Getting null pointer when using getMapAsync

Question

I am trying to create an app with a simple UI. It consists of one activity and which comprises of 2 buttons, a textview and a google maps fragment which fills up half the screen. I've created the layout using drag and drop elements provided from Android Studio.

The problem is that when I try to run it, I get the following error: jjava.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.MapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference

This is my activity:

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback{

RequestQueue requestQueue;
Button serviceButton;
TextView textViewService;
SensorResponse responseJson;
private GoogleMap googleMap;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestQueue = Volley.newRequestQueue(this);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    MapFragment mapFragment = (MapFragment) getFragmentManager().findFragmentById(R.id.mapView2);
    mapFragment.getMapAsync(this);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    textViewService = findViewById(R.id.textViewServiceOutput);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });
}

@Override
public void onMapReady(GoogleMap map) {

    googleMap = map;

    setUpMap();

}
public void setUpMap(){

    googleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
    //googleMap.setMyLocationEnabled(true);
    googleMap.setTrafficEnabled(true);
    googleMap.setIndoorEnabled(true);
    googleMap.setBuildingsEnabled(true);
    googleMap.getUiSettings().setZoomControlsEnabled(true);
}}

I've googled the error and have tried the solutions that I came across such as trying to SupportMapFragment but it still does not work.

Following is my layout file:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.tarikh.myapplication.MainActivity"
tools:showIn="@layout/activity_main">

<Button
    android:id="@+id/button3"
    android:layout_width="wrap_content"
    android:layout_height="47dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:onClick="callTheService"
    android:text="Call Service"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/mapButton" />

<TextView
    android:id="@+id/textViewServiceOutput"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginEnd="128dp"
    android:layout_marginRight="128dp"
    android:layout_marginTop="16dp"
    android:text="Parking Bay Checker"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/mapButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:onClick="callTheMap"
    android:text="Call Map"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textViewServiceOutput" />

<com.google.android.gms.maps.MapView
    android:id="@+id/mapView2"
    android:layout_width="match_parent"
    android:layout_height="244dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="44dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/button3" />

</android.support.constraint.ConstraintLayout>

EDIT: Thanks for the input, after a bit a tweaking, I've managed to get it working. I replaced the map on my activity layout with the following:

    <fragment
    android:id="@+id/mapFrag"
    class="com.google.android.gms.maps.MapFragment"
    android:layout_width="match_parent"
    android:layout_height="329dp"
    android:layout_marginTop="164dp"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

Can you update layout file? – Ramesh sambu Dec 20 '17 at 19:06 — Ramesh sambu, Dec 20 '17 at 19:06
@R2R updated the question with my layout file – dfqupwndguerrillamailde Dec 20 '17 at 19:09 — dfqupwndguerrillamailde, Dec 20 '17 at 19:09

score 1 · Answer 1 · answered Dec 20 '17 at 19:10

1

Below statement will return null, as you have not added MapFragment in activity, you have added MapView

(MapFragment) getFragmentManager().findFragmentById(R.id.mapView2)

answered Dec 20 '17 at 19:10

Akhil

6,667
4
31
61

score 1 · Answer 2 · answered Dec 20 '17 at 19:17

1

In layout try to use MapFragment.Your Assigning MapView to MapFragment that is why null cause

    <fragment 
    android:id="@+id/mapView2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.google.android.gms.maps.SupportMapFragment"
    />

Here you can see where we have to use MapView and MapFragment

https://stackoverflow.com/a/34626302/3505534

answered Dec 20 '17 at 19:17

Ramesh sambu

3,577
2
24
39

Thanks for the suggestion, it worked. Is it compulsory to make a fragment reside inside a container (e.g. relative layout) or can a fragment exist on its on with no containers? – dfqupwndguerrillamailde Dec 20 '17 at 19:24

Getting null pointer when using getMapAsync

2 Answers2