use Activity Context instead of AsyncTask to Create ArrayAdapter inside onPostExecute
method as :
ArrayAdapter<String> adapter =
new ArrayAdapter<String>(Your_Current_Activity.this,
android.R.layout.simple_list_item_1, headlines);
setListAdapter(adapter);
EDIT : after log posted also change
xpp.setInput(getInputStream(url1), "UTF_8");
to
xpp.setInput(url1.openConnection().getInputStream(), "UTF_8");