How to fix Android BLE SCAN_FAILED_APPLICATION_REG

问题:

Most of times it works great but sometimes i'm having this error while trying to discover BLE devices:

02-12 18:00:41.952  16178-16339/com.icrealtime.allie W/BleRpcConnectionFactory﹕ Starting discovery
02-12 18:00:41.955  16178-16339/com.icrealtime.allie D/BluetoothAdapter﹕ STATE_ON
02-12 18:00:41.957  24342-18813/? D/BtGatt.GattService﹕ registerClient() - UUID=c4a4c56d-1d10-4615-9c8d-44971bc3d6e6
02-12 18:00:41.957  24342-24384/? E/bt_btif﹕ Register with GATT stack failed.
02-12 18:00:41.957  24342-24384/? E/bt_btif﹕ Register with GATT stack failed.
02-12 18:00:41.957  24342-24370/? D/BtGatt.GattService﹕ onClientRegistered() - UUID=c4a4c56d-1d10-4615-9c8d-44971bc3d6e6, clientIf=0
02-12 18:00:41.958  16178-16190/com.icrealtime.allie D/BluetoothLeScanner﹕ onClientRegistered() - status=133 clientIf=0
02-12 18:00:41.967  16178-16178/com.icrealtime.allie E/BleRpcConnectionFactory﹕ BLE SCAN FAILED: 2

error code 2 stands for https://developer.android.com/reference/android/bluetooth/le/ScanCallback.html#SCAN_FAILED_APPLICATION_REGISTRATION_FAILED

It seems to be internal android issue, but it can be affected by my code doing something wrong. What can be the reason and how to walkaround it?

PS. Nexus 9, Android 6.0.1

回答1:

A possible workaround it might be to disable/enable the blueetooth programmatically. When you got the error SCAN_FAILED_APPLICATION_REGISTRATION_FAILED you should disable the BluetoothAdapter:

BluetoothAdapter.getDefaultAdapter().disable();

Disabling BluetoothAdapter, the event STATE_TURNING_OFF is fired. Once this event is fired, try to reconnect to the BluetoothAdapter:

case BluetoothAdapter.STATE_OFF:
  Log.d(TAG, "bluetooth adapter turned off");
  handler.postDelayed(new Runnable() {
    @Override
    public void run() {
        Log.d(TAG, "bluetooth adapter try to enable");
        BluetoothAdapter.getDefaultAdapter().enable();
    }}, 500);
  break;

回答2:

Ideally, please look into the phone's location services support (Android 6+ BLE services require it be on for proper functionality). We've seen this issue on other occasions with Cordova plugins. Turn on location services (or check that these are turned on).

回答3:

you need to add following permission in the manifest:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-feature android:name="android.hardware.location.network"/>

If not the coarse location will not be able to access network and so the LeScan break up