Java Micro Edition (J2ME) - 从记录存储中删除元素

发布于 2024-08-28 08:25:44 字数 941 浏览 8 评论 0原文

我有一个记录存储，其中包含购物商品列表，我目前正在序列化数据，如下所示

** (inside) ItemClass **            
ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
DataOutputStream dataOutputStream = new DataOutputStream(byteOutputStream);

dataOutputStream.writeUTF(getOwner());
dataOutputStream.writeUTF(getItemName());
dataOutputStream.writeInt(getQuantity());

dataOutputStream.close();

return byteOutputStream.toByteArray();

然后将字节数组写入记录存储，如下所示（对每个 id 使用 for 循环）

for (int i = 1; i <= shoppingListStore.getNumRecords(); i++)
{
     byte[] itemRecord = shoppingListStore.getRecord(i);
     newItemObject.fromByteArray(itemRecord);
     userShoppingList.append(newItemObject.getItemName() + " " + newItemObject.getQuantity() + " " + newItemObject.getOwner(), null);
}

问题来自于使用 ID 来遍历记录存储，因为这可能会因删除等而改变，因此我不断收到无效的 id 被抛出。我知道我不能使用 For every ItemObj : Recordstore 那么我如何遍历记录存储而不必担心 ids ？

原文

I have a record store which holds a list of shopping items i am currently serialising the data like so

** (inside) ItemClass **            
ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
DataOutputStream dataOutputStream = new DataOutputStream(byteOutputStream);

dataOutputStream.writeUTF(getOwner());
dataOutputStream.writeUTF(getItemName());
dataOutputStream.writeInt(getQuantity());

dataOutputStream.close();

return byteOutputStream.toByteArray();

This byte array is then written to the record store like so (using for loop for each id)

for (int i = 1; i <= shoppingListStore.getNumRecords(); i++)
{
     byte[] itemRecord = shoppingListStore.getRecord(i);
     newItemObject.fromByteArray(itemRecord);
     userShoppingList.append(newItemObject.getItemName() + " " + newItemObject.getQuantity() + " " + newItemObject.getOwner(), null);
}

The problem comes from using the ID to treverse through the record store as this may change from deletion etc and as such i keep geting invalid id being thrown. I know i cannot use For each ItemObj : Recordstore so how do i treverse through the record store without having to worry about ids ?

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