颤振:如何使用DraggableScrollableActuator.reset和来自DraggableScrollableSheet的ScrollController作为嵌套列表？

Question

我得到了这个错误。

The following assertion was thrown building _InheritedResetNotifier(dirty):
flutter: ScrollController attached to multiple scroll views.
flutter: 'package:flutter/src/widgets/scroll_controller.dart':
flutter: Failed assertion: line 111 pos 12: '_positions.length == 1'

看来，我既可以将DraggableScrollableSheet的ScrollController附加到嵌套列表，也可以使用DraggableScrollableActuator.reset(context)重置范围。我不明白为什么我不能两者兼得。这是个虫子吗？周围有工作吗?还是其他方法？

这是我的代码：

class InterfaceSelector extends StatefulWidget {
  @override
  InterfaceSelectorState createState() => InterfaceSelectorState();
}

class InterfaceSelectorState extends State<InterfaceSelector> {
  double initialChildSize = 0.5;
  double minChildSize = 0.5;
  double maxChildSize = 0.7;

  @override
  Widget build(BuildContext context) {
    return DraggableScrollableActuator(
      child: DraggableScrollableSheet(
        initialChildSize: initialChildSize,
        minChildSize: minChildSize,
        maxChildSize: maxChildSize,
        builder: (BuildContext ctx, ScrollController scrollController) {
          return SingleChildScrollView(
            controller: scrollController,
            child: Container(
              height: MediaQuery.of(context).size.longestSide * .7,
              color: Theme.of(ctx).primaryColor,
              child: DefaultTabController(
                length: 4,
                child: Column(
                  children: <Widget>[
                    Material(
                      color: Theme.of(ctx).accentColor,
                      child: TabBar(
                        tabs: [
                          Tab(text: "One"),
                          Tab(text: "Two"),
                          Tab(text: "Three"),
                          Tab(text: "Four"),
                        ],
                      ),
                    ),
                    Expanded(
                      child: TabBarView(
                        children: [
                          One(),
                          Two(),
                          Three(scrollController),
                          Four(),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ),
          );
        },
      ),
    );
  }
}

class Three extends StatefulWidget {
  ScrollController scrollController;
  Three(this.scrollController);
  @override
  _ThreeState createState() => _ThreeState();
}

class _ThreeState extends State<Three> with AutomaticKeepAliveClientMixin {
  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    Stuff stuff = Provider.of<Stuff>(context);
    return Column(
      children: <Widget>[
        MaterialButton(onPressed: () {
          DraggableScrollableActuator.reset(context);
        }),
        Expanded(
          child: GridView.builder(
            controller: widget.scrollController,
            padding: const EdgeInsets.all(10),
            itemCount: stuff.all.length,
            itemBuilder: (ctx, i) => ChangeNotifierProvider.value(
              value: stuff.all[i],
              key: UniqueKey(),
              child: StuffCard(i, stuff.all[i], stuff),
            ),
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 3,
              crossAxisSpacing: 10,
              mainAxisSpacing: 10,
            ),
          ),
        ),
      ],
    );
  }
}

Answer 1

您的GridView不需要滚动-滚动是由您的SingleChildScrollView提供的。不要将scrollController传递给GridView，而是在网格构建器中设置physics: NeverScrollableScrollPhysics(),：

GridView.builder(
        physics: NeverScrollableScrollPhysics(),
        padding: const EdgeInsets.all(10),
        itemCount: stuff.all.length,
        itemBuilder: (ctx, i) => ChangeNotifierProvider.value(
          value: stuff.all[i],
          key: UniqueKey(),
          child: StuffCard(i, stuff.all[i], stuff),
        ),
        gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 3,
          crossAxisSpacing: 10,
          mainAxisSpacing: 10,
        ),
      ),