这是我的pubspec.yaml

flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
uses-material-design: true

  # To add assets to your application, add an assets section, like this:
assets:
      - images/img_rectangle1.jpg

我已经建立了一个assets文件夹，并将其包含在my.png图片中;但是，我在使用小部件时遇到了困难。

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: const Text("Korean vocabulary related to traits"),
      centerTitle: false,
      backgroundColor:  const Color(0xFFEC74C8),
    ),
    body: Row(
      children: [
        Expanded(
            child: ListView.builder(
              itemCount: koreanNameList.length,
              itemBuilder: (context, index) {
                KoreanItem item = koreanNameList[index];
                return Draggable<KoreanItem>(
                    data: item,
                    dragAnchorStrategy: pointerDragAnchorStrategy,
                    feedback: KoreanNameCard(item: item),
                    child: KoreanNameCard(item: item));
              },
            )),
        Expanded(
            child: ListView.builder(
              itemCount: englishanswers.length,
              itemBuilder: (context, index) {
                return buildEnglishanswerColumn(englishanswers[index]);
              },
            )),
      ],
    ),
  );
}

那么，存放背景图片的容器应该放在哪里呢？
我试过用

AssetImage

但它没有显示在我的应用程序上。