Flutter &引用；使用材料设计：真实；不使用pubspec.yaml中的其他资产

在我删除/注释这一行之前，我无法将任何资产（如图像、字体等）添加到我的项目应用程序中

uses-material-design: true

错误

Error detected in pubspec.yaml:
Restarted application in ٨ms.
Error on line 25, column 4: Expected a key while parsing a block mapping.
   ╷
25 │    assets:
   │    ^
   ╵
Exception: Please correct the pubspec.yaml file at .\pubspec.yaml

除了这个问题，在

pubspec.yaml

name: mi_card
description: A new Flutter application.

version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^0.1.2

dev_dependencies:
  flutter_test:
    sdk: flutter


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/

   fonts:
     - family: Pacifico
       fonts:
         - asset: fonts/Pacifico-Regular.ttf

     - family: Source Sans Pro
       fonts:
        - asset: fonts/SourceSansPro-Regular.ttf

名称：密苏里卡
描述：一个新的颤振应用。
版本：1.0.0+1
环境：
sdk:“>=2.1.0
pubspec.yaml
对缩进敏感

在
之后的文件中使用了材质设计：true
缩进一个空格，尝试删除它，它就会工作

复制此文件并尝试：

name: mi_card
description: A new Flutter application.

version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  cupertino_icons: ^0.1.2

dev_dependencies:
  flutter_test:
    sdk: flutter


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/

  fonts:
    - family: Pacifico
      fonts:
        - asset: fonts/Pacifico-Regular.ttf

    - family: Source Sans Pro
      fonts:
        - asset: fonts/SourceSansPro-Regular.ttf

名称：密苏里卡
描述：一个新的颤振应用。
版本：1.0.0+1
环境：
sdk:“>=2.1.0运行良好，谢谢，请您参考我添加了多个空格的哪一行，因为我尝试将其与我的版本进行比较，但我找不到差异，它正在删除的不是“添加空格”。。在使用材质设计后，您必须从所有行中删除两个空格：true，换句话说，使用材质设计后的行的开头：true应该对齐，如果这有助于将问题标记为已回答；）