MyLocationDemoActivity.kt

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.example.kotlindemos

import android.Manifest
import android.annotation.SuppressLint
import android.content.pm.PackageManager
import android.location.Location
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat.OnRequestPermissionsResultCallback
import androidx.core.content.ContextCompat
import com.example.kotlindemos.PermissionUtils.PermissionDeniedDialog.Companion.newInstance
import com.example.kotlindemos.PermissionUtils.isPermissionGranted
import com.example.kotlindemos.PermissionUtils.requestPermission
import com.google.android.gms.maps.GoogleMap
import com.google.android.gms.maps.GoogleMap.OnMyLocationButtonClickListener
import com.google.android.gms.maps.GoogleMap.OnMyLocationClickListener
import com.google.android.gms.maps.OnMapReadyCallback
import com.google.android.gms.maps.SupportMapFragment

/**
 * This demo shows how GMS Location can be used to check for changes to the users location.  The
 * "My Location" button uses GMS Location to set the blue dot representing the users location.
 * Permission for [Manifest.permission.ACCESS_FINE_LOCATION] is requested at run
 * time. If the permission has not been granted, the Activity is finished with an error message.
 */
class MyLocationDemoActivity : AppCompatActivity(), OnMyLocationButtonClickListener,
    OnMyLocationClickListener, OnMapReadyCallback, OnRequestPermissionsResultCallback {
    /**
     * Flag indicating whether a requested permission has been denied after returning in
     * [.onRequestPermissionsResult].
     */
    private var permissionDenied = false
    private lateinit var map: GoogleMap
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.my_location_demo)
        val mapFragment = supportFragmentManager.findFragmentById(R.id.map) as SupportMapFragment?
        mapFragment?.getMapAsync(this)
    }

    override fun onMapReady(googleMap: GoogleMap) {
        map = googleMap
        googleMap.setOnMyLocationButtonClickListener(this)
        googleMap.setOnMyLocationClickListener(this)
        enableMyLocation()
    }

    /**
     * Enables the My Location layer if the fine location permission has been granted.
     */
    @SuppressLint("MissingPermission")
    private fun enableMyLocation() {
        if (!::map.isInitialized) return
        // [START maps_check_location_permission]
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            == PackageManager.PERMISSION_GRANTED) {
            map.isMyLocationEnabled = true
        } else {
            // Permission to access the location is missing. Show rationale and request permission
            requestPermission(this, LOCATION_PERMISSION_REQUEST_CODE,
                Manifest.permission.ACCESS_FINE_LOCATION, true
            )
        }
        // [END maps_check_location_permission]
    }

    override fun onMyLocationButtonClick(): Boolean {
        Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show()
        // Return false so that we don't consume the event and the default behavior still occurs
        // (the camera animates to the user's current position).
        return false
    }

    override fun onMyLocationClick(location: Location) {
        Toast.makeText(this, "Current location:\n$location", Toast.LENGTH_LONG).show()
    }

    // [START maps_check_location_permission_result]
    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
        if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) {
          super.onRequestPermissionsResult(requestCode, permissions, grantResults)
          return
        }
        if (isPermissionGranted(permissions, grantResults, Manifest.permission.ACCESS_FINE_LOCATION)) {
            // Enable the my location layer if the permission has been granted.
            enableMyLocation()
        } else {
            // Permission was denied. Display an error message
            // [START_EXCLUDE]
            // Display the missing permission error dialog when the fragments resume.
            permissionDenied = true
            // [END_EXCLUDE]
        }
    }

    // [END maps_check_location_permission_result]
    override fun onResumeFragments() {
        super.onResumeFragments()
        if (permissionDenied) {
            // Permission was not granted, display error dialog.
            showMissingPermissionError()
            permissionDenied = false
        }
    }

    /**
     * Displays a dialog with error message explaining that the location permission is missing.
     */
    private fun showMissingPermissionError() {
        newInstance(true).show(supportFragmentManager, "dialog")
    }

    companion object {
        /**
         * Request code for location permission request.
         *
         * @see .onRequestPermissionsResult
         */
        private const val LOCATION_PERMISSION_REQUEST_CODE = 1
    }
}