Question

I have a ListView that is filled with a dynamic set of data each time the Activity is created. For simplicity’s sake, lets say each ListView item is a employee’s name. Under the hood, each employee has an employee_id number. This number is not visible anywhere in the interface.

When I click on an employee’s name in the ListView, I want to launch another activity, passing the corresponding employee’s employee_id to that Activity.

I understand how to implement the onClick handler for the ListView. My question is, where would I store and retrieve the employee_id for each employee? Would I simply store it in a hash/map along with the position in the list that the employee shows up at? And when I click, I just determine the position in the list I clicked at, and then get the employee_id from the hash using that position?

Answer 1

Use the ArrayAdapter with a list Employees – assuming you have Employee-object.

public class MyActivity extends ListActivity {
   // list of employees
   private List<Employee> employees = new ArrayList<Employee>();

Then use the position parameter in OnItemClick to get the employee-object.

 public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    int employee_id = ((Employee) getListAdapter().getItem(position)).getId();
    // ...
 }

You can also extend the ArrayAdapter to tailor the list for employee-objects:
How to use ArrayAdapter<myClass>