Question

I have an Activity which I start like this:

public class MyProblemsActivity extends ListActivity 
{
    String[] PROBLEMS = new String[] {"One", "Two", "Three" };
    ArrayAdapter adapter;       

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);

        adapter = new ArrayAdapter<String>(this,R.layout.my_problems, PROBLEMS);

        setListAdapter(adapter);

        ListView lv = getListView();
        lv.setTextFilterEnabled(true);

and that works totally fine.

The problem I run into is after a call to a remote server via a Asynch call, I do this:

    @Override
    protected void onPostExecute(String result) 
    {       
            PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };
            adapter.notifyDataSetChanged();
        }

But the screen does not update. What am I doing wrong here and how can I get the screen to update with the new values?

Thanks!!

Answer 1

what’s happening is at

PROBLEMS = new String[] {"Hello", "Bye", "Hmmmmmm" };

the PROBLEMS is getting the reference to new string array object…Thus the old reference is remaining as it is(unchanged)..

to correct it, use following :

PROBLEMS.clear();
List<String> newlist = new ArrayList<String>();
newlist.add(..);
..
PROBLEMS.addAll(newlist);
adapter.notifyDataSetChanged();

this way new string(s) will be added only to existing array reference pointed out by PROBLEMS

NOTE: i have mentioned by referencing the use of arraylist of string instead of string[] , to use clear(),addAll() functionalites of it, you can modify it for String[] as per your use..