I get following error while trying to run the code for getting a location:
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.map, PID: 19412 java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.location.LocationManager.isProviderEnabled(java.lang.String)' on a null object reference at com.example.map.MainActivity$1.onClick(MainActivity.java:39)
Here's my code : mainactivity.java
package com.example.map;
import android.Manifest;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationManager;
import android.provider.Settings;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
public class MainActivity extends AppCompatActivity {
private static final int REQUEST_LOCATION = 1;
Button btnGetLocation;
TextView showLocation;
LocationManager locationManager;
String latitude, longitude;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions( this,
new String[] {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
showLocation = findViewById(R.id.showLocation);
btnGetLocation = findViewById(R.id.btnGetLocation);
btnGetLocation.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
LocationManager nManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
OnGPS();
} else {
getLocation();
}
}
});
}
private void OnGPS() {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Enable GPS").setCancelable(false).setPositiveButton("Yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
startActivity(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
}).setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
final AlertDialog alertDialog = builder.create();
alertDialog.show();
}
private void getLocation() {
if (ActivityCompat.checkSelfPermission(
MainActivity.this,Manifest.permission.ACCESS_FINE_LOCATION) !=
PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) !=
PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
} else {
Location locationGPS = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (locationGPS != null) {
double lat = locationGPS.getLatitude();
double longi = locationGPS.getLongitude();
latitude = String.valueOf(lat);
longitude = String.valueOf(longi);
showLocation.setText(String.format("%s\n%s%s\n%s%s", getString(R.string.your_location), getString(R.string.latitude), latitude, getString(R.string.longitude), longitude));
} else {
Toast.makeText(this, "Unable to find location.", Toast.LENGTH_SHORT).show();
}
}
}
}
> activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center"
tools:context=".MainActivity">
<TextView
android:id="@+id/showLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="Location"
android:textSize="24sp" />
<Button
android:id="@+id/btnGetLocation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Get Location" />
</LinearLayout>
