ListView inside Column causes 'Vertical viewport was given unbounded height'

问题

I am new to flutter and having trouble with layouts.

I want something like this:

A sticky header and a scroll view below it. I thought of using Column widget with two children - first being the header and second being the ListView.

Here is my code

 Widget build(BuildContext context) {
 return Material(
   elevation: 8.0,
   child: Column(
     crossAxisAlignment: CrossAxisAlignment.start,
     children: <Widget>[
       Padding(
         padding: const EdgeInsets.all(16.0),
         child: Text(
           title,
           style:
               Theme.of(context).textTheme.subhead.copyWith(fontSize: 18.0),
           textAlign: TextAlign.left,
         ),
       ),
       Divider(height: 4.0),
       ListView.builder(itemBuilder: (context, i) {
         return ListTile(
           title: Text("Title $i"),
           subtitle: Text("Subtitle $i"),
         );
       }),
     ],
   ),
 );
}

I am getting the following error for it.

I/flutter ( 5725): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 5725): The following assertion was thrown during performResize():
I/flutter ( 5725): Vertical viewport was given unbounded height.
I/flutter ( 5725): Viewports expand in the scrolling direction to fill their container.In this case, a vertical
I/flutter ( 5725): viewport was given an unlimited amount of vertical space in which to expand. This situation
I/flutter ( 5725): typically happens when a scrollable widget is nested inside another scrollable widget.
I/flutter ( 5725): If this widget is always nested in a scrollable widget there is no need to use a viewport because
I/flutter ( 5725): there will always be enough vertical space for the children. In this case, consider using a Column
I/flutter ( 5725): instead. Otherwise, consider using the "shrinkWrap" property (or a ShrinkWrappingViewport) to size
I/flutter ( 5725): the height of the viewport to the sum of the heights of its children.

I added made shrinkWrap of ListView true as mentioned in the message, but that didn't work either.

The parent of this layout is a stack containing various such layout-pages, all of this layout pages being offstage expect the one user has selected.

What am I doing wrong?

回答1:

Try wrapping your ListView.builder with a Flexible or Expanded widget:

Flexible(
            child: ListView.builder(
              itemBuilder: (context, i) {
                return ListTile(
                  title: Text("Title $i"),
                  subtitle: Text("Subtitle $i"),
                );
              },
            ),
          ),

来源：https://stackoverflow.com/questions/51681763/listview-inside-column-causes-vertical-viewport-was-given-unbounded-height