android - 在 Android 中连续读取 BLE 的值

Question

我正在尝试从 Android 设备与 BLE 交互并读取一些传感器值，我遵循 API 级别 > 21。我设法扫描设备并连接到它。第一个挑战是一次读取所有特征值，有人建议使用优先级队列来做到这一点，我以明智的方式实现并且工作正常。

BluetoothGattCallback gattCallBack = new BluetoothGattCallback() {
        @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        switch (newState) {
            case BluetoothProfile.STATE_CONNECTED:
                Log.d(TAG, "STATE_CONNECTED");
                bluetoothGatt.discoverServices();
                break;
            case BluetoothProfile.STATE_DISCONNECTED:
                Log.d(TAG, "STATE_DISCONNECTED");
                break;
            default:
                Log.d(TAG, "STATE_OTHER");

        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        final List<BluetoothGattService> services = gatt.getServices();
        characteristics = new ArrayList<BluetoothGattCharacteristic>();
        characteristics.add(services.get(1).getCharacteristics().get(0));
        characteristics.add(services.get(1).getCharacteristics().get(1));
        characteristics.add(services.get(1).getCharacteristics().get(2));

        characteristics.add(services.get(2).getCharacteristics().get(0));
        characteristics.add(services.get(2).getCharacteristics().get(1));
        characteristics.add(services.get(2).getCharacteristics().get(2));

        characteristics.add(services.get(3).getCharacteristics().get(0));
        characteristics.add(services.get(3).getCharacteristics().get(1));
        characteristics.add(services.get(3).getCharacteristics().get(2));
        requesReadCharacteristics(gatt);
    }

    public void requesReadCharacteristics(BluetoothGatt gatt) {
        gatt.readCharacteristic(characteristics.get(characteristics.size() - 1));
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        if (status == 0 ) {
            Log.d(TAG, "DeviceNameFetchFromDevice: " + characteristic.getValue());
            characteristics.remove(characteristics.get(characteristics.size() - 1));

            if (characteristics.size() > 0) {
                requesReadCharacteristics(gatt);
            } else {
                gatt.disconnect();
            }
        }
    }

    @Override
    public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        super.onCharacteristicWrite(gatt, characteristic, status);
    }
};

现在我需要通过 BLE 设备持续监控读取传感器值(比如每隔 10 秒)，所以我需要反复读取特征值并获取它们的值。但是 ble 不允许在第一次调用后调用“readCharacteristic”。

现在我已经实现了它，定期调用 connectDevice(BluetoothDevice)，这就像断开与 BLE 设备的现有连接并再次连接它。有什么方法可以让我们反复调用 readCharacteristic 连接到设备。根据我的理解，断开和连接设备并不是那么有效。请让我知道，如果有这样的例子，什么是继续读取设备或分享的正确方法

https://github.com/sandeeptengale/androidble/

Answer 1

首先，你应该打开通知:

mBluetoothLeService.setCharacteristicNotification(characteristic, true);

然后，当数据改变时，你可以在这个方法中读取值:

onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic)