如何在Android

Question

我正在尝试在列表视图滚动结束时获取Sqlite数据库表的总记录数。但主要问题是第一次计数是否准确。当我再次滚动结束计数是增量。假设我有181个记录总计数，并再次滚动到最后得到计数是362，再次滚动得到543，... 724，... 905等等。为什么不像181那样得到恒定值。有人帮我解决它？

这是我的代码，用于获取Constant类

中的记录总数

public final class Constant
{
    public static SQLiteDatabase db;
    public static MyDbHelper dbhelper;

   public static int GetLocalPages(Context context)
    {
        dbhelper = new MyDbHelper(context);
        dbhelper.onOpen(db);

        String query = "select count(*) from ALL_Post";
        db = dbhelper.getWritableDatabase();
        Cursor c = db.rawQuery(query, null);
        if (c.moveToFirst())
        {
            totalRowCount += c.getInt(0);
            Log.e("11111 ", " totalRowCount = " + totalRowCount);
        }
        if(totalRowCount < 50)
        {
            num= 1 ;
            Log.e("22222 "," num=  " +  num);
        }
        if(totalRowCount > 50)
        {
            num= totalRowCount / 50;
            Log.e("33333 ", " num=  " + num);
        }
        if(totalRowCount % 50> 0)
        {
            num += 1;
            Log.e("44444 ", " num =  " + num );
        }
        return num ;
    }

 }

这是我的listView scrollListener方法

listView.setOnScrollListener(new AbsListView.OnScrollListener()
        {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {}

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                                 int visibleItemCount, int totalItemCount)
            {

                lastInScreen = firstVisibleItem + visibleItemCount;
                //Log.e("","lastInScreen="+lastInScreen);
                if(lastInScreen == totalItemCount)
                {
                    Toast.makeText(getApplicationContext(), "Your Last Item." + lastInScreen , Toast.LENGTH_SHORT).show();
int values= Constant.GetLocalPages(getApplicationContext());
                    Log.e("", "values=" + values);

                    }
            }
        });

Answer 1

不确定如何定义totalRowCount。但它看起来像一个定义的类变量，并且每次调用GetLocalPages(Context)时都会保持递增。这解释了这种行为。

Answer 2

指定totalRowCount = 0; 在调用数据库方法之前......

为什么你想要每卷都？ 这是你的数据库的数量...并且不会在滚动时改变。 你只需要一次。

Answer 3

你可以试试这个，

只需更改代码..

  public final class Constant
{
    public static SQLiteDatabase db;
    public static MyDbHelper dbhelper;

   public static int GetLocalPages(Context context)
    {
        dbhelper = new MyDbHelper(context);
        dbhelper.onOpen(db);
        int num =0;            

        String query = "select count(*) from ALL_Post";
        db = dbhelper.getWritableDatabase();
        Cursor c = db.rawQuery(query, null);
        num =c.getCount();
        return num ;
    }

 }

听众也有一些感情......

listView.setOnScrollListener(new AbsListView.OnScrollListener()
        {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {}

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                                 int visibleItemCount, int totalItemCount)
            {

                lastInScreen = firstVisibleItem + visibleItemCount;
                //Log.e("","lastInScreen="+lastInScreen);
                if(lastInScreen == totalItemCount)
                {
                    Toast.makeText(getApplicationContext(), "Your Last Item." + lastInScreen , Toast.LENGTH_SHORT).show();
             int values = 0;
             values= Constant.GetLocalPages(getApplicationContext());
                    Log.e("", "values=" + values);

                    }
            }
        });

我希望这会对你有所帮助。