CODEWITHSUNDEEP
javaandroidbluetoothbluetooth-lowenergy
MHSN
MHSN

Reputation: 29

Force stopping LE Scan while BT Adapter is OFF thows java.lang.IllegalStateException (IN NEXUS 5 and Android 6)

I am facing this error while disabling Bluetooth. Googled it but did not find solution. Here is my broadcast receiver which invokes when bluetooth state is changed. 

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            Log.e(LOG_TAG, "Broadcast receiver - onReceive");
            if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
                h.removeCallbacks(runnable);
                final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
                switch (state) {
                    case BluetoothAdapter.STATE_OFF:
                        Log.i(LOG_TAG, "***** BLE-Bluetooth is disabled");
                        Toast.makeText(getApplicationContext(), "Bluetooth is disabled", Toast.LENGTH_LONG).show();
                        Log.i(TAG, "***** mBeaconScanner "+ mBeaconScanner);
                        if(null != mBeaconScanner)
                            mBeaconScanner.scanLeDevice(false);
                        break;
                    case BluetoothAdapter.STATE_ON:
                        Log.i(LOG_TAG, "***** BLE-Bluetooth is enabled");
                        Toast.makeText(getApplicationContext(), "Bluetooth is enabled", Toast.LENGTH_LONG).show();
                        if(null != mBeaconScanner)
                            mBeaconScanner.scanLeDevice(true);
                        break;
                }
            }
        }
    };

In the above code I am trying to stop ble scanning while disabling the Bluetooth. In the above code method "mBeaconScanner.scanLeDevice(false);" redirects to :

Log.i(TAG, "***** Stopping BLE Scan for Android version " + Build.VERSION.SDK_INT);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

                if (bluetoothLeScanner != null)
                {

                        bluetoothLeScanner.stopScan(mScanCallback);

                }
            } else {
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
            }

In the above snippet I am getting Exception when calling bluetoothLeScanner.stopScan(mScanCallback) method.

NOTE: this issue is not reproducible in all the devices but nexus and its not very frequently reproducible as well for me.

Please suggest me if there is any solution for this.. Thanks in advance

Upvotes: 0

Views: 666

Answers (1)

Zakir
Zakir

Reputation: 2382

The only solution I can suggest here is comment this code:- 

//mBeaconScanner.scanLeDevice(false);

The way BLE scan works is pretty complicated at the radio level. There are tons of factors (like power, efficiency etc..) that are taken into consideration while arriving at the right scan window sleep time etc..
For you in this particular case when the BT adapter itself is turned OFF, trying to stop scan is an invalid operation as far as the radio is concerned. Am glad that Android FW throws this exception !! Just get rid of this code and may be do some internal app specific state transition (if you have to) or else just log and be done in case BluetoothAdapter.STATE_OFF:

Upvotes: 1

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