Close SQLite Database in app with several activities

Question

I have class for work with SQLite database(PlaceDbProvider). It is singletone. The problem is that I have three activities that are use PlaceDbProvider. When it is better to call destroy method for PlaceDbProvider? I am confused because every activity has own onDestroy method.

public class PlaceDbProvider {
private static final String DB_NAME = "com.placesmanager";
private static final String TABLE_NAME = "places";
private static final int DB_VESION = 1;
private static final String KEY_ID = "_id";
private static final int ID_COLUMN = 0;
private static final String KEY_NAME = "name";
private static final int NAME_COLUMN = 1;

private Context context;
private Cursor cursor;
private SQLiteDatabase database;
private DbOpenHelper dbOpenHelper;

private static PlaceDbProvider mInstance = null;

private PlaceDbProvider(Context context) {
    this.context = context;
    init();
}

public static PlaceDbProvider getInstance(Context context) {
    if(mInstance == null) {
        mInstance = new PlaceDbProvider(context);
    }
    return mInstance;
}

public int getCount() {
    return cursor.getCount();
}


public Place getItem(int position) {
    if (cursor.moveToPosition(position)) {
        Place placeOnPositon = new Place();     
        placeOnPositon.setId(cursor.getLong(ID_COLUMN));
        placeOnPositon.setName(cursor.getString(NAME_COLUMN));
        return placeOnPositon;
    } else {
        throw new CursorIndexOutOfBoundsException(
                "Cant move cursor to postion");
    }
}


public long getItemId(int position) {
    if (cursor.moveToPosition(position)) {  
        return cursor.getLong(ID_COLUMN);
    } else {
        throw new CursorIndexOutOfBoundsException(
                "Cant move cursor to postion");
    }
}
public long addItem(Place place) {
    ContentValues values = new ContentValues();
    values.put(KEY_NAME, place.getName());
    long id = database.insert(TABLE_NAME, null, values);
    refresh();
    return id;
}
public boolean removeItem(Place placeToRemove) {
    boolean isDeleted = (database.delete(TABLE_NAME, KEY_NAME + "=?",
            new String[] { placeToRemove.getName() })) > 0;
    refresh();
    return isDeleted;
}

public boolean updateItem(long id, String key,String newValue) {
    ContentValues values = new ContentValues();
    values.put(key, newValue);
    boolean isUpdated = (database.update(TABLE_NAME, values, KEY_ID + "=?",
            new String[] {id+""})) > 0;
    return isUpdated;
}


public void destroy() {
    dbOpenHelper.close();
    mInstance = null;
}

private void refresh() {
    cursor = getAllEntries();
}

public Cursor getAllEntries() {

    String[] columnsToTake = { KEY_ID, KEY_NAME, KEY_LAT, KEY_LNG, KEY_TYPE, KEY_INFO, KEY_OWNER};

    return database.query(TABLE_NAME, columnsToTake,
            null, null, null, null, KEY_ID);
}

private void init() {
    dbOpenHelper = new DbOpenHelper(context, DB_NAME, null, DB_VESION);
    try {
        database = dbOpenHelper.getWritableDatabase();
    } catch (SQLException e) {
        Log.e(this.toString(), "Error while getting database");
        throw new Error("The end");
    }
    cursor = getAllEntries();
}

//class for creation, opening and db version control
private static class DbOpenHelper extends SQLiteOpenHelper {

    public DbOpenHelper(Context context, String name,
            CursorFactory factory, int version) {
        super(context, name, factory, version);
    }  

    @Override
    public void onCreate(SQLiteDatabase db) {
        final String CREATE_DB = "CREATE TABLE " + TABLE_NAME + " ("
                + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + KEY_NAME + " TEXT NOT NULL);";
        db.execSQL(CREATE_DB);

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);
    }
}

}

Answer 1

1)Instanciate PlaceDbProvider with application context (context.getApplicationContext() )

2)Create your application class

3)in your application class, in onTerminate() method, call (PlaceDbProvider) onDestroy() method

(see my other answer at this link for the creation of the application class : https://stackoverflow.com/a/13994622/1789730)