Flutter SliverPersistentHeader is causing "bottom overflow when scroll"

Question

i have a SliverPersistentHeader that causes bottom overflowed when user scrolls the screen.

How can i fix it?

    return CustomScrollView(
      slivers: <Widget>[
        SliverPersistentHeader(
          pinned: false,
          delegate: DynamicSliverHeaderDelegate(
            maxHeight: 256,
            minHeight: 186,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.start,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                _topo(context, grupo),
                _infoGrupo(context, grupo),
              ],
            ),
          ),
        ),

        // TODO: Lista do grupo 
        SliverFillViewport(
          delegate: SliverChildListDelegate(
            [
              Container(
                padding: EdgeInsets.only(top: 100),
                color: Colors.green.withOpacity(0.2),
                child: Column(
                  children: <Widget>[
                    Text('TODO... A construir'),
                  ],
                ),
              ),
            ],
          ),
        ),
      ],
    );

// .....

class DynamicSliverHeaderDelegate extends SliverPersistentHeaderDelegate {
  final Widget child;
  final double maxHeight;
  final double minHeight;

  const DynamicSliverHeaderDelegate({
    @required this.child,
    this.maxHeight = 250,
    this.minHeight = 80,
  });

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return child;
  }

  // @override
  // bool shouldRebuild(DynamicSliverHeaderDelegate oldDelegate) => true;

  @override
  bool shouldRebuild(DynamicSliverHeaderDelegate oldDelegate) {
    return maxHeight != oldDelegate.maxHeight ||
        minHeight != oldDelegate.minHeight ||
        child != oldDelegate.child;
  }

  @override
  double get maxExtent => maxHeight;

  @override
  double get minExtent => minHeight;
}

Wemerson Guimaraes · Accepted Answer · 2020-02-21 16:30:51Z

2

Solved it by wrapping the DynamicSliverHeaderDelegate Column child with a SingleChildScrollView´ withNeverScrollableScrollPhysics` physics.

return CustomScrollView(
  slivers: <Widget>[
    SliverPersistentHeader(
      pinned: false,
      delegate: DynamicSliverHeaderDelegate(
        maxHeight: 256,
        minHeight: 186,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.start,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            _topo(context, grupo),
            _infoGrupo(context, grupo),
          ],
        ),
      ),
    ),
    // TODO: Lista do grupo 
    // ...
  ],
);

answered Feb 21, 2020 at 16:30

Wemerson Guimaraes

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2 Comments

romaneso Over a year ago

Sorry, but could you please update your code? it is missing and not showing the final result- thank you!

davejlin Over a year ago

@romaneso The author explained the solution. To be explicit, I updated the code with the fix in my answer.

John Joe · Accepted Answer · 2021-12-20 16:34:11Z

0

The complete fix is:

 return CustomScrollView(
      slivers: <Widget>[
        SliverPersistentHeader(
          pinned: false,
          delegate: DynamicSliverHeaderDelegate(
            maxHeight: 256,
            minHeight: 186,
            child: SingleChildScrollView(
              physics: const NeverScrollableScrollPhysics(),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.start,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  _topo(context, grupo),
                  _infoGrupo(context, grupo),
                ],
              ),
            ),
          ),
        ),
        // TODO: Lista do grupo
        // ...
      ],
    );
   }

edited Dec 20, 2021 at 16:34

John Joe

12.8k19 gold badges79 silver badges142 bronze badges

answered Oct 21, 2020 at 1:44

davejlin

1,11811 silver badges18 bronze badges

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