ClassCastException with ListView when executing notifyDataSetChanged

Question

I have added a view to the header of listVivew,

    View TopSearch =  (View) View.inflate(this, R.layout.search, null);
    lv.addHeaderView(TopSearch, null, false);

And everything is fine until I try to execute (when data changes)

adapter.notifyDataSetChanged();

That always crash my application giving me following error:

> java.lang.ClassCastException: android.widget.HeaderViewListAdapter

If I remove header view then there is no error. Any suggestions? Thanks.

Hereunto

You need to use ListView.LayoutParams. Check [this question][1]. [1]: #4394275 – Impure

Answer 1

It seems that whenever you use header/footer views in a listview, your ListView gets wrapped with a HeaderViewListAdapter. You can fix this using the below code:

((YourAdapter)((HeaderViewListAdapter)lv.getAdapter()).getWrappedAdapter()).notifyDataSetChanged();

Anterior

My listView.getAdapter() isn't an instance of HeaderViewListAdapter after a footer view was added. – Soggy

Thanks a lot .I couldnt follow the below approach due to structure of my app – Similitude

@ono: that would be FooterViewListAdapter i think – Lurcher

Now i am getting android.widget.ExpandableListConnector cannot be cast to * – Track

Not so, see stanllysong.blogspot.ru/2013/08/javalangclasscastexception.html. – Magnification

Answer 2

API 18 and lower is confused about what it is wrapping. To help it, set your header and/or footer PRIOR to assigning the adapter. That way the correct wrapping takes place under the covers. Then remove the header/footer immediately after (if that is what you want).

myList.addFooterView(myFooterView);
myList.setAdapter(adapter);
myList.removeFooterView(myFooterView);

Brawny

Answer 3

As written in http://stanllysong.blogspot.ru/2013/08/javalangclasscastexception.html it should be done so:

HeaderViewListAdapter hlva = (HeaderViewListAdapter)l.getAdapter();
YourListAdapter postAdapter = (YourListAdapter) hlva.getWrappedAdapter();
postAdapter.notifyDataSetChanged();

Magnification

Answer 4

@mussharapp's answer is perfectly right and it works! However I find more convenient to simply cache your adapter on a member variable for later use before you do setAdapter():

mAdapter = new YourAdapter(ctx, items);
listView.addFooterView(v);
listView.setAdapter(mAdapter);

Evasion

Answer 5

The reason for class cast exception is that the listview did't wrapped to headerlistview. So we can't add footers or header to listview directly. So before setting adapter to listview, add dummy view as header or footer view. Then set adapter to listview. This makes listview to instance of headerviewslist. Then you can add and remove footers easily from listview as normal.

listview.addFooterView(new View(mContext));listview.setAdapter(yourAdapter): 

After setting adapter, you can add or remove footer listview.addFooterView(yourFooter); or listview.removeFooterView(yourFooter);

Overstudy

Answer 6

public class YourOwnList extends ListActivity {
    private EfficientAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        mAdapter = new EfficientAdapter(/*your parameters for the adapter*/);
    }

    private void yourMethod () {
        mAdapter.notifyDataSetChanged();
    }

    private static class EfficientAdapter extends CursorAdapter {
        // your adapter
    }
}

Jonell

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