android: Identify individual items in row of ListV

Question

I have a ListView in a ListActivity populated by a database table. Each row of the ListView is a RelativeLayout with three TextViews named rowid, date, and name in that order. I am able to select individual rows programmatically using the .setSelection(int position) method of the ListView.

Here is what I'm trying to do: When I push a button on the interface, get the rowid from the currently selected list row, and perform a db query using the rowid. I can't figure out how to get the rowid from the list itself. rowid may not be the same as the ID or position on the list as it is the rowid in the database.

I suspect this will require working with an adapter, but I've been trying/searching the web for a week and haven't been able to figure this out. Thanks for the help anyone can provide.

Answer 1

You know the list position of the currently selected item, you have a button outside the ListView that should trigger some action on that item, and you're not just making the ListView rows (or some child view within each row) clickable. Right?

You can get information from the list's adapter. getItem(int position) returns the object that is represented by the list item at position, so you can retrieve the information you need directly if it's stored in the object. getView(int position) returns the view for the row, allowing you to use findViewById(int id) to retrieve your TextView.

If you don't already have the adapter, you can get it from the ListView using getAdapter().

// ListView myListView = the ListView in question
// int selectedRow = the currently selected row in the ListView
// Each row in the ListView is backed by an object of type MyCustomDataClass

int dbRowId;
Adapter adapter = myListView.getAdapter();

MyCustomDataClass data = (MyCustomDataClass) adapter.getItem(selectedRow);
dbRowId = data.getDatabaseRowId();
// OR
dbRowId = data.rowId;
// OR whatever method the object has for getting the ID.

// OR
View listViewRow = adapter.getView(selectedRow);
TextView dbRowView = (TextView) listViewRow.findViewById(R.id.rowid);
String dbRowAsString = dbRowView.getText().toString();
dbRowId = Integer.parseInt(dbRowAsString);

You might also consider whether it would be more natural for the user to just tap the ListView row, rather than selecting the row and then pressing another button. Reno's answer might work better.

Answer 2

I ended up using the last method with the following code.

int dbRowId;
Adapter adapter = myListView.getAdapter();

View listViewRow = adapter.getView(selectedRow);
TextView dbRowView = (TextView) listViewRow.findViewById(R.id.rowid, null, null);
String dbRowAsString = dbRowView.getText().toString();
dbRowId = Integer.parseInt(dbRowAsString);

The only change I had to make was adding null, null to the parameters in .findViewByID

TextView dbRowView = (TextView) listViewRow.findViewById(R.id.rowid, null, null);