Why can't one add/remove items from an ArrayAdapter?

Question

I am using an ArrayAdapter to populate the items to list in a android.widget.Spinner. That works all fine.

But now I wa

Answer 1

I was having the same problem, my data was saved in resource String Array, so I was creating ArraAdapter with createFromResource.
The following code for creating ArrayAdapter from resource String Array solved the problem:

Resources res = getResources();
String[] cities = res.getStringArray(R.array.cities_array);
ArrayAdapter adapter = new ArrayAdapter(
     this,
     android.R.layout.simple_spinner_item,
     new ArrayList(Arrays.asList(cities)));