Android BLE 数据写入问题 - 出现错误 133

Question

在过去的 6 个月里，我一直致力于 BLE 应用程序。 在我最近的项目中，我正在集成一个自定义 BLE 设备，它在读取数据时会出现同步问题。 “onCharacteristicRead”总是返回 133 错误代码。请通过完整的场景，如果有人有任何解决方案，请帮助我。

场景 定制 BLE 设备提供三种服务。

1. 紧急情况

2. 一目了然

3. 电池电量

我的应用程序中只需要两个服务。电池和紧急情况。 最初，我将使用以下代码扫描设备，

 private void scan() {
        if (isLollyPopOrAbove()) {// Start Scanning For Lollipop devices
            mBluetoothAdapter.getBluetoothLeScanner().startScan(scanFilters(), scanSettings(), scanCallback); // Start BLE device Scanning in a separate thread
        } else {
            mBluetoothAdapter.startLeScan(mLeScanCallback); // Start Scanning for Below Lollipop device
        }
    }




   private List<ScanFilter> scanFilters() {
        String emergencyUDID = "3C02E2A5-BB87-4BE0-ADA5-526EF4C14AAA";
        ScanFilter filter = new ScanFilter.Builder().setServiceUuid(ParcelUuid.fromString(emergencyUDID)).build();
        List<ScanFilter> list = new ArrayList<ScanFilter>(1);
        list.add(filter);
        return list;
    }



   private ScanSettings scanSettings() {
        ScanSettings settings = new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_BALANCED).build();
        return settings;
    }

这工作正常，我正在获得扫描结果，我可以连接到设备。建立连接后，我将从 GattCallBack 进行以下调用

mBluetoothGatt.discoverServices();

然后我得到服务发现完成回调

   @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {              //BLE service discovery complete
            if (status == BluetoothGatt.GATT_SUCCESS) {                                 //See if the service discovery was successful
                Log.i(TAG, "**ACTION_SERVICE_DISCOVERED**" + status);
                broadcastUpdate(BLEConstants.ACTION_GATT_SERVICES_DISCOVERED);                       //Go broadcast an intent to say we have discovered services
            } else {                                                                      //Service discovery failed so log a warning
                Log.i(TAG, "onServicesDiscovered received: " + status);
            }
        }

从这里我找到使用提供的 UUID 的可用 MLDP 服务。这也很好用。

但是当我阅读特征时，

public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
        if (mBluetoothAdapter == null || mBluetoothGatt == null) {                      //Check that we have access to a Bluetooth radio
            return;
        }
        boolean status = mBluetoothGatt.readCharacteristic(characteristic);                              //Request the BluetoothGatt to Read the characteristic
        Log.i(TAG, "READ STATUS " + status);
    }

响应状态为真，但“onCharacteristicRead”回调始终为 133

 @Override
        public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) { //A request to Read has completed
            //String value = characteristic.getStringValue(0);
            //int value = characteristic.getIntValue(BluetoothGattCharacteristic.FORMAT_UINT32, 0);
//            if(characteristic.getUuid().e)
                if (status == BluetoothGatt.GATT_SUCCESS) {
                    //See if the read was successful
                    Log.i(TAG, "**ACTION_DATA_READ**" + characteristic);
                    broadcastUpdate(BLEConstants.ACTION_DATA_AVAILABLE, characteristic);                 //Go broadcast an intent with the characteristic data
                } else {
                    Log.i(TAG, "ACTION_DATA_READ: Error" + status);
                }


        }

Answer 1

最后，我找到了处理 133 错误的解决方案。在深入分析的过程中，我发现BLE请求响应过程有一些延迟。所以我为每次读取和写入设置了 500 毫秒的延迟。现在它工作得很好。我已经在各种设备上对其进行了测试及其工作。我不知道这是否是一种解决方法。但这可能对面临类似问题的开发人员有所帮助。

Answer 2

错误代码：133 表示 GATT__ERROR，设备不在范围内。在读取事件期间可能存在错误。我建议请先从设备端检查。

一个问题：这个设备需要绑定才能连接吗？