sliver_tools 0.1.7

Flutter Android iOS web

A set of useful sliver tools that are missing from the flutter framework

sliver_tools #

pub package

A set of useful sliver tools that are missing from the flutter framework.

Here is a taste what you can make using this package

Demo

The structure of this app:

class Section extends State {
  @override
  Widget build(BuildContext context) {
    return MultiSliver(
      pushPinnedChildren: true,
      children: <Widget>[
        SliverPersistentHeader(
          pinned: true,
          ...
        ),
        if (!infinite)
          SliverAnimatedPaintExtent(
            child: SliverList(...),
          )
        else
          SliverList(...),
      ],
    );
  }
}

class NewsPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CustomScrollView(
      slivers: <Widget>[
        Section(infinite: false),
        Section(infinite: true),
      ],
    );
  }
}

MultiSliver #

The MultiSliver widget allows for grouping of multiple slivers together such that they can be returned as a single widget. For instance when one wants to wrap a few slivers with some padding or an inherited widget.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiSliver(
      pushPinnedChildren: false, // defaults to false
      children: <Widget>[
        SliverPersistentHeader(...),
        SliverList(...),
      ],
    );
  }
}

The pushPinnedChildren parameter allows for achieving a 'sticky header' effect by simply using pinned SliverPersistentHeader widgets (or any custom sliver that paints beyond its layoutExtent).

SliverStack #

The SliverStack widget allows for stacking of both slivers and box widgets. This can be useful for adding some decoration to a sliver. Which is what some of the other widgets in this package use to get their desired effects.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverStack(
      insetOnOverlap: false, // defaults to false
      children: <Widget>[
        SliverPositioned.fill(
          child: Container(
            decoration: BoxDecoration(
              color: Colors.white,
              boxShadow: const <BoxShadow>[
                BoxShadow(
                  offset: Offset(0, 4),
                  blurRadius: 8,
                  color: Colors.black26,
                )
              ],
              borderRadius: BorderRadius.circular(8),
            ),
          ),
        )
        SliverList(...),
      ],
    );
  }
}

The insetOnOverlap handles whether the positioned children should be inset (made smaller) when the sliver has overlap from a previous sliver.

SliverClip #

The SliverClip widget will add a clip around its child from the child's paintOrigin to its paintExtent. This is very useful and most likely what you want when using a pinned SliverPersistentHeader as child of the stack.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverClip(
      clipOverlap: true, // defaults to true
      child: SliverList(...),
    );
  }
}

The clipOverlap parameter allows for configuring whether any overlap with the previous child should be clipped. This can be useful when one has a SliverPersitentHeader above a SliverList and does not want to give the header an opaque background but also prevent the list from drawing underneath the header.

SliverAnimatedPaintExtent #

The SliverAnimatedPaintExtent widget allows for having a smooth transition when a sliver changes the space it will occupy inside the viewport. For instance when using a SliverList with a button below it that loads the next few items.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverAnimatedPaintExtent(
      duration: const Duration(milliseconds: 150),
      child: SliverList(...),
    );
  }
}

SliverAnimatedSwitcher #

The SliverAnimatedSwitcher widget is simply a pre-configured AnimatedSwitcher widget. If one needs more options than supplied by this widget a regular AnimatedSwitcher can be used by giving it the defaultLayoutBuilder and defaultTransitionBuilder of SliverAnimatedSwitcher.

SliverCrossAxisConstrained #

The SliverCrossAxisConstrained widget allows for limiting the cross axis extent of a sliver to a maximum value given by the maxCrossAxisExtent. For instance a long list of text items on an iPad would be too wide to read so one can wrap the SliverList in a SliverCrossAxisConstrained and limit its width to something more reasonable.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverCrossAxisConstrained(
      maxCrossAxisExtent: 700,
      child: SliverList(...),
    );
  }
}

SliverCrossAxisPadded #

The SliverCrossAxisPadded widget allows for adding padding to the cross axis of a sliver. This can be done either by passing a paddingStart and/or paddingEnd or by using the symmetric constructor which takes a single padding value. When using paddingStart and paddingEnd in a vertical sliver it will depend on the TextDirection whether start is left or right.

Example #

class WidgetThatReturnsASliver extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SliverCrossAxisPadded(
      paddingStart: 24,
      paddingEnd: 48,
      textDirection: TextDirection.ltr, // optional, defaults to the Directionality specified by the context
      child: SliverList(...),
    );
  }
}

SliverPinnedHeader #

The SliverPinnedHeader widget allows for easily making a pinned header. It will size itself to the size of the child and when it reaches the leading edge of the viewport stay there instead of scrolling off the screen.

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Publisher

pietervanloon.com

A set of useful sliver tools that are missing from the flutter framework

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Documentation

API reference

License

MIT (LICENSE)

Dependencies

flutter

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