Question

I have an ExpandableListView and an ExpandableListAdapter. When I call notifyDataSetChanged() in my adapter, the data is not refreshed until I collapse and then expand the group. Here’s the code in question.

First, my activity (the relevant parts)

public class HomeActivity extends ExpandableListActivity {

Building of the adapter and list

homeList = (ExpandableListView)this.findViewById(android.R.id.list);
homeAdapter = new ExpandableHomeAdapter(this, profile.Statements, getItems(itemCount));
homeList.setAdapter(homeAdapter);
homeList.setIndicatorBounds(0,0);
homeList.setOnChildClickListener(this);

homeList.expandGroup(0);
homeList.expandGroup(1);

In this activity, I have an event that the activity is registered for that lets it know the model data (stored in the application controller), has changed. Here is that event.

private DataChangedListener dataChanged = new DataChangedListener() {

    @Override
    public void dataChanged(DataChangedEvent event, ChangeModel changes) {
        profile = Controller.getProfile();

        for (int x = 0; x < changes.NewItems.length; x++) {
            homeAdapter.insertItem(changes.NewItems[x], x);
        }

        for (int x = 0; x < changes.NewStatements.length; x++) {
            homeAdapter.insertStatement(changes.NewStatements[x], x);
        }

    }
};

And then there is my adapter

public class ExpandableHomeAdapter extends BaseExpandableListAdapter {

The insert method

public void insertItem(ItemSummary item, int index) {
    items.add(index, item);

    this.notifyDataSetChanged();
}

This same approach using the notifyDataSetChanged() worked when I was using multiple ArrayAdapters. Now, however, while everything works and the data is in fact changed, the screen does not update with the new data until I (manually) collapse and then expand the group. I haven’t tried programatically collapsing/expanding but I’d like to save that as a last resort. How do I get the view to update when the data changes?

Answer 1

I think this is happening because of the way in which you’re inflating the ExpandableListView. Try this: Instead of doing a findViewById to grab the ELV, call the setContentView of the layout that contains the ExpandableListView. Then call:

 ExpandableListView homeList = getExpandableListView();

Also, is there a way for you to call the notifyDataSetChanged() method from outside the class. Maybe you could call it from the same place you call the InsertItem method.