Android add dynamic elements to a listActivity

public class ListViewDemo extends ListActivity { //LIST OF ARRAY STRINGS WHICH WILL SERVE AS LIST ITEMS ArrayList<String> listItems=new ArrayList<String>(); //DEFINING STRING ADAPTER WHICH WILL HANDLE DATA OF LISTVIEW ArrayAdapter<String> adapter; //RECORDING HOW MUCH TIMES BUTTON WAS CLICKED int clickCounter=0; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems); setListAdapter(adapter); } //METHOD WHICH WILL HANDLE DYNAMIC INSERTION public void addItems(View v) { listItems.add("Clicked : "+clickCounter++); adapter.notifyDataSetChanged(); } }