title: flutter SearchDelegate how to display result without clicking magnifying glass
body: <p>i have a listTile storing the query, how can i display search result directly once i click on the listTile?</p>
  <pre><code>    ListTile(
                  onTap: () {
                    showSearch(
                      context: context,
                      query: query,
                      delegate: DataSearch(),
                    );
                  },
  ....
                ),
  </code></pre>
  <p>now its just a prefilled textfield..i need to click on the button to perform search, how can i skip this step?</p>
  <p><a href="https://i.stack.imgur.com/vZfFn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vZfFn.png" alt="enter image description here" /></a></p>