import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
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.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {

    private static final int LOCATION_PERMISSION_REQUEST_CODE = 1;

    private GoogleMap mMap;
    private FusedLocationProviderClient fusedLocationClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        // Check if location permission is granted
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mMap.setMyLocationEnabled(true);
            getCurrentLocation();
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    LOCATION_PERMISSION_REQUEST_CODE);
        }
    }

    private void getCurrentLocation() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            fusedLocationClient.getLastLocation()
                    .addOnSuccessListener(this, location -> {
                        if (location != null) {
                            LatLng currentLocation = new LatLng(location.getLatitude(), location.getLongitude());
                            mMap.addMarker(new MarkerOptions().position(currentLocation).title("Current Location"));
                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, 15f));
                        }
                    });
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == LOCATION_PERMISSION_REQUEST_CODE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                onMapReady(mMap);
            } else {
                Toast.makeText(this, "Location permission denied", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

Kotlin online compiler

Write, Run & Share Kotlin code online using OneCompiler’s Kotlin online compiler for free. It’s a modern and fast online playground for Kotlin, supporting the latest version and ideal for learning, experimenting, and sharing code instantly.

About Kotlin

Kotlin is a statically typed, modern programming language developed by JetBrains. It runs on the JVM and is fully interoperable with Java. Kotlin is concise, expressive, and safe, and it’s officially supported by Google for Android app development.

Sample Code

The following is a simple Kotlin program that prints a greeting:

fun main() {
    println("Hello, OneCompiler!")
}

Taking inputs (stdin)

OneCompiler’s Kotlin editor supports stdin. You can provide input using the I/O tab. Here's a sample program that reads a line of input and prints a greeting:

fun main() {
    print("Enter your name: ")
    val name = readLine()
    println("Hello, $name")
}

Syntax Basics

Variables

val name: String = "OneCompiler"  // Immutable
var age: Int = 25                 // Mutable

Kotlin supports type inference, so explicit types are optional:

val city = "Hyderabad"
var count = 10

Conditionals

val score = 85
if (score >= 50) {
    println("Pass")
} else {
    println("Fail")
}

Loops

For loop

for (i in 1..5) {
    println(i)
}

While loop

var i = 1
while (i <= 5) {
    println(i)
    i++
}

Do-While loop

var j = 1
do {
    println(j)
    j++
} while (j <= 5)

Functions

fun add(a: Int, b: Int): Int {
    return a + b
}

fun greet(name: String) = "Hello, $name"

Collections

val items = listOf("apple", "banana", "cherry")
for (item in items) {
    println(item)
}

This guide provides a quick reference to Kotlin programming syntax and features. Start coding in Kotlin using OneCompiler’s Kotlin online compiler today!