Android - 从 sqlite 数据库加载值到一个数组列表 [英] Android - load values from sqlite database to an arraylist

问题描述

我是 android 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对象的数组列表.此处给出了我使用的代码.

I am new to android . I have an application working with SQLite DB. I need to push values from database to an arraylist of type object. The code i used is given here.

 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，但我没有在 arraylist objectList 中获取值

This is not working correctly. Not shown any errors but i didn't get values in to the arraylist objectList

请帮助我..提前致谢..

Please help me..Thanks in advance..

推荐答案

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;
}

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