DraggableScrollableSheet中的Listview不能滚动显示 [英] Listview inside DraggableScrollableSheet not scrolling in flutter

问题描述

我被设计成非常沉重的嵌套设计，如下所示，当我的列表扩展到listview时，问题似乎并没有滚动，这是什么原因，底页被扩展了，但其中没有关注于listview，如果我通过触摸运行时间"文本进行滚动，它开始滚动，但是当它向上时，我无法将其向下滑动.

I am designed very heavy nested design like below, the issue when my list expands the listview doesn't seems to be scrolling what is the reason for this, the bottomsheet gets expanded but there is no focus on listview inside it, if i scrolls by touching the 'Operational Hours' text it starts scrolling but when it goes upwards i can't slide it down.

_showDialog(BuildContext context) {
    print("_showDialog");
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (BuildContext context) {
        return DraggableScrollableSheet(
          expand: false,
          builder: (context, scrollController) {
            return Container(
              child: Stack(
                children: <Widget>[
                  Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: <Widget>[
                      Align(
                          alignment: Alignment.topCenter,
                          child: Container(
                              margin: EdgeInsets.symmetric(vertical: 8),
                              height: 8.0,
                              width: 70.0,
                              decoration: BoxDecoration(
                                  color: Colors.grey[400],
                                  borderRadius: BorderRadius.circular(10.0)))),
                      SizedBox(height: 16),
                      Padding(
                        padding: const EdgeInsets.symmetric(horizontal: 24),
                        child: Text('Operational Hours',
                            style: TextStyle(
                                fontWeight: FontWeight.bold,
                                fontSize: widget.isTab(context)
                                    ? TabTextStyles.mediumText
                                        .copyWith()
                                        .fontSize
                                    : PhoneTextStyles.mediumText
                                        .copyWith()
                                        .fontSize)),
                      ),
                    ],
                  ),
                  ListView(
                    controller: scrollController,
                    children: <Widget>[
                      SizedBox(height: 54.0),
                      Padding(
                        padding: const EdgeInsets.symmetric(horizontal: 24),
                        child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: <Widget>[
                              SizedBox(height: 20.0),
                              Text('Select days to add hours',
                                  style: widget.isTab(context)
                                      ? TabTextStyles.mediumText.copyWith()
                                      : PhoneTextStyles.mediumText.copyWith()),
                            ]),
                      ),
                      DaysList()
                    ],
                  ),
                ],
              ),
              decoration: BoxDecoration(
                shape: BoxShape.rectangle,
                color: Theme.of(context).backgroundColor,
                borderRadius: BorderRadius.only(
                  topLeft: Radius.circular(24.0),
                  topRight: Radius.circular(24.0),
                ),
              ),
            );
          },
        );
      },
    );
  }

推荐答案

您正在犯几个错误.首先，将始终在顶部可见的小部件放在Column中，然后将DaysList包裹在Expanded中，然后将ScrollController传递给它.

There are couple of mistakes you're making. First, put widgets in Column that are always going to be visible at top, second wrap your DaysList in Expanded and pass ScrollController to it.

这是您的方法:

void _showDialog(BuildContext context) {
  showModalBottomSheet(
    context: context,
    isScrollControlled: true,
    builder: (BuildContext context) {
      return DraggableScrollableSheet(
        expand: false,
        builder: (context, scrollController) {
          return Column(
            children: <Widget>[
              // Put all heading in column.
              column,
              // Wrap your DaysList in Expanded and provide scrollController to it
              Expanded(child: DaysList(controller: scrollController)),
            ],
          );
        },
      );
    },
  );
}

这是您的Column:

Widget get column {
  return Column(
    crossAxisAlignment: CrossAxisAlignment.start,
    children: <Widget>[
      Align(
        alignment: Alignment.topCenter,
        child: Container(
          margin: EdgeInsets.symmetric(vertical: 8),
          height: 8.0,
          width: 70.0,
          decoration: BoxDecoration(color: Colors.grey[400], borderRadius: BorderRadius.circular(10.0)),
        ),
      ),
      SizedBox(height: 16),
      Padding(
        padding: const EdgeInsets.symmetric(horizontal: 24),
        child: Text('Operational Hours', style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),),
      ),
      Padding(
        padding: const EdgeInsets.symmetric(horizontal: 24),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            SizedBox(height: 20.0),
            Text('Select days to add hours'),
          ],
        ),
      ),
      SizedBox(height: 16),
    ],
  );
}

这是您的DaysList的外观:

class DaysList extends StatelessWidget {
  final ScrollController controller;

  const DaysList({Key key, this.controller}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      controller: controller, // assign controller here
      itemCount: 20,
      itemBuilder: (_, index) => ListTile(title: Text("Item $index")),
    );
  }
}

输出:

这篇关于DraggableScrollableSheet中的Listview不能滚动显示的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！