java.lang.NullPointerException for google map API v2

Question

I have been trying to solve this issue for ages and I can't find where the problem is. I am having trouble only with some devices that run Android 2.2. I tested on Android 4.1.2 and it works fine.

The error I am getting:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.coldice.plotfinder/com.coldice.plotfinder.MapFragment}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2668)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2684)
at android.app.ActivityThread.access$2300(ActivityThread.java:126)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2038)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4632)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.coldice.plotfinder.MapFragment.onCreate(MapFragment.java:67)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2632)
... 11 more

So looking back to my class MapFragment line 67 which is

 googleMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);

I am aware that googlemap API v2 requires API level 12 or higher as noted here, but I am using lower so I called

getSupportFragmentManager();

The MapFragment class code is below:

public class MapFragment extends SherlockFragmentActivity {
    private static final String TAG = "MapFragment";
    private GoogleMap googleMap;                                                    // Google map 
    private int mapType = GoogleMap.MAP_TYPE_SATELLITE;

    private Polyline polyline;;                                                     // Drawing the area of the land by using the polygon
    private boolean isDrawn=false;
    static String fileToBeRead =null;                                               // The file name to be read

    ArrayList<Cooridnates> cooridnatesList;
    // Image utility saving
    ImageSaveUtil imageUtil = new ImageSaveUtil();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        setTheme(R.style.Theme_Sherlock);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map);

        // Different colors for each marker
        float[] markerColours = {BitmapDescriptorFactory.HUE_AZURE,BitmapDescriptorFactory.HUE_BLUE,BitmapDescriptorFactory.HUE_CYAN,BitmapDescriptorFactory.HUE_GREEN,
        BitmapDescriptorFactory.HUE_MAGENTA,BitmapDescriptorFactory.HUE_ORANGE,BitmapDescriptorFactory.HUE_RED,BitmapDescriptorFactory.HUE_ROSE,
        BitmapDescriptorFactory.HUE_VIOLET,BitmapDescriptorFactory.HUE_YELLOW};

        // The code I am getting java.lang.NullPointerException
        FragmentManager fragmentManager = getSupportFragmentManager();
        SupportMapFragment mapFragment =  (SupportMapFragment)fragmentManager.findFragmentById(R.id.map);
        googleMap = mapFragment.getMap();
        googleMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);

        // If there is a file to be read, then read the coordinates 
        if(fileToBeRead!=null)
        {
            readData(fileToBeRead);
            fileToBeRead =null;
        }

            // Getting the coordinates List
        cooridnatesList = MainActivity.getList();
        if(cooridnatesList!=null)
        {
            // Adding a marker from each point
            for(int i=0;i<cooridnatesList.size();i++)
            {
                LatLng point = new LatLng(cooridnatesList.get(i).getLat(),cooridnatesList.get(i).getLon());
                googleMap.addMarker(new MarkerOptions()
                .position(point)
                .title("My Land")
                .snippet("Point: "+cooridnatesList.get(i).getLat()+","+cooridnatesList.get(i).getLon())
                .icon(BitmapDescriptorFactory.defaultMarker(markerColours[i%10])));

            }

            googleMap.getUiSettings().setCompassEnabled(true);                      // Setting the compass enabled in the map
            googleMap.getUiSettings().setZoomControlsEnabled(true);                 // Zooming is enabled
            googleMap.getUiSettings().setMyLocationButtonEnabled(true);             // My location button is enabled


            // Zooming the camera from the first point entered 
            LatLng cameraLatLng = new LatLng(cooridnatesList.get(0).getLat(),cooridnatesList.get(0).getLon());
            float cameraZoom = 10;

            if(savedInstanceState != null){
                mapType = savedInstanceState.getInt("map_type", GoogleMap.MAP_TYPE_SATELLITE);

                double savedLat = savedInstanceState.getDouble("lat");
                double savedLng = savedInstanceState.getDouble("lng");
                cameraLatLng = new LatLng(savedLat, savedLng);

                cameraZoom = savedInstanceState.getFloat("zoom",18);
            }

            // Setting the map type such as satellites or street view
            googleMap.setMapType(mapType);
            googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(cameraLatLng, cameraZoom));


            //Displaying the land area
            final TextView landInformation = (TextView)findViewById(R.id.textViewLandInformation);
            double area = calculateArea(cooridnatesList);
            landInformation.setText(getString(R.string.land_area)+"\n"+Math.round(area)+" SQ.M");

        }

    }

Answer 1

Try moving all code that references your GoogleMap to onStart() or onResume(). The map in a map fragment isn't instantiated until after the fragment has gone through onCreateView (link). Also, you need to check your googleMap for null, because if google play services aren't installed, or the map isn't available for some other reason, it will be null.