Getting ListView item ID from its ListAdapter's row ID
I am trying to create a single-choice (e.g., radio button) list of items that are queried from a database. To work with the currently selected row, I need to use the getCheckedItemPosition()
and setItemChecked()
methods of ListView.
I have a ListView
that has a SimpleCursorAdapter
set on it. When I retrieve the currently selected item, I have its 开发者_如何学Pythonrow ID from the database, which I need to use to find the appropriate item and manually set it to be selected via the aforementioned methods. In other words, I need to map the status of a row ID to a necessarily monotonic row ID (because the setItemChecked()
method accepts a position ID, not a database row ID, and in my database I can remove items).
So is there a way I can get a position id from a table row id? I'd rather not resort to doing a search if possible.
Thanks.
I ended up just creating a simple method that searches through all the items (which are assumed to be in order):
/**
* Since Android apparently provides no way to do this, do a simple binary
* search for the item position based on its row id.
* @param adapter The adapter to use
* @param row The rowId to search for
* @param left
* @param right
* @return Position, or -1 if not found
*/
public int getPositionFromRowId(ListAdapter adapter, long row, int left, int right) {
if (left > right)
return -1;
int middle = (left + right) / 2;
if (adapter.getItemId(middle) == row)
return middle;
if (adapter.getItemId(middle) > row)
return getPositionFromRowId(adapter, row, left, middle - 1);
else
return getPositionFromRowId(adapter, row, middle + 1, right);
}
Edit: Use this code by doing something like this:
getPositionFromRowId(myListAdapter, row, 0, myListAdapter.getCount());
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