蓝牙外设ADVERTISE_FAILED_DATA_TOO_LARGE

Question

我试图在NEXUS 9中做广告并得到ADVERTISE_FAILED_DATA_TOO_LARGE的错误.在成功通告后添加服务时,它工作得非常好但是如果我通过"广告数据"构建器添加服务以便其他设备可以在扫描时进行过滤,则会收到错误代码1,即ADVERTISE_FAILED_DATA_TOO_LARGE

a)工作准则

     public void startAdvertisingService() {
    AdvertiseSettings settings = new AdvertiseSettings.Builder()
            .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH)
            .setTimeout(0)
            .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY)      
            .build();


     AdvertiseData.Builder advertiseData = new AdvertiseData.Builder();
    advertiseData.setIncludeDeviceName(true);

     BluetoothLeAdvertiser myBluetoothLeAdvertiser = btAdapter.getBluetoothLeAdvertiser();
      myBluetoothLeAdvertiser.stopAdvertising(mAdvertiseCallback);

    myBluetoothLeAdvertiser.startAdvertising(settings, advertiseData.build(),mAdvertiseCallback);

   }
    private AdvertiseCallback mAdvertiseCallback = new AdvertiseCallback() {

    @Override
    public void onStartSuccess(AdvertiseSettings settingsInEffect) {
        super.onStartSuccess(settingsInEffect);
        BLEBroadcast();
    }

    @Override
    public void onStartFailure(int errorCode) {
        String description = "";
        if (errorCode == AdvertiseCallback.ADVERTISE_FAILED_FEATURE_UNSUPPORTED)
            description = "ADVERTISE_FAILED_FEATURE_UNSUPPORTED";
        else if (errorCode == AdvertiseCallback.ADVERTISE_FAILED_TOO_MANY_ADVERTISERS)
            description = "ADVERTISE_FAILED_TOO_MANY_ADVERTISERS";
        else if (errorCode == AdvertiseCallback.ADVERTISE_FAILED_ALREADY_STARTED)
            description = "ADVERTISE_FAILED_ALREADY_STARTED";
        else if (errorCode == AdvertiseCallback.ADVERTISE_FAILED_DATA_TOO_LARGE)
            description = "ADVERTISE_FAILED_DATA_TOO_LARGE";
        else if (errorCode == AdvertiseCallback.ADVERTISE_FAILED_INTERNAL_ERROR)
            description = "ADVERTISE_FAILED_INTERNAL_ERROR";
        else description = "unknown";

    }
};

并且还添加了服务:

 void BLEBroadcast() {

    BluetoothGattCharacteristic characteristic = new     BluetoothGattCharacteristic(characteristicUUID, BluetoothGattCharacteristic.PROPERTY_NOTIFY | BluetoothGattCharacteristic.PROPERTY_INDICATE | BluetoothGattCharacteristic.PROPERTY_READ | BluetoothGattCharacteristic.PROPERTY_WRITE, BluetoothGattCharacteristic.PERMISSION_READ | BluetoothGattCharacteristic.PERMISSION_WRITE);

    BluetoothGattDescriptor desc = new BluetoothGattDescriptor(descriptorUUID, BluetoothGattDescriptor.PERMISSION_READ | BluetoothGattDescriptor.PERMISSION_WRITE);
    desc.setValue("".getBytes());

    characteristic.addDescriptor(desc);

    BluetoothGattService service = new BluetoothGattService(serviceUUID,     BluetoothGattService.SERVICE_TYPE_PRIMARY);
    service.addCharacteristic(characteristic);

    mGattServer.addService(service);
 }

b)最初添加服务时不起作用,以便中央通过过滤器发现:

在调用BLEBroadcast()之前调用函数startAdvertisingService()并添加

        AdvertiseData.Builder advertiseData = new AdvertiseData.Builder();
        advertiseData.addServiceUuid(new ParcelUuid(serviceUUID)); 

出现广告失败,错误代码为1.

Answer 1

我怀疑这是引起麻烦的代码行:

advertiseData.setIncludeDeviceName(true);

广告将没有足够的空间用于设备名称和16字节服务UUID.因此,如果您包含上述内容,请添加:

advertiseData.addServiceUuid(new ParcelUuid(serviceUUID)); 

您将收到您描述的错误.尝试删除第一行.

Answer 2

基本上你的数据超过了 31 个字节，所以你需要修剪它。

将其更改为 false，然后它就可以工作：

advertiseData.setIncludeDeviceName(false);