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androidbluetooth-lowenergyandroid-12

BLE scanner on Android 12 not emit devices in Foreground service after phone reboot

I have Android 10 and Android 12 phones. BLE scanner works fine after rebooting the first one, but doesn't work on the second one.

App has all required permissions requested in runtime:

    <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30"/>
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" android:maxSdkVersion="23"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

GPS and Bluetooth are enabled on the phone.

After rebooting, Foreground service is started from the broadcast receiver (Intent.ACTION_BOOT_COMPLETED).

This service then starts the BLE scanner with the scan filter:

bleAdapter.bluetoothLeScanner.startScan(filters, settings, callback)

It's successfully registered in system (BluetoothLeScanner: onScannerRegistered() - status=0 scannerId=7 mScannerId=0), but there are no devices in the scanner callback on Android 12.

What is the reason and how to solve this problem?

Solution

  • BLE scanner in service started after phone reboot requires android.permission.ACCESS_BACKGROUND_LOCATION permission at runtime - Allow all the time in location permission settings page (not Allow only while using the app). It's not enough to only put it in AndroidManifest.

    More about permission here: https://developer.android.com/training/location/permissions#request-background-location