Updating ListView data onItemClick - android-listview

Question

My code does update the ListView when onItemClick is fired but only if I replace the line "inside the onItemClick method"
categoryAdapter.notifyDataSetChanged();
with the line
lv.setAdapter(new CategoryAdapter(categories));
Should I replace the line as indicated above or the notifyDataSetChanged is what I should use? since the docs say that it should update the view as well.
besides, when I do that, the app runs but hitting the back button shuts the app down instead of go back to the last screen which what I like to see.
public class MainActivity extends ActionBarActivity {
ListView lv;
String[] categories = null;
private static String[] failCategories = {"a","b","c};
private static String[] category_a= { "a1","a2"};
CategoryAdapter categoryAdapter = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_categories);
lv = (ListView) findViewById(R.id.lvCategories);
categories = failCategories; //initial set
categoryAdapter = new CategoryAdapter(categories);
lv.setAdapter(categoryAdapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (position == 0){
categories = category_a;
categoryAdapter.notifyDataSetChanged();
}
}
});
}
private class CategoryAdapter extends ArrayAdapter<String>{
CategoryAdapter(String[] objects) {
super(getBaseContext(), R.layout.activity_categories,R.id.tvCategory, objects);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = super.getView(position, convertView, parent);
return convertView;
}
}
}

Answer 1

please try this part of code inside your code if you want to update respected item only, make sure category_a has equal items
Version 1
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
categoryAdapter.insert(position,category_a[position]);
categoryAdapter.notifyDataSetChanged();
}
Version 2
if you want to update whole listview with all items in category_a then
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
categoryAdapter.clear();
categoryAdapter.addAll(category_a);
categoryAdapter.notifyDataSetChanged();
}