title: dialog.getWindow() returns null after dialog is created
body: <pre><code>@Override
  protected Dialog onCreateDialog(int id) {
      Dialog dialog = null;
      switch(id) {
      case DIALOG_ID:
          LayoutInflater inflater = getLayoutInflater();
          View InfoLayout = inflater.inflate(R.layout.info_dialog, null);
          AlertDialog.Builder b = new AlertDialog.Builder(MyActivity.this)
                  .setView(InfoLayout );
          initInfoDialog(dialog);
          return dialog;
  ...
  
  private void initInfoDialog(Dialog dialog) {
      //this line has the null pointer 
      WindowManager.LayoutParams lp = dialog.getWindow().getAttributes(); 
  </code></pre>
  
  <p>Why is dialog.getWindow() returning null in this case?</p>