App crashes when Bluetooth is off

Question

I have my Android app with BLE. I turn off the BLE and kill the app in RAM. I get force close. When I see the log it says -

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeScanner.stopScan(android.bluetooth.le.ScanCallback)' on a null object reference
                                                                                  at com.hi.ble.utils.BLEScanner.stopScan(Unknown Source)

When I check my code, It is like this -

public void stopScan() {

        if(bluetoothAdapter == null) {
            return;
        }

        if (Build.VERSION.SDK_INT < 21) {
            Log.i(TAG, "Stopping BLE scan (SDK < 21)");
            bluetoothAdapter.stopLeScan(this);

        } else {
            Log.i(TAG, "Stopping BLE scan (SDK >= 21)");
                mLEScanner.stopScan(mScanCallback);
        }
        runnerRunning = false;
        thread = null;

    }

How do I over come this problem?

do you have notified user to turn on bluetooth? If not then do it and once you get result of it, start your function — Lalit Jadav, Jan 06 '17 at 13:41
Yes...But what if still user doesnt want to turn on bluetooth and kills app in RAM — , Jan 06 '17 at 13:41
mLEScanner is null. http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it — krossovochkin, Jan 06 '17 at 13:41
@krossovochkin - i know what is NPE. I dont want an exception in my code — , Jan 06 '17 at 13:44

score 0 · Answer 1 · answered Jan 06 '17 at 13:46

Try this

public void stopScan() {


    if (Build.VERSION.SDK_INT < 21) {
        Log.i(TAG, "Stopping BLE scan (SDK < 21)");
        if(bluetoothAdapter != null) bluetoothAdapter.stopLeScan(this);

    } else {
        Log.i(TAG, "Stopping BLE scan (SDK >= 21)");
         if(mLEScanner!= null) mLEScanner.stopScan(mScanCallback);
    }
    runnerRunning = false;
    thread = null;

}

App crashes when Bluetooth is off

1 Answers1