title: problem SingleChildScrollView with PageView flutter
body: <p>I want to add SingleChildScrollView in my page but i have PageView.</p>
  
  <pre><code> @override
    Widget build(BuildContext context) {
      return new Scaffold(
        appBar: new IneatAppBarPollWidget()
            .getAppBar('Blackblox', 'assets/img/logo_ineat.png', cand),
        body: new Center(
          child: SingleChildScrollView(
            child: new Column(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: &lt;Widget&gt;[
                new Expanded(
                  child: new Container(
                    child: new FutureBuilder&lt;List&lt;PollQuestionsDto&gt;&gt;(
                        future: _future,
                        // ignore: missing_return
                        builder: (context, snapshot) {
                          switch (snapshot.connectionState) {
                            case ConnectionState.none:
                              return Text('Failed connection API');
                            case ConnectionState.waiting:
                              return new Text('Wait...');
                            case ConnectionState.done:
                              if (snapshot.hasData) {
                                if (snapshot.data != null) {
                                  return PageView.builder(
                                    scrollDirection: Axis.horizontal,
                                    itemCount: snapshot.data.length,
                                    itemBuilder: (BuildContext context, index) {
                                      print(this.responses);
                                      return PollListViewItem(
                                        entitled: 
                                        snapshot.data[index].entitled,
                                        answers: 
                                        snapshot.data[index].answers,
                                        currentAnswer: 
                                        this.responses[index],
                                        onSelect: (Answer answer) {
                                          this.responses[index] = answer;
                                        },
                                      );
                                    },
                                  );
                                }
                              }
                              break;
                            case ConnectionState.active:
                          }
                        }),
                  ),
                ),
                new ProgressBar(),
                new Container(
                  margin: EdgeInsets.only(right: 10.0),
                  child: new RaisedButton.icon(
                    onPressed: () async {
                      //await Poll().submitPoll(answers: answers);
                      setState(() {
                        Navigator.pushReplacement(context,
                            MaterialPageRoute(builder: (context) =&gt; 
                            PollPage()));
                      });
                    },
                    label: Text('Suivant'),
                    icon: Icon(Icons.navigate_next),
                  ),
                  alignment: Alignment.bottomRight,
                ),
              ],
            ),
          ),
        ),
      );
    }
  }
  
  </code></pre>
  
  <p>When I added this, I have this error :</p>
  
  <blockquote>
    <p>RenderFlex children have non-zero flex but incoming height constraints are unbounded.</p>
  </blockquote>
  
  <p>When a column is in a parent that does not provide a finite height constraint, for example if it is in a vertical scrollable, it will try to shrink-wrap its children along the vertical axis. Setting a flex on a child (e.g. using Expanded) indicates that the child is to expand to fill the remaining space in the vertical direction.
  These two directives are mutually exclusive. If a parent is to shrink-wrap its child, the child cannot simultaneously expand to fit its parent.
  Consider setting mainAxisSize to MainAxisSize.min and using FlexFit.loose fits for the flexible children (using Flexible rather than Expanded). This will allow the flexible children to size themselves to less than the infinite remaining space they would otherwise be forced to take, and then will cause the RenderFlex to shrink-wrap the children rather than expanding to fit the maximum constraints provided by the parent.</p>
  
  <blockquote>
    <p>RenderBox was not laid out: RenderFlex#4c442 relayoutBoundary=up12 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
    'package:flutter/src/rendering/box.dart':
    Failed assertion: line 1681 pos 12: 'hasSize'</p>
  </blockquote>