Android - 将sqlite数据库中的值加载到arraylist

Question

我是android的新手.我有一个使用SQLite DB的应用程序.我需要将值从数据库推送到类型为object的arraylist.我使用的代码在这里给出.

 private ArrayList<objectname> objectList  = new ArrayList<objectname>();
 //function used to get values from database
   public ArrayList<objectname> getResults() {

    MyDb db = new MyDb(this); //my database helper file
    db.open();
    Cursor c = db.getAllValues(); //function to retrieve all values from a table- written in MyDb.java file
    if (c.moveToFirst())
    {
        do {         
            String date = c.getString(c.getColumnIndex("date"));

            try
            {
                ob = new objectname();
                ob.setDate(c.getString(c.getColumnIndex("date")));// setDate function is written in Class file
                objectList.add(ob);
            }
            catch (Exception e) {
             Log.e(MY_DEBUG_TAG, "Error " + e.toString());
            }

         } while (c.moveToNext());
    }
       db.close();
       return objectList;
}

这不能正常工作.没有显示任何错误,但我没有得到arraylist objectList的值

请帮帮我..谢谢你...

Answer 1

试试这个:

private ArrayList<objectname> objectList  = getResults();

private ArrayList<objectname> getResults() {

    MyDb db = new MyDb(this); //my database helper file
    db.open(); 

    ArrayList<objectname> resultList = new ArrayList<objectname>();


    Cursor c = db.getAllValues(); //function to retrieve all values from a table- written in MyDb.java file
    while (c.moveToNext())
    {
        String date = c.getString(c.getColumnIndex("date"));

        try
        {
            ob = new objectname();
            ob.setDate(date);// setDate function is written in Class file
            resultList.add(ob);
        }
        catch (Exception e) {
            Log.e(MY_DEBUG_TAG, "Error " + e.toString());
        }

    }

    c.close();

    db.close();
    return resultList;
}