Google Map 在两项活动之间崩溃

我在我的应用程序中使用谷歌 Map . 第一次正确加载谷歌 Map 时，页面上有一个按钮，但再次转到该页面并单击该按钮会导致我的应用程序崩溃 .

这是我的代码：

public class GoogleMaps extends Activity {

    MapFragment googleMapFragment = null;
    private static GoogleMap googleMap = null;
    private String provider;
    MarkerOptions marker;
    double latitude, longitude;
    private LocationManager locationManager;
    ParseGeoPoint myLatLng[];
    int count_place, i = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.googlemap_view);
        try {
            initilizeMap();
            initParse();
        } catch (Exception e) {
            // TODO: handle exception
            Toast.makeText(getApplicationContext(), e.toString(),
                    Toast.LENGTH_SHORT).show();
        }
    }

    private void initParse() {
        // TODO Auto-generated method stub
        Parse.initialize(this, "key","key");
        ParseObject plcobj = new ParseObject("Details");
        getLatLong();
        ParseGeoPoint myGeoPiont = new ParseGeoPoint(latitude, longitude);
        ParseGeoPoint userLocation = (ParseGeoPoint) plcobj.get("location");
        final ParseQuery query = ParseQuery.getQuery("Details");
        query.whereNear("location", myGeoPiont);
        query.setLimit(10);
        query.whereWithinKilometers("location", myGeoPiont, 10);
        query.findInBackground(new FindCallback() {

            @Override
            public void done(List objects, ParseException e) {
                // TODO Auto-generated method stub

                if (e == null) {
                    Iterator Itr = objects.iterator();
                    while (Itr.hasNext()) {
                        ParseObject plcObjNext = (ParseObject) Itr.next();
                        myLatLng[i] = plcObjNext.getParseGeoPoint("location");
                        i++;  // Line 76

                    }
                }
            }
        });
    }

    private void initilizeMap() {
        if (googleMap == null) {
            googleMapFragment = ((MapFragment) getFragmentManager()
                    .findFragmentById(R.id.map));
            googleMap = googleMapFragment.getMap();
            googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

            if (googleMap == null) {
                Toast.makeText(getApplicationContext(),
                        "Sorry! unable to create maps", Toast.LENGTH_SHORT)
                        .show();
            }
            googleMap.setMyLocationEnabled(true);
            Log.e("Maps", "------EOC-------");
            // Get the location manager

        }
    }

    public void getLatLong() {
        GPSTracker gps = new GPSTracker(GoogleMaps.this);
        if (gps.canGetLocation()) {
            longitude = gps.getLongitude();
            latitude = gps.getLatitude();
            Toast.makeText(getApplicationContext(), longitude + " " + latitude,
                    Toast.LENGTH_SHORT).show();
        } // return boolean true/false
        else {
            gps.showSettingsAlert();
        }
    }
}

这是我的日志：

10-18 13:37:24.219 E/AndroidRuntime(21624): FATAL EXCEPTION: main
10-18 13:37:24.219 E/AndroidRuntime(21624): java.lang.NullPointerException
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.example.restaurantfinder.GoogleMaps$1.done(GoogleMaps.java:76)
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.parse.FindCallback.internalDone(FindCallback.java:45)
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.parse.FindCallback.internalDone(FindCallback.java:1)
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.parse.Parse$6$1.run(Parse.java:888)
10-18 13:37:24.219 E/AndroidRuntime(21624): at android.os.Handler.handleCallback(Handler.java:605)
10-18 13:37:24.219 E/AndroidRuntime(21624): at android.os.Handler.dispatchMessage(Handler.java:92)
10-18 13:37:24.219 E/AndroidRuntime(21624): at android.os.Looper.loop(Looper.java:137)
10-18 13:37:24.219 E/AndroidRuntime(21624): at android.app.ActivityThread.main(ActivityThread.java:4517)
10-18 13:37:24.219 E/AndroidRuntime(21624): at java.lang.reflect.Method.invokeNative(Native Method)
10-18 13:37:24.219 E/AndroidRuntime(21624): at java.lang.reflect.Method.invoke(Method.java:511)
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
10-18 13:37:24.219 E/AndroidRuntime(21624): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
10-18 13:37:24.219 E/AndroidRuntime(21624): at dalvik.system.NativeStart.main(Native Method)