Question

我在Android中开发了一个基于测验的应用程序。现在，当我试图以降低顺序排列高分时，问题就出现了。我收到错误invalid LIMIT clauses:score DESC。我在这里发布了我的数据库类和我试图以降低顺序获取高分的类。请帮我解决这个错误。

DBAdapter.java

public long addscore(String name, int score)
{

    ContentValues values = new ContentValues();
    values.put(KEY_name, name); 
    values.put(KEY_score, score);

    return db.insert(DATABASE_TABLE1, null, values);
}
public Cursor getScore() throws SQLException 
{

    String order = KEY_score + " DESC ";
    /*return db.query(DATABASE_TABLE1, new String[] {KEY_scoreid, KEY_name,
            KEY_score}, null, null, null, null, order);*/
    Cursor mCursor = db.query(true, DATABASE_TABLE1, new String[] {
            KEY_scoreid, KEY_name,KEY_score },null, null,null,null, null,order);
    if (mCursor != null) 
    {
        mCursor.moveToFirst();
    }
    return mCursor;
}

Highscore.java

    try
    {
        db1=new DBAdapter(this);
        db1.open();
        c=db1.getScore();

        n1=c.getString(1);
        s1=c.getInt(2);
        n2=c.getString(1);
        s2=c.getInt(2);
        n3=c.getString(1);
        s3=c.getInt(2);
        n4=c.getString(1);
        s4=c.getInt(2);
        n5=c.getString(1);
        s5=c.getInt(2);

        name1.setText(n1);
        score1.setText(Integer.toString(s1));
        name2.setText(n2);
        score2.setText(Integer.toString(s2));
        name3.setText(n3);
        score3.setText(Integer.toString(s3));
        name4.setText(n4);
        score4.setText(Integer.toString(s4));
        name5.setText(n5);
        score5.setText(Integer.toString(s5));

    }
    catch(Exception ex)
    {
        Toast.makeText(getBaseContext(), ex.getMessage(), Toast.LENGTH_SHORT).show();
    }

我需要你的帮助，请帮忙！

先谢谢。

Answer 1

查询应该是那样的

Cursor mCursor = db.query(true, DATABASE_TABLE1, new String[] {
            KEY_scoreid, KEY_name,KEY_score },null, null,null,null,KEY_score + " DESC",null);

Answer 2

试试如下：

Cursor mCursor =db.query(DATABASE_TABLE1, new String[] {KEY_scoreid,KEY_name,KEY_score}, null, null, null, null, KEY_score + " DESC");

<强>编辑：

if (cur.getCount() > 0)
            {
                if (cur.moveToFirst())
                {
                    do
                    {
                        id1 = cur.getInt(0);
                        name = cur.getString(1);
                       Contacts contact_list = new Contacts(id1, name);
                        contact.add(contact_list);
                    } 
                    while (cur.moveToNext());
                }
                cur.deactivate();
                cur.close();
                cdb.close();
            }

Contact如下所示：

public class Contacts
{
    private int Id;
    private String NAME;
    public int getId()
    {
        return Id;
    }
    public void setId(int id)
    {
        this.Id = id;
    }
    public String getNAME()
    {
        return NAME;
    }
    public void setNAME(String name)
    {
        NAME = name;
    }
     public Contacts(int id, String name)
    {
        super();
        this.Id = id;
        NAME = name;
    }
}

从数据库中按降序获取高分数时出错

2 个答案: