android SupportMapFragment : java.lang.NullPointerException

Question

I am getting a java.lang.NullPointerException on the line map.setOnMyLocationChangeListener(myLocationChangeListener);. Strangely, this exception arises while running it some devices while in some it doesn't. How do I solve this?

public class MyMap extends ActionBarActivity implements
    RoutingListener, OnMapReadyCallback,
     SensorEventListener {

// private GoogleApiClient mGoogleApiClient;
protected GoogleMap map;

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

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

    if (mapFragment == null) {
        mapFragment = SupportMapFragment.newInstance();
        getSupportFragmentManager().beginTransaction().replace(R.id.map, mapFragment).commit();
    }

    mapFragment.getMapAsync(this);
    map = mapFragment.getMap();


    map.setOnMyLocationChangeListener(myLocationChangeListener);
}

EDIT:

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

    mUiSettings = map.getUiSettings();
    mUiSettings.setZoomControlsEnabled(true);
    mUiSettings.setCompassEnabled(true);

    updateMyLocation();


}

Can you explain a bit more on why and how does it solve the problem? — anon
– anon, Commented Aug 7, 2015 at 6:07
ActionBarActivity already extends FragmentActivity @IntelliJ Amiya — Nguyễn Hoài Nam
– Nguyễn Hoài Nam, Commented Aug 7, 2015 at 6:19
Yes ,Mind it ActionBarActivity is deprecated .I here i used Appcompat instead ABA — IntelliJ Amiya
– IntelliJ Amiya, Commented Aug 7, 2015 at 6:24

Nguyễn Hoài Nam · Accepted Answer · 2015-08-07 06:39:08Z

1

By calling mapFragment.getMapAsync(this);, I suppose you have to override this method public void onMapReady(GoogleMap googleMap). Set your mMap = googleMap there and set all other listener there. Keep in mind that your Map object needs some time to be initialised, that's why they give you getMapAsync method.

Editted:

Please remove this from your onCreated

map = mapFragment.getMap(); map.setOnMyLocationChangeListener(myLocationChangeListener);

and put ~~them~~ map.setOnMyLocationChangeListener(myLocationChangeListener); inside your onMapReady() after this line map = mMap. Please acknowledge when your map is initialized.

edited Aug 7, 2015 at 6:39

answered Aug 7, 2015 at 6:21

Nguyễn Hoài Nam

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4 Comments

anon Over a year ago

I am already overriding onMapReady. I have included it in the EDIT.

Nguyễn Hoài Nam Over a year ago

Well, REMOVE this map = mapFragment.getMap(); map.setOnMyLocationChangeListener(myLocationChangeListener); from your onCreated. As I said, your map is still null at this moment.

anon Over a year ago

@Nguyen : So should I set my map to mapFragment.getMap(); or GoogleMap mMap?

Nguyễn Hoài Nam Over a year ago

Oh my bad, map = mMap; map.setOnMy..... Don't need to call your fragment anymore

Hamid Shatu · Accepted Answer · 2015-08-07 06:21:21Z

0

When you work with GoogleMap then it takes time to initialize. Sometimes it takes longer time in some devices than others.

To solve this issue, you should initialize the GoogleMap object with some delay. You can follow the below strategy:

private Handler handler = new Handler();

private Runnable mapChecker = new Runnable() {

    @Override
    public void run() {
        try {

            if (mapFragment.getMap() != null) {

                map = mapFragment.getMap();
                map.setOnMyLocationChangeListener(myLocationChangeListener);

                return;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        handler.postDelayed(mapChecker, 500);
    }
};

Then from onCreate(),

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

    ..........

    handler.postDelayed(mapChecker, 500);

    ..........

}

answered Aug 7, 2015 at 6:21

Hamid Shatu

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2 Comments

Nguyễn Hoài Nam Over a year ago

Since new API have getMapAsync method and onMapReady callback method, you don't need this anymore. Take a look at my Answer.

Hamid Shatu Over a year ago

since lately I didn't with GoogleMap, I was unaware of this callback. Now, I see this...its good.

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