错误警告Image.asset......Flutter，Dart

编程问答 2022-08-10

问题描述

我是Flutter / Dart编程的初学者，当我想将图像添加到我的应用程序时，我始终始终运行错误。我想使用小部件Image.asset来完成此操作，实际上我想我已经在pubspec.yaml中进行了所有设置，并在项目文件夹中创建了新的文件夹资产/图像，因此该文件夹与pubspec处于同一级别.yaml。起初我遇到了一些错误，例如仅一个依赖项，或者应该是一个字符串，所以我认为我已将其修复，但是从那时起，我得到了以下错误警告：

CODE main.dart：

import 'dart:ui';
import 'package:Flutter/widgets.dart';
import 'package:Flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: Scaffold(
            appBar: AppBar(
              title: Text("TEST-TEST-TEST"),//Titel AppBar
              backgroundColor: Colors.redAccent,//Farbe AppBar
            ),body: Center(
                child: Column(children: [
              Text(
                'Hello World :)',style: TextStyle(
                    fontSize: 26,fontWeight: FontWeight.bold,color: Colors.blue[800]),),Text(
                'Second Line - works ;)',style: TextStyle(
                    fontSize: 20,fontWeight: FontWeight.normal,Image.asset(
                'assets/images/pic_1.jpg'),]))));
  }
}

enter code here

CODE pubspec.yaml：

name: hello_world

environment:
  # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
  sdk: ">=2.0.0-dev.68.0 <3.0.0"



dependencies:
  Flutter:
   #sdk: Flutter 
   assets:
     - assets/images/pic_1.jpg

  


  characters: 1.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  collection: 1.14.13 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  Meta: 1.1.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  typed_data: 1.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  vector_math: 2.0.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"

dev_dependencies:
  Flutter_driver:
    sdk: Flutter
  Flutter_test:
    sdk: Flutter
  test: 1.15.2

  _fe_analyzer_shared: 5.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  analyzer: 0.39.12 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  archive: 2.0.13 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  args: 1.6.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  async: 2.4.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  boolean_selector: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  charcode: 1.1.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  clock: 1.0.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  convert: 2.1.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  coverage: 0.14.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  crypto: 2.1.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  csslib: 0.16.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  fake_async: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  file: 5.2.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  glob: 1.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  html: 0.14.0+3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  http: 0.12.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  http_multi_server: 2.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  http_parser: 3.1.4 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  intl: 0.16.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  io: 0.3.4 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  js: 0.6.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  json_rpc_2: 2.2.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  logging: 0.11.4 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  matcher: 0.12.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  mime: 0.9.6+3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  node_interop: 1.1.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  node_io: 1.1.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  node_preamble: 1.4.12 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  package_config: 1.9.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  path: 1.7.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  pedantic: 1.9.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  pool: 1.4.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  pub_semver: 1.4.4 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  shelf: 0.7.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  shelf_packages_handler: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  shelf_static: 0.2.8 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  shelf_web_socket: 0.2.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  source_map_stack_trace: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  source_maps: 0.10.9 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  source_span: 1.7.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  stack_trace: 1.9.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  stream_channel: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  string_scanner: 1.0.5 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  sync_http: 0.2.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  term_glyph: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  test_api: 0.2.17 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  test_core: 0.3.10 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  vm_service: 4.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  vm_service_client: 0.2.6+2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  watcher: 0.9.7+15 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  web_socket_channel: 1.1.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  webdriver: 2.1.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  webkit_inspection_protocol: 0.7.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"
  yaml: 2.2.1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "Flutter update-packages --force-upgrade"


# PUBSPEC CHECKSUM: f482

错误警告：

[examples / hello_world] Flutter pub get 在hello_world中运行“ Flutter pub get” ...
由于hello_world依赖于来自未知源“资产”的混乱，因此版本解析失败。 pub获取失败（1；因为hello_world取决于未知来源“资产”的波动，所以版本解析失败。） 退出代码1

解决方法

以我的拙见，您的pubspec.yaml文件的结构不太正确。尝试在“ flutter”部分下声明资产（您似乎在“ dependencies”部分下，该内容解释了错误消息，因为hello_world取决于未知来源“资产”的漂移）：

name: hello_world
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:
  uses-material-design: true
  assets:
    - assets/images/pic_1.jpg
,

您的pubspec.yaml片段（错误）

StreamResource res = new StreamResource("10041328370.pdf",() -> 
    new FileInputStream(file));

正确的方法：

dependencies:
  flutter:
   #sdk: flutter 
   assets:
     - assets/images/pic_1.jpg

当您要宣布波动资产时

assetsassetsassetsdartimageimageimage