NullPointerException on getWritableDatabase after adding Fragments to my project

I had a working project, now I wanted to upgrade the layout and I'm trying to add Fragments (pre honeycomb), but now seems like I'm having some troubles connecting to my DB, and I'm getting NullPointerException:

ERROR/AndroidRuntime(272开发者_Python百科94):     
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:118)
ERROR/AndroidRuntime(27294):    
at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:187)

I believe it has something to do with the Context i'm sending to the database constructor.

here is my class:

public class ShowFragment extends ListFragment {

 ArrayList<String> results = new ArrayList<String>();
 private SQLiteDatabase db;
 WorkTrackdb workdb = new WorkTrackdb(getActivity());
 private ViewGroup mRootView;


@Override

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

     Cursor c = getYears();
             //some code here
}


    Cursor getYears() {
        db = workdb.getReadableDatabase();
        String years[] = {"year"};
        Cursor cursor = db.query(WorkTrackdb.TABLE_NAME, years, null,
                null, null, null,"year DESC");
        return cursor;
    }

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Try using SQLiteDatabase.openDatabase(String path, SQLiteDatabase.CursorFactory factory, int flags) instead.

I'm not sure maybe you need to instantiate WorkTrackdb workdb = new WorkTrackdb(getActivity()); inside the onCreate()