title: Flutter: Fixed widget and listview in one page
body: <p>I make a project in Flutter where I have a Dropdownmenu and under the menu, I will have a listview but I got an error. But when I have only the listview or the Dropdownmenu then it works but not both.</p>
  
  <p>Here is the code:</p>
  
  <pre><code>class _ListViewRound extends State&lt;ListViewRound&gt; {
    String dropdownValue = 'Runde 1';
  
    @override
    Widget build(BuildContext context) {
      return Column(
        children: &lt;Widget&gt;[
          DropdownButton&lt;String&gt;(
            value: dropdownValue,
            onChanged: (String newValue) {
              setState(() {
                dropdownValue = newValue;
              });
            },
            items: &lt;String&gt;['Runde 1','Runde 2','Runde 3','Runde 4','Runde 5','Runde 6','Runde 7'] 
                .map&lt;DropdownMenuItem&lt;String&gt;&gt;((String value) {
              return DropdownMenuItem&lt;String&gt;(
                value: value,
                child: Text(value),
              );
            }).toList(),
          ),
          Container(
            child: ListView.builder(
              itemCount: playID.length,
              itemBuilder: (BuildContext context, int index) {
                return ListTile(
                  title: Text(firstPlayer[index] + '-' + secondPlayer[index]),
                  onTap: () {
                    showSnackBar(context, playID[index]);
                  },
                );
              },
            ),
          ),
        ],
      );
    }
  </code></pre>
  
  <p>And this is the error:</p>
  
  <pre><code>I/flutter (24219): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
  I/flutter (24219): The following assertion was thrown during performResize():
  I/flutter (24219): Vertical viewport was given unbounded height.
  I/flutter (24219): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
  I/flutter (24219): viewport was given an unlimited amount of vertical space in which to expand. This situation
  I/flutter (24219): typically happens when a scrollable widget is nested inside another scrollable widget.
  I/flutter (24219): If this widget is always nested in a scrollable widget there is no need to use a viewport because
  I/flutter (24219): there will always be enough vertical space for the children. In this case, consider using a Column
  I/flutter (24219): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
  I/flutter (24219): the height of the viewport to the sum of the heights of its children.
  I/flutter (24219): When the exception was thrown, this was the stack:
  </code></pre>