Flutter - 自动调整 AlertDialog 大小以适应列表内容

Question

我需要从 rest web 服务动态加载列表城市，并让用户从警报对话框中选择一个城市。我的代码:

createDialog() {

    fetchCities().then((response) {

      showDialog(
          context: context,
          builder: (BuildContext context) {
            return AlertDialog(
              title: Text('Wybierz miasto'),
              content: Container(
                height: 200.0,
                width: 400.0,
                child: ListView.builder(
                  shrinkWrap: true,
                  itemCount: response.length,
                  itemBuilder: (BuildContext context, int index) {
                    return ListTile(
                      title: Text(response[index].name),
                      onTap: () => citySelected(response[index].id),
                    );
                  },
                ),
              ),
            );
          }
      );
    });
  }

结果 - 对话框始终为 200x400，即使只有 2 个城市可用，底部也会留下不必要的空间:

如何使对话框宽度/高度适合实际项目大小？如果我省略 height 和 width 参数，我会遇到异常并且不会显示对话框。在 native Android Java 中，我从不需要指定任何尺寸，因为对话框会自动调整自身大小以适应。

如何修复我的代码以正确调整对话框大小？注意:我不知道项目数，它是动态的。

[编辑]

按照建议，我用列包装了内容:

createDialog() {
    fetchCities().then((response) {
      showDialog(
          context: context,
          builder: (BuildContext context) {
            return AlertDialog(
              title: Text('Wybierz miasto'),
              content: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    Container(
                      child: ListView.builder(
                        shrinkWrap: true,
                        itemCount: response.length,
                        itemBuilder: (BuildContext context, int index) {
                          return ListTile(
                            title: Text(response[index].name),
                            onTap: () => citySelected(response[index].id),
                          );
                        },
                      ),
                    )
                  ]
              ),
            );
          }
      );
    });
  }

结果 - 异常:

I/flutter ( 5917): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY╞═════════════════════════════════════════════════════════ I/flutter (5917): The following assertion was thrown during performLayout():I/flutter ( 5917): RenderViewport does not support returning intrinsicdimensions. I/flutter ( 5917): Calculating the intrinsic dimensionswould require instantiating every child of the viewport, whichI/flutter ( 5917): defeats the point of viewports being lazy.

要测试的更通用的代码:

showDialog(
       context: context,
       builder: (BuildContext context) {
         return AlertDialog(
           title: Text('Select city'),
           content: Column(
               mainAxisSize: MainAxisSize.min,
               children: <Widget>[
                 Container(
                   child: ListView.builder(
                     shrinkWrap: true,
                     itemCount: 2,
                     itemBuilder: (BuildContext context, int index) {
                       return ListTile(
                         title: Text("City"),
                         onTap: () => {},
                       );
                     },
                   ),
                 )
               ]
           ),
         );
       }
   );

Answer 1

将您的 Container 包裹在 Column 中，在内容参数中，在其中设置 mainAxisSize.min，在 Column 属性中

Container(
  child: Column(
    mainAxisSize: MainAxisSize.min,
    children: [
      ...
    ],
  )
)