sliver_sticky_collapsable_panel

sliver_sticky_collapsable_panel

A Sliver implementation of sticky collapsable panel, with a box header rebuild on status and a sliver child as panel content.

Snap Shot

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Features

• Relying solely on the Flutter framework itself, no any other dependencies.
• Pure Dart implementation, running on any platform who supports Flutter.
• Command style support for expand/collpase the panel.(it's still compatible with declarative style)
• Accept one box child as header and one sliver child as panel content.
• Header can overlap panel content (useful for sticky side header for example).
• Notify and rebuild the header when status changed (scroll outside the viewport for example).
• Support not sticky headers (with sticky: false parameter).
• Support a controller which notifies the scroll offset of the current sticky header.
• Support click the header to collapse the panel, or disable collapse (with disableCollapsable = true parameter in panelController).
• Support iOS style sticky header, just like iOS's system contact app (with iOSStyleSticky = true parameter).
• Support add padding for sliver child (with paddingBeforeCollapse parameter).
• Support add padding after the header even the panel collapsed (with paddingAfterCollapse parameter).

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Getting started

• In the pubspec.yaml of your flutter project, add the following dependency:

  dependencies:
    sliver_sticky_collapsable_panel: ^5.0.1
  

• In your library add the following import:

  import 'package:sliver_sticky_collapsable_panel/sliver_sticky_collapsable_panel.dart';
  

• In your code, use the sliver like this:

  CustomScrollView(
    controller: _scrollController,
    slivers: [
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_1'),
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_2'),
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      ...,
    ],
  );
  

• For simple right side header arrow hint ^, you can build with widget in flutter framework like AnimatedRotation:

  SliverStickyCollapsablePanel(
    scrollController: _scrollController,
    panelController: StickyCollapsablePanelController(key:'key_1'),
    headerBuilder: (context, status) => Container(
      width: double.infinity,
      height: 48,
      child: Stack(
        children: [
          Text("your title, or any other box widget you like"),
          Align(
            alignment: Alignment.centerRight,
            child: AnimatedRotation(
              duration: const Duration(milliseconds: 0),
              turns: status.isExpanded ? 0 : 0.5,
              child: const Icon(Icons.expand_more),
            ),
          ), 
        ],
      ),
    ),
    sliverPanel: SliverList.list(children: [...]),
  ),
  

---

More Advanced Feature:

• You can disable collapse for any sliver you wanted, just add disableCollapsable = true.

  CustomScrollView(
    controller: _scrollController,
    slivers: [
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_1',disableCollapsable: true),
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      ...,
    ],
  );
  

---

• You can enable iOS style sticky header, just like the system's contact app with just one parameter iOSStyleSticky = true.

  CustomScrollView(
    controller: _scrollController,
    slivers: [
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_1'),
        iOSStyleSticky: true,
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      ...,
    ],
  );
  

  

---

• You can add padding for sliver child (with paddingBeforeCollapse), even if the panel is collapsed, the padding still work between headers with paddingAfterCollapse.

  CustomScrollView(
    controller: _scrollController,
    slivers: [
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_1'),
        paddingBeforeCollapse: const EdgeInsets.all(16),
        paddingAfterCollapse: const EdgeInsets.only(bottom: 10),
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      ...,
    ],
  );
  

  

---

• You can animate collapse/expand with only one parameter: panelAnimationDuration

  CustomScrollView(
    controller: _scrollController,
    slivers: [
      SliverStickyCollapsablePanel(
        scrollController: _scrollController,
        panelController: StickyCollapsablePanelController(key:'key_1'),
        panelAnimationDuration: Duration(milliseconds: 300),
        paddingBeforeCollapse: const EdgeInsets.all(16),
        paddingAfterCollapse: const EdgeInsets.only(bottom: 10),
        headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
        sliverPanel: SliverList.list(children: [...]),
      ),
      ...,
    ],
  );
  

---

Performance configuration

• You can use optional parameter headerSize to speed up the layout process when the size not change
  • if your header size maybe change, just keep this parameter null (which is the default)

    CustomScrollView(
      controller: _scrollController,
      slivers: [
        SliverStickyCollapsablePanel(
          scrollController: _scrollController,
          panelController: StickyCollapsablePanelController(key:'key_1'),
          iOSStyleSticky: true,
          headerBuilder: (context, status) => SizedBox.fromSize(size: Size.fromHeight(48)),
          headerSize: Size(MediaQuery.of(context).size.width, 48),
          sliverPanel: SliverList.list(children: [...]),
        ),
        ...,
      ],
    );
    

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Thanks

• Thanks to letsar with it's flutter_sticky_header which provide solid foundation and inspire me for this project.