dart - Flutter Stepper 卧式不工作

Question

我在将步进器类型从垂直更改为水平时遇到问题。

这是我的代码:

body: new ListView.builder(
    itemCount: data == null ? 0 : 5,
    itemBuilder: (BuildContext context, int index) {
      return new Card(
          //child: new Text(data[index]["title"]),
          child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Stepper(
          steps: my_steps,
          type: StepperType.horizontal,
          controlsBuilder: (BuildContext context,
              {VoidCallback onStepContinue, VoidCallback onStepCancel}) {
            return Row(
              children: <Widget>[
                Container(
                  child: null,
                ),
                Container(
                  child: null,
                ),
              ],
            );
          },
          //type: StepperType.horizontal,
        ),
      ));
    },
  ),

在我取消对类型的注释后，我得到了这个错误:

I/flutter (10148): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════ I/flutter (10148): The following assertion was thrown during performLayout(): I/flutter (10148): RenderFlex children have non-zero flex but incoming height constraints are unbounded. I/flutter (10148): When a column is in a parent that does not provide a finite height constraint, for example if it is I/flutter (10148): in a vertical scrollable, it will try to shrink-wrap its children along the vertical axis. Setting a I/flutter (10148): flex on a child (e.g. using Expanded) indicates that the child is to expand to fill the remaining I/flutter (10148): space in the vertical direction.

Answer 1

您的 ListView 的高度是无限的，所以它不知道为每个子项(一个 Stepper)使用多少空间。给它一些限制，例如每个限制的最小高度，你应该没问题。

 (...)
 ConstrainedBox(
              constraints: BoxConstraints.tightFor(height: 200.0),
              child: Stepper(
                steps: my_steps(),
                type: StepperType.horizontal,
 (...)