Attempt to invoke virtual method 'void com.google.android.gms.maps.GoogleMap.setOnMapLongClickListener' on a null object reference

android android-maps
Prabu Guna picture Prabu Guna · Dec 29, 2015 · Viewed 11.3k times · Source

When i long press the map it should add marker into the place. But its not working. My app crashes when i m trying to run this. Please help me out

Here's my code

package inandroid.jeetna.memorableplaces;


import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.MenuItem;

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.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends AppCompatActivity implements OnMapReadyCallback,GoogleMap.OnMapLongClickListener {

    private GoogleMap mMap;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        mMap.setOnMapLongClickListener(this);

        android.support.v7.app.ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);


        Intent i = getIntent();
        Log.i("locationInfo", Integer.toString(i.getIntExtra("locationinfo", -1)));
    }



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

        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-34, 151);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                this.finish();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }


    @Override
    public void onMapLongClick(LatLng point) {
        mMap.addMarker(new MarkerOptions()
                .position(point)
                .title("You are here")
                .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
    }

}

This is error message i m getting

12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: FATAL EXCEPTION: main 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: Process: inandroid.jeetna.memorableplaces, PID: 7519 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{inandroid.jeetna.memorableplaces/inandroid.jeetna.memorableplaces.MapsActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.GoogleMap.setOnMapLongClickListener(com.google.android.gms.maps.GoogleMap$OnMapLongClickListener)' on a null object reference 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.access$800(ActivityThread.java:144) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.os.Looper.loop(Looper.java:135) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5221) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:372) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.GoogleMap.setOnMapLongClickListener(com.google.android.gms.maps.GoogleMap$OnMapLongClickListener)' on a null object reference 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at inandroid.jeetna.memorableplaces.MapsActivity.onCreate(MapsActivity.java:33) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.Activity.performCreate(Activity.java:5937) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251) 12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.access$800(ActivityThread.java:144)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.os.Looper.loop(Looper.java:135)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5221)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:372)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)  12-29 12:42:07.118 7519-7519/inandroid.jeetna.memorableplaces E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

Answer

Pankaj picture Pankaj · Dec 29, 2015

In your Long click method do something like below code

public void onMapLongClick(LatLng point) {
       if(mMap != null){
        mMap.addMarker(new MarkerOptions()
                .position(point)
                .title("You are here")
                .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
      }
 }

And move the line mMap.setOnMapLongClickListener(this); from onCreate() method to onMapReady() method as follows:

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

        //your code
    }

This is because your mMap is null until it assigned the googleMap object from onMapReady() method

Related questions

Google Maps Android API v2 Authorization failure

My steps: got SHA1 code from debug.keystore create app in google apis console enabled google map api v2 input SHA1;my.package.name get API key created AndroidManifest file: <permission android:name="my.package.name.permission.MAPS_RECEIVE" …

Read More
Duplicate ID, tag null, or parent id with another fragment for com.google.android.gms.maps.MapFragment

I have an application with three tabs. Each tab has its own layout .xml file. The main.xml has its own map fragment. It's the one that shows up when the application first launches. Everything works fine except for when …

Read More
How do I show a marker in Maps launched by geo URI Intent?

I have a application where I want to show different locations (one at the time, picked by user input) by launching Google Maps with their specific geo coordinates. I'm currently using this (with real lat. and long. values of course): …

Read More