Question

我正在做一个从传感器读取数据的程序。我在阅读这个特征时遇到了问题。我已经完成了debbug，我检查了方法onCharacteristicRead()从未被调用，我不明白为什么。有人可以帮帮我吗？在此先感谢!!

这是班级：

private Inter inter;
public final static String ACTION_DATA_AVAILABLE =
        "com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
        "com.example.bluetooth.le.EXTRA_DATA";
private static final String TAG = BluetoothLeService.class.getSimpleName();
//Services
private BluetoothGattService heartService;
//Characteristics
private BluetoothGattCharacteristic heartCharact;
private BluetoothGatt bluetoothGatt;

private final BluetoothGattCallback gattCallBack = new BluetoothGattCallback() {
    @Override
    public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        super.onCharacteristicWrite(gatt, characteristic, status);
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        super.onCharacteristicRead(gatt, characteristic, status);
        Log.d(TAG, "Entrei no onCharacteristicRead.");

        if (characteristic.getUuid().equals(DeviceConstants.HEART_RATE_MEASUREMENT)) {
            int flag = characteristic.getProperties();
            int format = -1;
            if ((flag & 0x01) != 0) {
                format = BluetoothGattCharacteristic.FORMAT_UINT16;
                Log.d(TAG, "Heart rate format UINT16.");
            } else {
                format = BluetoothGattCharacteristic.FORMAT_UINT8;
                Log.d(TAG, "Heart rate format UINT8.");
            }
            final int heartRate = characteristic.getIntValue(format, 1);
            Log.d(TAG, String.format("Received heart rate: %d", heartRate));
            getHeartRate(String.valueOf(heartRate));
        }
    }

    @Override
    public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        Log.d(TAG, "Entrou no Método: onServicesDiscovered");

        super.onServicesDiscovered(gatt, status);
        //BluetoothGattCharacteristic characteristic;

        if (status == BluetoothGatt.GATT_SUCCESS) {

            for (int i = 0; i != bluetoothGatt.getServices().size(); i++) {
                if (bluetoothGatt.getServices().get(i).getUuid().equals(DeviceConstants.HEART_RATE_SERVICE)) {
                    heartService = bluetoothGatt.getServices().get(i);
                }
            }
            for (int j = 0; j != heartService.getCharacteristics().size(); j++) {
                if (heartService.getCharacteristics().get(j).getUuid().equals(DeviceConstants.HEART_RATE_MEASUREMENT)) {
                    Log.d(TAG, "Entrou no if 2");
                    heartService = bluetoothGatt.getService(DeviceConstants.HEART_RATE_SERVICE);
                    heartCharact = heartService.getCharacteristic(DeviceConstants.HEART_RATE_MEASUREMENT);
                    //heartCharact.setValue(1, BluetoothGattCharacteristic.FORMAT_UINT8, 0);
                    //bluetoothGatt.writeCharacteristic(heartCharact);
                    //bluetoothGatt.readCharacteristic(heartCharact);
                    Log.d(TAG, "WOOOOOW:  " + heartCharact);
                }
            }
        }
        bluetoothGatt.readCharacteristic(heartCharact);
    }

    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        super.onConnectionStateChange(gatt, status, newState);

        if (newState == BluetoothProfile.STATE_CONNECTING) {
            Log.d(TAG, "Connecting to " + gatt.getDevice().getName() + ", please wait...");
        }
        if (newState == BluetoothProfile.STATE_CONNECTED) {
            Log.d(TAG, "Connected!!");
            bluetoothGatt.discoverServices();

        }
    }

    public void getHeartRate(String hr) {
        inter.getHeartRate(hr);
    }

    private void broadcastUpdate(final String action, final BluetoothGattCharacteristic characteristic) {
        final Intent intent = new Intent(action);

        if (DeviceConstants.HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
            int flag = characteristic.getProperties();
            int format = -1;
            if ((flag & 0x01) != 0) {
                format = BluetoothGattCharacteristic.FORMAT_UINT16;
                Log.d(TAG, "Heart rate format UINT16.");
            } else {
                format = BluetoothGattCharacteristic.FORMAT_UINT8;
                Log.d(TAG, "Heart rate format UINT8.");
            }
            final int heartRate = characteristic.getIntValue(format, 1);
            Log.d(TAG, String.format("Received heart rate: %d", heartRate));
            intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
        } else {
            final byte[] data = characteristic.getValue();
            if (data != null && data.length > 0) {
                final StringBuilder stringBuilder = new StringBuilder(data.length);
                for (byte byteChar : data)
                    stringBuilder.append(String.format("%02X ", byteChar));
                intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
            }
        }
        sendBroadcast(intent);
    }
};

private BluetoothDevice device;
private Context context;

public BluetoothLeService(BluetoothDevice device, Context context, Inter inter) {
    this.device = device;
    this.context = context;
    this.inter = inter;
}

public void connect() {
    bluetoothGatt = device.connectGatt(context, false, gattCallBack);
    Log.d(TAG, "Entrou no Método: connect");
}

public void disconnect() {
    bluetoothGatt.disconnect();
}

Answer 1

这是因为某些特征不可读。

查看此页面：https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.service.heart_rate.xml

您将看不到此属性：＆＃34;读取排除＆＃34;。

您应该注册，然后将调用您的onCharacteristicChanged回调。

Android BLE：未调用onCharacteristicRead（）

1 个答案: