[Android] WiFiのアクセスポイントまでの距離を計測する

はじめに
おわりに

はじめに

検証用に社長に作ってって言われたから、雑に作った。本当にいろいろ雑だからいろいろと気にしちゃいけない。あと、見せちゃいけなさそうな部分は意図的にコード消してる。

流れ的にはWiFi情報を取得してWiFI情報の電波強度？をモニョモニョ計算するって感じ。流れというかそのままだけどｗ

WiFi情報を取得するサービスを作成

WifiScanService.kt

//
const val ACTION_WIFI_SCAN_ACTION= "WIFI.SCAN.ACTION"
const val EXTRA_WIFI_SCAN= "extra_wifi_scan"

class WifiScanService : Service() {


    private val handler: Handler = Handler()
    private lateinit var runnable: Runnable

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {

        runnable = Runnable{

           val wm = applicationContext.getSystemService(Context.WIFI_SERVICE) as? WifiManager
            wm?.startScan()

            val scanResults = wm?.scanResults?.filter{
               true
            }
           val broadcastIntent = Intent(ACTION_WIFI_SCAN_ACTION)
            broadcastIntent.putParcelableArrayListExtra(EXTRA_WIFI_SCAN, ArrayList(scanResults))

            LocalBroadcastManager.getInstance(this).sendBroadcast(broadcastIntent)

            handler.postDelayed(runnable, 5000)
        }
       handler.post(runnable)
        return Service.START_NOT_STICKY
   }

    override fun onBind(intent: Intent?): IBinder? {
        // バインドさせない
        return null
    }
    
    override fun onDestroy() {
        super.onDestroy()
        handler.removeCallbacks(runnable)
    }

}

サービスから情報を受け取るレシーバーを作成

WifiScanReceiver.kt

//
class WifiScanReceiver : BroadcastReceiver() {

    var listener: OnWifiScanListener? = null

    interface OnWifiScanListener {
        fun onWifiScan(scanResults: List<ScanResult>?)
    }

    override fun onReceive(context: Context, intent: Intent) {
        val scanResults = intent.getParcelableArrayListExtra<ScanResult>(EXTRA_WIFI_SCAN)
        listener?.onWifiScan(scanResults)

    }
}

WiFi情報とアクセスポイントまでの距離を持ってるクラス作成

WiFiApData.kt

//
class WifiApData(val scanResult: ScanResult) {
    var distance: Double = 0.0
}

距離を計算するクラス作成

//
class WifiApDistanceCalculatorModel {

   fun getWifiApDates(scanResults: List<ScanResult>?): List<WifiApData> {

        val wifiApDates: MutableList<WifiApData> = mutableListOf()
        scanResults?.forEach{
           val wifiApData = WifiApData(it)
            wifiApData.distance = calculateDistance(it.level.toDouble(), it.frequency.toDouble())
            wifiApDates.add(wifiApData)
        }

       return wifiApDates.sortedBy{ it.distance }
   }

    private fun calculateDistance(levelInDb: Double, freqInMHz: Double): Double {
        val exp = (27.55 - 20 * Math.log10(freqInMHz) + Math.abs(levelInDb)) / 20.0
        return Math.pow(10.0, exp)
    }
}

Activity

//
@RuntimePermissions
class MainActivity : AppCompatActivity(), WifiScanReceiver.OnWifiScanListener {

    protected val wifiApDistanceCalculatorModel: WifiApDistanceCalculatorModel = WifiApDistanceCalculatorModel()
    private lateinit var wifiScanReceiver: WifiScanReceiver

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        wifiScanReceiver = WifiScanReceiver()
        wifiScanReceiver.listener = this

        startWiFiScanServiceWithPermissionCheck()
    }

    @NeedsPermission(android.Manifest.permission.ACCESS_COARSE_LOCATION)
    fun startWiFiScanService() {
        startService(Intent(this, WifiScanService::class.java))
    }

    @OnPermissionDenied(android.Manifest.permission.ACCESS_COARSE_LOCATION)
    fun showDeniedForWiFiScanService() {
        Toast.makeText(this, "非許可", Toast.LENGTH_SHORT).show()
    }

    @OnNeverAskAgain(android.Manifest.permission.ACCESS_COARSE_LOCATION)
    fun showNeverAskWiFiScanService() {
        Toast.makeText(this, "今後表示しない", Toast.LENGTH_SHORT).show()
    }

    override fun onResume() {
        super.onResume()
        LocalBroadcastManager.getInstance(this)
            .registerReceiver(wifiScanReceiver, IntentFilter(ACTION_WIFI_SCAN_ACTION))

    }

    override fun onPause() {
        super.onPause()
        LocalBroadcastManager.getInstance(this).unregisterReceiver(wifiScanReceiver)

    }

    override fun onDestroy() {
        super.onDestroy()
        stopService(Intent(this, WifiScanService::class.java))
    }

    override fun onWifiScan(scanResults: List<ScanResult>?) {
        val list = wifiApDistanceCalculatorModel.getWifiApDates(scanResults)
　　　　// いろいろモニョモニョする。
        
   }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        onRequestPermissionsResult(requestCode, grantResults)

    }
}