ExpandableListAdapter cannot be resolved to a type

Question

i have done this on my other android app and it worked flawlessly but when i do this in another app it doesnt work.

i keep getting an error saying "ExpandableListAdapter cannot be resolved to a type"

public class MainActivity extends Activity implements AdListener,
        OnClickListener {

    ExpandableListAdapter listAdap;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Full Screen
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);

        // get the list view
        expListView = (ExpandableListView) findViewById(R.id.lvExp);
        prepareListData();
        listAdap = new ExpandableListAdapter(this, listDataHeader, listDataChild);

        // setting list adapter, show the list
        expListView.setAdapter(listAdap);

        expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {

                    public boolean onChildClick(ExpandableListView parent,
                            View v, int groupPosition, int childPosition,
                            long id) {
                    }
                });
    }

Answer 1

ExpandableListAdapter is an interface, it cannot be instantiated. You should use SimpleExpandableListAdapter or extends BaseExpandableListAdapter and override its methods if you want more flexibility.