Android BLE 特性 setValue 无法写入正确的数据

Question

我正在尝试开发一个 Android 应用程序，它使用 BLE 连接到我基于 NRF51822 的系统。目的是将 3 字节值 (RGB) 写入我的自定义特征。

Android 是 GATT 客户端，基于 NRF51 的设备是 GATT 服务器。

我能够成功地建立 ble 连接并发现我的特征。

但是数据发送部分(setValue)给我带来了麻烦。无论我写什么 3 个字节，我在 NRF51 端得到相同的常量数据

下面是我的相关代码(Android)

 @Override
 public void onServicesDiscovered(BluetoothGatt gatt, int status) {
       Log.d("BLENotifier", "BLE GAT : SERVICES DISCOVERED");
       for(BluetoothGattService gs: gatt.getServices()) {
           Log.d("BLENotifier", "SERVICE = " + gs.getUuid().toString());
       }
       //SELECT MY CHARACTERSTIC
       ble_my_characterstic = gatt.getService(ble_service_uuid).getCharacteristic(ble_characterstic_uuid);
       Log.d("BLENotifier", "BLE SELECTED CHARACTERSTIC " + ble_my_characterstic.getUuid().toString());
       ble_connected = true;
    }

public void writedata(String data){
    //WRITE DATA TO MY CHARACTERSTIC
    if(ble_my_characterstic != null && ble_connected == true){

        my_gatt_handle.executeReliableWrite();
        //ble_my_characterstic.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_NO_RESPONSE);
        ble_my_characterstic.setValue(hexStringToByteArray(data));
        my_gatt_handle.writeCharacteristic(ble_my_characterstic);

        Log.d("BLENotifier", "BLE WRITE DATA " + data);
    }

public static byte[] hexStringToByteArray(String s) {
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                + Character.digit(s.charAt(i+1), 16));
    }
    Log.d("BLENotifier", "hexStringToByteArray " + Integer.toString((int)data[0]) + " " + Integer.toString((int)data[1]) + " " + Integer.toString((int)data[2]));
    return data;
}

我调用 writeData 方法作为 ble_handle.writedata("0000FF")

这是我在 NRF51 方面得到的

R = 4 | G = 239 | B= 1

谢谢

Answer 1

I did like this.Not exact answer but may help you.

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) 
    {
        List<BluetoothGattService> services = gatt.getServices();
        Log.i("onServicesDiscovered", services.toString());
        keepConnect=services.get(3).getCharacteristics().get(0);
        if(keepConnect!=null){
            writeCharacteristic(gatt,keepConnect);
        }
    }

    private void writeCharacteristic(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic)
    {

        byte[] byteData = hexToBytes("6fd362e40ebcd0945bf58dc4");
        byte[] writeData = new byte[byteData.length];
        for (int i = 0; i < byteData.length; i++) {
            writeData[i] = byteData[i];
        }
        characteristic.setValue(writeData);
        gatt.writeCharacteristic(characteristic);       

    }

public static byte[] hexToBytes(String hexRepresentation) {
    int len = hexRepresentation.length();
    byte[] data = new byte[len / 2];

    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(hexRepresentation.charAt(i), 16) << 4)
                + Character.digit(hexRepresentation.charAt(i + 1), 16));
    }

    return data;
}