Question

我有一个简单的SQLite原始查询函数，它看起来像：

public Cursor getOccurations ()
{
    SQLiteDatabase db =this.getWritableDatabase();
    Cursor data= db.rawQuery("select count(*) from Beacon_occurations where BEACON_ADDRESS='" + COL_2 + "' and TIME='" + COL_3 +"'", null);
    return data;
}

现在这是一个问题，我应该如何正确显示它？当我尝试做类似的事情时：

            data = db.getOccurations();
            string = data.toString();
            Log.e("Message",string);

我得到：消息：android.database.sqlite.SQLiteCursor@1a81ae97 ofc它不是我想要的数据:) 我该怎么做呢？

Answer 1

有关此类调试日志记录的目的，请查看DatabaseUtils#dumpCursorToString()。

出于非调试目的，请致电But when i use the code below if(freq.equals("new")),it shows invalid token. {String queue[] = {"Hi","How are you"} if(freq.equals("old")) String queue[] ={"Hi","How are you","take care"} }等。在光标上。

Answer 2

试试这个：

while(data.moveToNext()){
String s = data.getString(data.getColumnIndex("column Name"));
}

或

while(data.moveToNext()){
    String s = data.getString(0);
    }

Answer 3

使用帮助函数（例如longForQuery()或stringForQuery()）可以更轻松地从查询中读取单个值：

public long getOccurations()
{
    SQLiteDatabase db = getWritableDatabase();
    return DatabaseUtils.longForQuery(db,
            "select count(*) from Beacon_occurations where BEACON_ADDRESS=? and TIME=?",
            new String[]{ COL_2, COL_3 });
}

但是要计算行数，还有一个更简单的辅助函数queryNumEntries()：

public long getOccurations()
{
    SQLiteDatabase db = getWritableDatabase();
    return DatabaseUtils.queryNumEntries(
            db, "Beacon_occurations",
            "BEACON_ADDRESS=? and TIME=?",
            new String[]{ COL_2, COL_3 });
}

计算SQLite Android如何正确显示光标

3 个答案: