Fix scan precondition verifier for Android 10

[dariuszseweryn]

Summary

On Android 10 scan needs ACCESS_FINE_LOCATION permission.

Library version

1.10.3

Preconditions

Android 10 mobile phone to run the test

Steps to reproduce actual result

1. Use an app with ACCESS_COARSE_LOCATION

2. Try to run a scan

3. Observe result

Actual result

Scan seems to be started correctly but a log is shown:

E/BluetoothUtils: Permission denial: Need ACCESS_FINE_LOCATION permission to get scan results

Expected result

A BleScanException is emitted with a desirable error code LOCATION_PERMISSION_MISSING or FINE_LOCATION_PERMISSION_MISSING (TBD)

Minimum code snippet reproducing the issue

        val scanSettings = ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
            .build()

        val scanFilter = ScanFilter.Builder()
            // add custom filters if needed
            .build()

        rxBleClient.scanBleDevices(scanSettings, scanFilter).subscribe()

Logs from the application running with settings:

RxBleClient.updateLogOptions(new LogOptions.Builder()
        .setLogLevel(LogConstants.DEBUG)
        .setMacAddressLogSetting(LogConstants.MAC_ADDRESS_FULL)
        .setUuidsLogSetting(LogConstants.UUIDS_FULL)
        .setShouldLogAttributeValues(true)
        .build()
);

2019-10-28 17:29:28.364 8318-8357/com.polidea.rxandroidble.sample I/RxBle#ClientOperationQueue: RUNNING  ScanOperationApi21{ANY_MUST_MATCH -> nativeFilters=[BluetoothLeScanFilter [mDeviceName=null, MAC=null, mUuid=null, mUuidMask=null, mServiceDataUuid=null, mServiceData=null, mServiceDataMask=null, mManufacturerId=-1, mManufacturerData=null, mManufacturerDataMask=null]]}
2019-10-28 17:29:28.365 8318-8380/com.polidea.rxandroidble.sample I/RxBle#QueueOperation: Scan operation is requested to start.
2019-10-28 17:29:28.368 8318-8380/com.polidea.rxandroidble.sample D/BluetoothAdapter: isLeEnabled(): ON
2019-10-28 17:29:28.374 6276-6323/? I/bt_stack: [INFO:gatt_api.cc(946)] GATT_Register 4f95b434-3363-7845-06bf-01ea4105e510
2019-10-28 17:29:28.374 6276-6323/? I/bt_stack: [INFO:gatt_api.cc(966)] allocated gatt_if=7
2019-10-28 17:29:28.375 8318-8345/com.polidea.rxandroidble.sample D/BluetoothLeScanner: onScannerRegistered() - status=0 scannerId=7 mScannerId=0
2019-10-28 17:29:28.380 6276-6294/? E/BluetoothUtils: Permission denial: Need ACCESS_FINE_LOCATION permission to get scan results

[Steppschuh]

This should probably be mentioned in the Permissions section of the readme.

[dariuszseweryn]

How would you see it?

[Steppschuh]

I just would give a heads up to users that they need to request the ACCESS_FINE_LOCATION permission on Android 10+. From the current wording one could think that ACCESS_COARSE_LOCATION would be sufficient.

[dariuszseweryn]

Should be better now