AutoCompleteTextView OnItemClick position is always "0"

Don't ask me why, but the argument position in method OnItemClickListener.onItemClick holds the index relative to the AutoCompleteTextView's dropdown list, not the position in your adapter array (in your case regions)!

So, to find the item's real position you must get the string selected in the dropdown and find its index in the adapter array:

String[] regions = ct.getRegions();
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, regions);
regionT.setAdapter(adapter);
regionT.setOnItemClickListener(new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        String selected = (String) parent.getItemAtPosition(position);
        int pos = Arrays.asList(regions).indexOf(selected);
    }
});