dependencies {

              implementation 'com.google.android.gms:play-services-maps:17.0.0'
             }

     <meta-data
         android:name="com.google.android.maps.v2.API_KEY"
        android:value="AIzaSyAPD2Zrr3aCGnPcTkYQqViAtF3jFtWn6us"/> //replace your api key 

  <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

import android.Manifest
import android.app.AlertDialog
import android.content.pm.PackageManager
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import androidx.databinding.DataBindingUtil
import com.example.mymap.MainActivity
import com.example.mymap.databinding.ActivityMainBinding
import com.google.android.gms.maps.CameraUpdateFactory
import com.google.android.gms.maps.GoogleMap
import com.google.android.gms.maps.OnMapReadyCallback
import com.google.android.gms.maps.model.LatLng
import com.google.android.gms.maps.model.MarkerOptions

class MainActivity : AppCompatActivity(), OnMapReadyCallback {
var binding: ActivityMainBinding? = null
var mGoogleMap: GoogleMap? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
binding?.mapView?.onCreate(savedInstanceState)
// checkLocationPermission();
binding?.mapView?.getMapAsync(this)
}

override fun onMapReady(googleMap: GoogleMap) {
// mGoogleMap = googleMap;


// Creating a marker
val markerOptions = MarkerOptions()
// Setting the position for the marker
markerOptions.position(LatLng(26.9124, 75.7873))
// Animating to the marker position
googleMap.animateCamera(CameraUpdateFactory.newLatLng(LatLng(26.9124, 75.7873)))
// Placing a marker on the touched position
googleMap.addMarker(markerOptions)
}


public override fun onResume() {
binding!!.mapView.onResume()
super.onResume()
}

public override fun onPause() {
super.onPause()
binding!!.mapView.onPause()
}

public override fun onDestroy() {
super.onDestroy()
binding!!.mapView.onDestroy()
}

override fun onLowMemory() {
super.onLowMemory()
binding!!.mapView.onLowMemory()
}

}

<?xml version="1.0" encoding="utf-8"?>
<layout>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<com.google.android.gms.maps.MapView
android:id="@+id/mapView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>
</layout>

dependencies:
 
  google_maps_flutter: ^1.0.3

    <meta-data android:name="com.google.android.geo.API_KEY"
            android:value="Your-api-key"/>

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {

  GoogleMapController mapController;

  final LatLng _center = const LatLng(26.9124, 75.7873);

  void _onMapCreated(GoogleMapController controller) {
    mapController = controller;
  }




  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return  Scaffold(
        appBar: AppBar(
          title: Text('Maps Sample App'),
          backgroundColor: Colors.green[700],
        ),
        body: GoogleMap(
          onMapCreated: _onMapCreated,
          initialCameraPosition: CameraPosition(
            target: _center,
            zoom: 15.0,
          ),
        ),
      );

  }
}