greenDAO : NullPointerException at insert

Question

I'm using greenDAO for a Android project, I have to say I'm really happy with it.

Sadly, I'm currently having quite a strange problem : a NullPointerException while doing an insert, using the LocationCoordsDao, of a newly created LocationCoords object. It's only happening for this specific entity because insertions in Meal entity for example works well.

Here is my description :

public class MealsDiaryGenerator {

    public static void main(String[] args) {
        Schema schema = new Schema(2, "ch.cidzoo.journalibs.db");

        addMeal(schema);

        try {
            new DaoGenerator().generateAll(schema, "../JournalIBS/src");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void addMeal(Schema schema) {
        Entity loc = schema.addEntity("LocationCoords");
        loc.addIdProperty().autoincrement();
        loc.addDoubleProperty("latitude").notNull();
        loc.addDoubleProperty("longitude").notNull();

        Entity meal = schema.addEntity("Meal");
        meal.addIdProperty();
        meal.addDateProperty("date");
        Property locId = meal.addLongProperty("locationCoordsId").getProperty();
        meal.addToOne(loc, locId);
    }

}

And now where it fails :

@Override
public void onLocationChanged(Location location) {
    double lat = location.getLatitude();
    double lon = location.getLongitude();

    Log.i("onLocationChanged", "got a location update: lat=" + lat + " / lon=" + lon);

    LocationCoords loc = new LocationCoords(null, lat, lon);
    locationCoordsDao.insert(loc); //NullPointerException
    Log.d("DaoExample", "Inserted new coord, ID: " + loc.getId());

    Meal meal = new Meal(null, new Date(), null);
    mealDao.insert(meal);
    Log.d("DaoExample", "Inserted new meal, ID: " + meal.getId());
    ((MealAdapter)getListAdapter()).updateMeals(mealDao.loadAll());
}

I've tried to swap the insertions (meal before) with no effect. I've also tried all constructors for the LocationCoords entity with no more luck.

Any help would be greatly appreciated!

Where did you initialize `locationCoordsDao`? – Nizam Nov 26 '13 at 07:55 — Nizam, Nov 26 '13 at 07:55

score 1 · Accepted Answer · answered Feb 03 '14 at 22:03

You have to intiate your DAO first before you start using it. It's like this

 DevOpenHelper helper = new DaoMaster.DevOpenHelper(this.getActivity(),
            "DB name", null);
    db = helper.getWritableDatabase();
    mDaoMaster = new DaoMaster(db);
    mDaoSession = mDaoMaster.newSession();
    LocationCoordsDao mLocationCoordsDao = mDaoSession.getLocationCoordsDao();

then you can

    LocationCoords loc = new LocationCoords(null, lat, lon);
    mLocationCoordsDao.insert(loc); // init before use

greenDAO : NullPointerException at insert

1 Answers1