改变下拉列表文字显示大小

 ArrayAdapter<CaseResultItem> adapter = new ArrayAdapter<CaseResultItem> (this, android.R.layout.simple_spinner_dropdown_item, lst);
     adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  sp.setAdapter(adapter);
  sp.setOnItemSelectedListener(new OnItemSelectedListener() {

   @Override
   public void onItemSelected(AdapterView<?> parent, View view,
     int posinion, long id) {
    TextView tv = (TextView)view;
    tv.setTextSize(20);  //改变文字大小
   }

   @Override
   public void onNothingSelected(AdapterView<?> arg0) {
   }
  });