标签：lan null use tostring roi 提取 blog blank 不能
Android中数据库处理使用cursor时，游标不是放在为0的下标，而是放在为-1的下标处开始的。
也就是说返回给cursor查询结果时，不能够马上从cursor中提取值。
下面的代码会返回错误
User u = null; SQLiteDatabase db = dbHelper.getReadableDatabase(); Cursor cursor = db.rawQuery("select * from user where id = ?", new String[] { id.toString() }); Integer uid = cursor.getInt(cursor.getColumnIndex("id")); String uname = cursor.getString(cursor.getColumnIndex("name")); float uamount = cursor.getFloat(cursor.getColumnIndex("amount")); u = new User(uid, uname, uamount);cursor.close();
正确的用法
User u = null; SQLiteDatabase db = dbHelper.getReadableDatabase(); Cursor cursor = db.rawQuery("select * from user where id = ?", new String[] { id.toString() }); if (cursor.moveToFirst()) { Integer uid = cursor.getInt(cursor.getColumnIndex("id")); String uname = cursor.getString(cursor.getColumnIndex("name")); float uamount = cursor.getFloat(cursor.getColumnIndex("amount")); u = new User(uid, uname, uamount); } cursor.close();
Android android.database.CursorIndexOutOfBoundsException:Index -1 requested, with a size of 1
标签：lan null use tostring roi 提取 blog blank 不能
原文地址：http://www.cnblogs.com/zhujiabin/p/6393123.html
