@Override
 public boolean onOptionsItemSelected(MenuItem item) {
   if (item.getItemId() == R.id.action_clear_history) {
     Dialogue.askForConfirmation(
         this,
         R.string.clear_history,
         new View.OnClickListener() {
           @Override
           public void onClick(View v) {
             dbConn.clearHistory();
             calendar.updateContents();
           }
         });
     return true;
   }
   return super.onOptionsItemSelected(item);
 }