如何在应用栏中添加资产图像作为Flutter应用程序中的操作图标？

Question

问题我试图在颤动屏幕的appbar中添加注销图像图标。我创建了一个资产文件夹并创建了目录images / icons /并在其中放置了图标。我在pubspec.yaml文件中提到过它们。我尝试在appbar中实现资产图像，但它不起作用。

码

pubspe.yaml

    name: mtrack_notifications
    description: Flutter application for MTrack Notifications 

    dependencies:
      flutter:
        sdk: flutter
      # The following adds the Cupertino Icons font to your application.
      # Use with the CupertinoIcons class for iOS style icons.
      cupertino_icons: ^0.1.2
      http: ^0.11.3+16
      shared_preferences: "^0.4.2"


    dev_dependencies:
      flutter_test:
        sdk: flutter


    # For information on the generic Dart part of this file, see the
    # following page: https://www.dartlang.org/tools/pub/pubspec

    # The following section is specific to 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/a_dot_burr.jpeg
      #  - images/a_dot_ham.jpeg
      assets:
      - assets/images/icons/like.png
      - assets/images/icons/logout.png
      # An image asset can refer to one or more resolution-specific "variants", see
      # https://flutter.io/assets-and-images/#resolution-aware.

      # For details regarding adding assets from package dependencies, see
      # https://flutter.io/assets-and-images/#from-packages

      # To add custom fonts to your application, add a fonts section here,
      # in this "flutter" section. Each entry in this list should have a
      # "family" key with the font family name, and a "fonts" key with a
      # list giving the asset and other descriptors for the font. For
      # example:
      # fonts:
      #   - family: Schyler
      #     fonts:
      #       - asset: fonts/Schyler-Regular.ttf
      #       - asset: fonts/Schyler-Italic.ttf
      #         style: italic
      #   - family: Trajan Pro
      #     fonts:
      #       - asset: fonts/TrajanPro.ttf
      #       - asset: fonts/TrajanPro_Bold.ttf
      #         weight: 700
      #
      # For details regarding fonts from package dependencies,
      # see https://flutter.io/custom-fonts/#from-packages

Click to see the IDE screenshot here

Appbar代码

    @override
      Widget build(BuildContext context) {
        //build a form widget using the form key we created above
        return new Scaffold(
          appBar: new AppBar(
            title: new Text(StringRef.appName),
            actions: [

          new Center(
          child:new Text(
            userName,
            textScaleFactor: 1.5,
            style: new TextStyle(
              fontSize: 12.0,
              color: Colors.white,
            ),
          )),
          new IconButton(
            icon: new Icon(Icons.close),
            tooltip: 'Closes application',
            onPressed: () => exit(0),
          ),

          new IconButton(
            icon: new Image.asset('images/icons/logout.png'),
            tooltip: 'Closes application',
            onPressed: () => exit(0),
          ),

            ],
          ),

Answer 1

问题出在您提供给IconButton的路径中。

它应该是这样的。

new IconButton(
            icon: new Image.asset('assets/images/icons/logout.png'),
            tooltip: 'Closes application',
            onPressed: () => exit(0),
          )

Answer 2

根据Flutter Documentation，您需要包含资产的pubspec.yaml中指定的完整路径以加载它：

Image.asset('assets/images/icons/logout.png')

Answer 3

如果您将图像放在文件夹文件夹中，请不要尝试在pubspec.yaml中注册所有图像，然后您应该注册所有文件夹。像这样

你把一个图像：hero.png放在文件夹资产中的图像内。资产>图片> hero.png

然后你应该在'pubspec.yaml'中写下：'flutter：assets：-Assets / Images / hero.png'