如何解决错误警告Image.asset......Flutter,Dart
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
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