d(TAG, "uuid : "+uuid_string);
            }
        }
    }

Answer 6

以下是我从远程设备获取记录

的工作原理

-0-
registerReceiver(..,
                new IntentFilter(BluetoothDevice.ACTION_UUID));

-1- device.fetchUuidsWithSdp（）;

-2 - 来自广域接收器

   if (BluetoothDevice.ACTION_UUID.equals(action)) {
                        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                        Parcelable[] uuids = intent.getParcelableArrayExtra(BluetoothDevice.EXTRA_UUID);
                        for (Parcelable ep : uuids) {
                            Utilities.print("UUID records : "+ ep.toString());
                        }
                    }

您还可以使用

获取离线缓存的UUID记录

 BluetoothDevice.getUuids();

Android蓝牙：获取已发现设备的UUID

6 个答案: