Android BLE ScanResult List processing

Question

I'm new to Android and Kotlin and I get stuck at a point in listing the discovered BLE devices. When a BLE Device was found the onScanResult callback gets fired and the data of the found BLE device is available as class ScanResult.

To list all available BLE devices I have an mLeDevices: ArrayList<ScanResult> = ArrayList() where the found device gets added if it's not already in the list.

private val bleCallback: ScanCallback = object :ScanCallback() {
    override fun onScanResult(callbackType: Int, result: ScanResult) {
        super.onScanResult(callbackType, result)

        if (!mLeDevices.contains(result)) {
            mLeDevices.add(result)
        }
    }
}

But with this code every device gets added in the List multiple times since ScanResult also contains the RSSI Value which is varying. I think I have to check if mLeDevices contains result.device.address. If yes just update the rssi value, if not add the new device to the list. But i don't know how to implement that approach in the best way. Is there a way in Kotlin to check if an ArrayList of a class contains an element which contains an attribute? Or is there another solution for my problem?

Answer 1

You can use none function that takes a lambda. You can then the condition on the unique attribute.

if (mLeDevices.none { it.BSSID == result.BSSID }) {
   mLeDevices.add(result)
}