I am trying to scan devices using BloothLeScanner.startScan() but I am not able to find any

Question

This is the error i am getting:

Attempt to invoke virtual method 'void android.bluetooth.le.BluetoothLeScanner.startScan(android.bluetooth.le.ScanCallback)' on a null object reference

I tried adding coarse_location permissions both in manifest and at run time but it didn't work and also turned on location. Can someone help me in this.

I use this to scan Low energy devices.

mBluetoothLeScanner.startScan(mLeScanCallback);

This is my scancallback.

final ScanCallback mLeScanCallback = new ScanCallback() {
            @Override
            public void onScanResult(int callbackType, ScanResult result) {
                final int new_rssi = result.getRssi();
                addDevice(result, new_rssi);
                super.onScanResult(callbackType, result);
            }

Duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Phantômaxx, Feb 20 '19 at 13:58
My problem is not null point error. My problem is that I am not getting any results from my scancallback. — ravindra gollapudi, Feb 20 '19 at 14:17
`... but i am getting an null pointer exception error` Your main worry is actually to fix your **NPE**. — Phantômaxx, Feb 20 '19 at 14:18
Even though I fix my NPE using try catch or passing some random value, my main worry is that I am not able to find any BLE devices in my scan. — ravindra gollapudi, Feb 21 '19 at 06:20
show code for how you get the `mBluetoothLeScanner` , probably you fetch the scanner with wrong method and it is null. — Maksim Novikov, Feb 21 '19 at 07:27
private BluetoothLeScanner mBluetoothLeScanner; This is line I used to get my scanner. — ravindra gollapudi, Feb 21 '19 at 09:50

score 0 · Accepted Answer · answered Feb 22 '19 at 00:51

2 possibilities come to my mind:

Bluetooth is disabled - this would cause NPE when trying to start a BLE scan
Check if you're Location is enabled. Go to Settings > Location. BLE requires device's location to work, if you start a BLE scan when Location is disabled you won't receive any results

I am trying to scan devices using BloothLeScanner.startScan() but I am not able to find any

1 Answers1