get last location()

package com.example.maps

import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.location.Geocoder
import android.location.LocationManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.Looper
import android.util.Log
import android.widget.Toast
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import com.google.android.gms.location.*
import com.google.android.gms.maps.model.LatLng
import kotlinx.android.synthetic.main.activity_main.*
import java.util.*

class MainActivity : AppCompatActivity() {

    // variable that we need
    lateinit var fusedLocationProviderClient: FusedLocationProviderClient
    lateinit var locationRequest: LocationRequest

    // just a unique number
    var PERMISSION_ID = 1000

    var Latitude: Double = 0.0
    var Longitude: Double = 0.0

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

        // initial lateinit var
        fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this)
        buttonGetLocation.setOnClickListener{
            getLastLoacation()
        }

        buttonMaps.setOnClickListener{
            val intent = Intent(this, MapsActivity::class.java)
            intent.putExtra("LATITUDE", Latitude)
            intent.putExtra("LONGITUDE", Longitude)
            startActivity(intent)

        }
    }

    // get last location
    private fun getLastLoacation() {
        // check permission
        if (checkPermission()) {
            // check location services is enable
            if (isLocationEnable()) {
                // get the location
                fusedLocationProviderClient.lastLocation.addOnCompleteListener { task ->
                    var location = task.result
                    if (location == null) {
                        getNewLocation()
                    } else {
                        Latitude = location.latitude
                        Longitude = location.longitude
                        textViewLocation.text =
                            "Your Current Cordinate Are " +
                                    "\nLat: $Latitude" +
                                    "\nLong: $Longitude" +
                                    "\nCountryName: ${getCountryName(location.latitude, location.longitude)}" +
                                    "\nCityName: ${getCityName(location.latitude, location.longitude)}"
                    }
                }
            } else {
                Toast.makeText(this, "Please Enable Your Location Services", Toast.LENGTH_SHORT)
                    .show()
            }
        } else {
            requestPermission()
        }
    }

    // get new location
    private fun getNewLocation() {
        locationRequest = LocationRequest()
        locationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY
        locationRequest.interval = 0
        locationRequest.fastestInterval = 0
        locationRequest.numUpdates = 2
        checkPermission()
        fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallBack, Looper.myLooper())
    }

    // get city name
    private fun getCityName(lat: Double, long: Double): String{
        var cityName = ""
        var geoCoder = Geocoder(this, Locale.getDefault())
        var address = geoCoder.getFromLocation(lat, long, 1)
        cityName = address.get(0).locality
        return cityName
    }

    private fun getCountryName(lat: Double, long: Double): String{
        var countryName = ""
        var geoCoder = Geocoder(this, Locale.getDefault())
        var address = geoCoder.getFromLocation(lat, long, 1)
        countryName = address.get(0).countryName
        return countryName
    }
    private val locationCallBack = object : LocationCallback() {
        override fun onLocationResult(p0: LocationResult) {
            var lastLocation = p0.lastLocation
            Latitude = lastLocation.latitude
            Longitude = lastLocation.longitude
            textViewLocation.text =
                "Your Current Cordinate Are " +
                        "\nLat: $Latitude" +
                        "\nLong: $Longitude" +
                        "\nCountryName: ${getCountryName(Latitude, Longitude)}" +
                        "\nCityName: ${getCityName(Latitude, Longitude)}"
        }
    }

    // check uses permission
    private fun checkPermission(): Boolean {
        if (
            ContextCompat.checkSelfPermission(
                this,
                android.Manifest.permission.ACCESS_FINE_LOCATION
            ) == PackageManager.PERMISSION_GRANTED ||
            ContextCompat.checkSelfPermission(
                this,
                android.Manifest.permission.ACCESS_COARSE_LOCATION
            ) == PackageManager.PERMISSION_GRANTED
        ) {
            return true
        }
        return false
    }

    // request get user permission
    private fun requestPermission() {
        ActivityCompat.requestPermissions(
            this,
            arrayOf(
                android.Manifest.permission.ACCESS_FINE_LOCATION,
                android.Manifest.permission.ACCESS_COARSE_LOCATION
            ),
            PERMISSION_ID
        )
    }

    // check if location services is enable
    private fun isLocationEnable(): Boolean {
        var locationManager = getSystemService(Context.LOCATION_SERVICE) as LocationManager
        return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
                locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        // super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        // built in function that check permission result
        if (requestCode == PERMISSION_ID) {
            if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Log.d("Debug: ", "You have he permission")
            }
        }
    }
}