title: Flutter wrap widget in listview
body: <p>I'd like to wrap column in <code>listview</code> so that as scroll down, search bar will disappear.
  I tried like this</p>
  
  <pre><code>new ListView(
     shrinkWrap: true,
      children: &lt;Widget&gt;[
         new Column(
           mainAxisSize: MainAxisSize.min,
            children: &lt;Widget&gt;[
              new GestureDetector(
                child: new Container(
                  color: Colors.grey[300],
                  child: new Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: new Card(
                      margin: const EdgeInsets.fromLTRB(4.0, 0.0, 4.0, 0.0),
                      child: new ListTile(
                        leading: new Icon(Icons.search),
                        title: new Text('Search',
                            style: new TextStyle(color: Colors.grey[600])),
                      ),
                    ),
                  ),
                ),
                onTap: () {
                  print(
                      'tapped');
                },
              ),
              new GridView.builder(
                itemCount: items.length,
                gridDelegate: new SliverGridDelegateWithFixedCrossAxisCount(
                    crossAxisCount: 2),
                itemBuilder: (BuildContext context, int index) {
                  return new GestureDetector(
                    child: new Card(
                      elevation: 5.0,
                      child: new Container(
                        decoration: new BoxDecoration(
                          image: new DecorationImage(
                            fit: BoxFit.cover,
                            image: NetworkImage(
                                'https://images.unsplash.com/photo-1533514114760-4389f572ae26?ixlib=rb-0.3.5&amp;ixid=eyJhcHBfaWQiOjEyMDd9&amp;s=4ada6181447db788f0fc94d5d2e35c63&amp;auto=format&amp;fit=crop&amp;w=500&amp;q=60'),
                          ),
                        ),
                      ),
                    ),
                    onTap: () {
                      showDialog(
                        barrierDismissible: false,
                        context: context,
                        child: new AlertDialog(
                          title: new Column(
                            children: &lt;Widget&gt;[
                              new Text("GridView"),
                              new Icon(
                                Icons.favorite,
                                color: Colors.green,
                              ),
                            ],
                          ),
                          content: new Text("Selected Item $index"),
                          actions: &lt;Widget&gt;[
                            new FlatButton(
                                onPressed: () {
                                  Navigator.of(context).pop();
                                },
                                child: new Text("OK"))
                          ],
                        ),
                      );
                    },
                  );
                },
              ),
            ],
          ),
      ],
    ),
  </code></pre>
  
  <p>But list view is invisible and console says </p>
  
  <blockquote>
    <p>Vertical viewport was given unbounded height. Viewports expand in the
    scrolling direction to fill their container.</p>
  </blockquote>
  
  <p>I tried insert <code>expanded</code> and <code>shrinkwrap</code> but still shows nothing.
  Anyone know how to fix this?</p>