Android: HowTO delete last item of a list and the list

I have an activity which extends ListActivity. It has many things but amongst them it shows the articles the user has purchased with an adapter. Well I have a method that the user can delete the items from the list. The problem is when there is only one item. If I try to delete the last one the app crashes. Here is a it of my code:

public class Ventas extends ListActivity {

......

lv = getListView();

......

 protected void confirmRemoval(final int arg2) {
    // TODO Auto-generated method stub
    AlertDialog alertDialog = new AlertDialog.Builder(this).create();
    alertDialog.setTitle(getResources().getString(R.string.ventas));
    alertDialog.setMessage(getResources().getString(R.string.confirmacion2));
    alertDialog.setButton("Si",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                    if(adapter2.mEvents.size()>=1){
                    adapter2.mEvents.remove(arg2);
                    } else {

                        //doesn't work
                        /*adapter2=null;
                        adapter2.notifyDataSetInvalidated();
                        lv.setVisibility(View.GONE);*/
                    }

                }
            });
    alertDialog.setButton2("No", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            dialog.dismiss();
        }
    });

    alertDialog.show();


}

here is the adapter and wrapper:

private class EventAdapter2 extends BaseAdapter {

    public ArrayList<Articulo> mEvents = null;

    public EventAdapter2(Context c, ArrayList<Articulo> clientes) {
        mContext = c;
        mEvents = clientes;
    }

    public int getCount() {
        return mEvents.size();
    }

    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        EventEntryView2 btv;
        if (convertView == null) {
            btv = new EventEntryView2(mContext, mEvents.get(position));

        } else {
            btv = (EventEntryView2) convertView;
            String title1 = mEvents.get(position).getCantidad() + "";

            if (title1 != null) {
                btv.setText1Title(title1);
            }

            String title2 = mEvents.get(position).getDescripcion();

            if (title2 != null) {
                btv.setText2Title(title2);
            }

            String title3 = mEvents.get(position).getpVenta() + "0";

            if (title3 != null) {
                btv.setText3Title(title3);
            }

            String title4 = (mEvents.get(position).getCantidad() * mEvents
                    .get(position).getpVenta()) + "0";

            if (title4 != null) {
                btv.setText4Title(title4);
            }

        }

        return btv;

    }

    private Context mContext;

}

private class EventEntryView2 extends LinearLayout {

    private TextView text1;
    private TextView text2;
    private TextView text3;
    private TextView text4;
    private View inflatedView;

    public EventEntryView2(Context context, Articulo resp) {
        super(context);
        this.setOrientation(VERTICAL);

        inflatedView = View.inflate(context, R.layout.results, null);
        text1 = (TextView) inflatedView.findViewById(R.id.textView1);
        text2 = (TextView) inflatedView.findViewById(R.id.textView2);
        text3 = (TextView) inflatedView.findViewById(R.id.textView3);
        text4 = (TextView) inflatedView.findViewById(R.id.textView4);

        String t = resp.getCantidad() + "";
        text1.setText(t);

        String t1 = resp.getDescripcion();
        text2.setText(t1);

        String t2 = resp.getpVenta() + "0";
        text3.setText(t2);

      开发者_如何学运维  String t3 = (resp.getCantidad() * resp.getpVenta()) + "0";
        text4.setText(t3);

        addView(inflatedView, new LinearLayout.LayoutParams(
                LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

    }

    public void setText4Title(String title4) {
        text4.setText(title4);
    }

    public void setText3Title(String title3) {
        text3.setText(title3);
    }

    public void setText2Title(String title2) {
        text2.setText(title2);
    }

    public void setText1Title(String title1) {
        text1.setText(title1);

    }
}

as you can see when I have only one item left I have tried to set adapter to null or adapter.notifyDataSetInvaliadted or even making the listview invisible, nothing works. What happens is when I click ok nothing changes then when I click a second time it all crashes

What I would like is the listView to disappear when the adapter is empty but I am now out of ideas, is it even possible? Any ideas?

EDIT: Thank you all for the answers but the problem was I was modifying the list from inside an inner anonymous class. It is actually pretty simple, create a method and call it from inside the dialog, once the array is empty the list disappears automatically:

 protected void removeFromList(int arg2) {  
    adapter2.mEvents.remove(arg2);
    adapter2.notifyDataSetChanged();
  }

---

remove item from the arraylist which you add into the adapter and then call this method.

youradapter.notifyDataSetChanged();

and whatever you do for single item that was

adapter2 = null;
adapter2.notifyDataSetInavlidated();

this will obviously crash it because adapter2 object was null so how null object notify its data

---

Try calling lv.invalidate() after the remove() and see whether that makes any difference.

---

You should check in your adapter class if it is null then you should not fetch value from it......that's the main reason why you are getting exception as you are fetching the value from null variable.Put check there.

---

For setVisibility to Work:

1. You create your main.xml

2. Add to it a ListView

   <?xml version="1.0" encoding="utf-8"?>
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:app="http://schemas.android.com/apk/res/sherif.android.deedz" 
       android:orientation="vertical" android:layout_width="match_parent"
       android:layout_height="match_parent">
   <ListView android:layout_width="match_parent"
   android:layout_height="match_parent" android:id="@+id/myListView"
   android:divider="#ffa500" android:dividerHeight="1px"
   android:background="@drawable/somedrawable_xml"        
   android:choiceMode="singleChoice"></ListView>
   </ListView>
   

---

Now you can make it GONE

If you want the whole details of this : Check my answer