title: Remove grey background for flutter alert dialog
body: <p>I have a CupertinoAlertDialog and AlertDialog in my Flutter app. every time the dialog pops up, everything behind it becomes darker. I would like to remove the background. how do I do that?</p>
  
  <pre><code>CupertinoDialogAction(
          child: Text('Delete',
                  style: TextStyle(color: Colors.red),
                ),
                onPressed: () async {
                  await CommentActivity.delete(postData[index]['id'])
                    .then((response) {
                    if (response) {
                      setState(() {
                        postData.removeAt(index);
                        createPageActivity();
                        renderPageActivity();
                      });
                      Navigator.of(context).pop();
                    }
                  });
                }
              )
            ],
          )
  </code></pre>