android – 为什么这个AlertDialog.Builder.setIcon不显示ic_menu_info图标？

new AlertDialog.Builder(this).setMessage(menuInfo).setNeutralButton("OK",new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface d,int i) {
   // do nothing – it will close on its own
  }
 })
 .setIcon(R.drawable.ic_menu_info).show();
 ...