从 SimpleCursorAdapter 访问 SQLite 值

发布于 2024-11-04 11:43:50 字数 2330 浏览 1 评论 0原文

我有一个名为“Nodes”的 SQLite 表，其中包含一组所有节点（每个节点都有多个属性）。

在一个活动中，我使用 SimpleCursorAdapter 的扩展来显示 Nodes 表的子集，基于 SQL 查询，将 Cursor 传递到结果表（来自查询）。

{id_long, name_string, description_string, nodetype_enum_toString...}
    1, "home", "home_desc", "cool"
    2, "item1", "item1_desc", "warm"
    3, "item2", "item2_desc", "hot"
    4, "item3", "item3_desc", "warm"
    5, "item4", "item4_desc", "hot"

我想修改 ListActivity 中的每个列表项，以便它根据项目是冷、暖还是热显示不同的颜色。我有一个小（空）视图，但它始终默认为白色（“其他”部分）。

public View getView(int position, View convertView, ViewGroup parent) {
    convertView = super.getView(position, convertView, parent);

    if (convertView == null) convertView = View.inflate(mContext, R.layout.viewstack_item, null);
    View nodetype_view = (View) convertView.findViewById(R.id.nodetype_view);

    mGenCursor_cur = mDataHelper_db.getAll();
    mGenCursor_cur.moveToPosition(position);

    Log.i("test", "node type key " + mGenCursor_cur.getColumnIndex(DataHelper.NODES_TYPE_KEY));
    String type_nt = mGenCursor_cur.getString(mGenCursor_cur.getColumnIndex(DataHelper.NODES_TYPE_KEY));
    String name_str = mGenCursor_cur.getString(mGenCursor_cur.getColumnIndex(DataHelper.NODES_NAME_KEY));
    Log.i("getView", title_str + "typeis " + type_nt + " at position " + position);

    if (prio_np.equals(NodePrio.HIGH.toString())) {
        Log.i("prio_np", "high red");
        prioView_view.setBackgroundColor(Color.RED);
    } else if (prio_np.equals(NodePrio.NORMAL.toString())) {
        Log.i("prio_np", "norm magenta");
        prioView_view.setBackgroundColor(Color.MAGENTA);
    } else {
        Log.i("prio_np", "else (low) white");
        prioView_view.setBackgroundColor(Color.WHITE);
    }

    mGenCursor_cur.close();
    bindView(convertView, mContext, getCursor());
    return(convertView);
}

我的问题是，虽然传递给 SimpleListAdapter 的光标将包含我想要的子集中相应节点的 _ID（我假设），但 getView 中的 position 参数是本地的到子集，所以我无法将它与节点表交叉引用。我是否缺少一些简单的技巧？

一如既往，任何帮助表示赞赏。

标记答案的评论4帮助我解决了这个问题：将传递给 SimpleCursorAdapter 的光标存储为成员变量，然后使用 move toposition 和 getLong:

mCursor_cur.moveToPosition(position);
long id = mCursor_cur.getLong(0);

其中 position 是 getView() 方法中的本地参数，0 用于 getLong，因为db_id 是传递给 SimpleCursorAdapter 的游标中的第一列

原文

I have a SQLite table called "Nodes" with a set of all nodes (each node has multiple properties).

In an activity, I use an extension of SimpleCursorAdapter to display a subset of the Nodes table, based on a SQL query, passing it the Cursor over the table of results (from the query).

{id_long, name_string, description_string, nodetype_enum_toString...}
    1, "home", "home_desc", "cool"
    2, "item1", "item1_desc", "warm"
    3, "item2", "item2_desc", "hot"
    4, "item3", "item3_desc", "warm"
    5, "item4", "item4_desc", "hot"

I want to modify each of the list items in my ListActivity such that it displays a different color based on whether an item is cool, warm or hot. I have a small (empty) view, but it's always defaulting to white (the 'else' portion).

public View getView(int position, View convertView, ViewGroup parent) {
    convertView = super.getView(position, convertView, parent);

    if (convertView == null) convertView = View.inflate(mContext, R.layout.viewstack_item, null);
    View nodetype_view = (View) convertView.findViewById(R.id.nodetype_view);

    mGenCursor_cur = mDataHelper_db.getAll();
    mGenCursor_cur.moveToPosition(position);

    Log.i("test", "node type key " + mGenCursor_cur.getColumnIndex(DataHelper.NODES_TYPE_KEY));
    String type_nt = mGenCursor_cur.getString(mGenCursor_cur.getColumnIndex(DataHelper.NODES_TYPE_KEY));
    String name_str = mGenCursor_cur.getString(mGenCursor_cur.getColumnIndex(DataHelper.NODES_NAME_KEY));
    Log.i("getView", title_str + "typeis " + type_nt + " at position " + position);

    if (prio_np.equals(NodePrio.HIGH.toString())) {
        Log.i("prio_np", "high red");
        prioView_view.setBackgroundColor(Color.RED);
    } else if (prio_np.equals(NodePrio.NORMAL.toString())) {
        Log.i("prio_np", "norm magenta");
        prioView_view.setBackgroundColor(Color.MAGENTA);
    } else {
        Log.i("prio_np", "else (low) white");
        prioView_view.setBackgroundColor(Color.WHITE);
    }

    mGenCursor_cur.close();
    bindView(convertView, mContext, getCursor());
    return(convertView);
}

My issue is that while the cursor passed to the SimpleListAdapter will contain the _IDs (I assume) of the corresponding nodes in the subset I want, the position parameter in getView is local to the subset, so I can't cross-reference it with the Nodes table. Am I missing some easy technique?

As always, any help appreciated.

comment 4 of the marked answer helped me solve this:
storing the cursor that was passed to the SimpleCursorAdapter as a member variable, then using move to position, and getLong:

mCursor_cur.moveToPosition(position);
long id = mCursor_cur.getLong(0);

where position is the local parameter in the getView() method, and 0 is used for getLong because the db_id is the first column in the cursor passed to the SimpleCursorAdapter

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