Android / Java：从多个活动访问相同的SQLite DB对象

private static DataHelper singleton;

    public static DataHelper getDataHelper(Context context) {
            if (singleton == null) {
                    singleton = new DataHelper(context);
                    OpenHelper openHelper = new openHelper(singleton.context);
                    singleton.db = openHelper.getWritableDatabase();
            }
            if(!singleton.db.isopen()){
                    OpenHelper openHelper = new openHelper(singleton.context);
                    singleton.db = openHelper.getWritableDatabase();
            }
            singleton.context = context;
            return singleton;
    }

    private DataHelper(Context context) {
        this.context = context;
}

并像这样打电话给你的单身人士课;

public DataHelper dh;
this.dh = DataHelper.getDataHelper(this);