Android 颤振总成可'；在构建小部件树时，不要第一次加载

我正在Flitter中创建一个Hangman应用程序，我想在生命减少时将主图像更新为另一个。问题是，当我第一次运行应用程序时，出现以下错误：

I/flutter (21336): ══╡ EXCEPTION CAUGHT BY IMAGE RESOURCE SERVICE ╞════════════════════════════════════════════════════
I/flutter (21336): The following assertion was thrown resolving an image codec:
I/flutter (21336): Unable to load asset: assets/Hangman 10.png
I/flutter (21336): 
I/flutter (21336): When the exception was thrown, this was the stack:
I/flutter (21336): #0      PlatformAssetBundle.load (package:flutter/src/services/asset_bundle.dart:221:7)
I/flutter (21336): <asynchronous suspension>
I/flutter (21336): #1      AssetBundleImageProvider._loadAsync (package:flutter/src/painting/image_provider.dart:484:44)
I/flutter (21336): #2      AssetBundleImageProvider.load (package:flutter/src/painting/image_provider.dart:469:14) 
I/flutter (21336): #3      ImageProvider.resolve.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:flutter/src/painting/image_provider.dart:327:17)
I/flutter (21336): #4      ImageCache.putIfAbsent (package:flutter/src/painting/image_cache.dart:160:22)
I/flutter (21336): #5      ImageProvider.resolve.<anonymous closure>.<anonymous closure> (package:flutter/src/painting/image_provider.dart:325:84)
I/flutter (21336): (elided 13 frames from package dart:async)
I/flutter (21336):
I/flutter (21336): Image provider: AssetImage(bundle: null, name: "assets/Hangman 10.png")
I/flutter (21336): Image key: AssetBundleImageKey(bundle: PlatformAssetBundle#133ec(), name: "assets/Hangman 10.png",
I/flutter (21336):   scale: 1.0)
I/flutter (21336): ════════════════════════════════════════════════════════════════════════════════════════════════════

这是我的文件夹的结构

还有我的主.dart文件

import 'package:flutter/material.dart';
import 'nouns.dart';
import 'keyboard_ws.dart';

void main() => runApp(MaterialApp(home: Home()));

String word = 'wordToBeGuessed'
int lives = 10;
List<String> lettersEntered = [];


class Home extends StatefulWidget {
  @override
  HomeState createState() => HomeState();
}

String word = 'savannah';
int lives = 10;
List<String> lettersEntered = [];
List<String> wordShowList = List.filled(word.length, '_');
String displayWord = wordShowList.join(' ');

class HomeState extends State<Home> {
@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Hangman'),
        centerTitle: true,
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          Expanded(
              child: Container(
            padding: EdgeInsets.symmetric(vertical: 30, horizontal: 20),
            child: Image(
              image: AssetImage('assets/Hangman $lives.png'),
              gaplessPlayback: true,
            ),
          )),
          Container(
            child: Text(
              displayWord,
              style: TextStyle(fontSize: 30),
            ),
          ),
          Keyboard(lettersEntered, sendKey)
        ],
      ),
    );
  }
}

---

原因：您的图像名称有空格
解决方案：

当资产路径包含空间时无法加载资产

已在当前beta

v1.17.0-3.2.pre

和dev

v1.18.0-6.0.pre

中修复（但不在稳定的

v1.12.13+热修复程序中。9

）
您可以考虑切换到新版本

工作演示

完整代码

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {  
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(       
        primarySwatch: Colors.blue,       
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {     
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {    
    return Scaffold(
      appBar: AppBar(       
        title: Text(widget.title),
      ),
      body: Center(        
        child: Column(          
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(
                child: Container(
                  padding: EdgeInsets.symmetric(vertical: 30, horizontal: 20),
                  child: Image(
                    image: AssetImage('assets/images/alarm space.png'),
                    gaplessPlayback: true,
                  ),
                )),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

导入“包装：颤振/材料.省道”；
void main（）{
runApp（MyApp（））；
}
类MyApp扩展了无状态小部件{
@凌驾
小部件构建（构建上下文）{
返回材料PP(
标题：“颤振演示”，
主题：主题资料（
主样本：颜色。蓝色，
视觉密度：视觉密度。自适应平台密度，
),
主页：MyHomePage（标题：“颤振演示主页”），
);
}
}
类MyHomePage扩展StatefulWidget{
MyHomePage（{Key，this.title}）：超级（Key:Key）；
最后的字符串标题；
@凌驾
_MyHomePageState createState（）=>\u MyHomePageState（）；
}
类_MyHomePageState扩展状态{
int _计数器=0；
void _incrementCounter（）{
设置状态（（）{
_计数器++；
});
}
@凌驾
小部件生成（BuildContext上下文）{
返回脚手架(
appBar:appBar（
标题：文本（widget.title），
),
正文：中心（
子栏（
mainAxisAlignment:mainAxisAlignment.center，
儿童：[
扩大(
子：容器(
填充：边缘组。对称（垂直：30，水平：20），
孩子：图像(
图像：AssetImage（'assets/images/alarm space.png'），
无缝隙斜背：是的，
),
)),
正文(
“您已经按了这么多次按钮：”，
),
正文(
“$”计数器“，
风格：Theme.of（context）.textTheme.headline4，
),
],
),
),
浮动操作按钮：浮动操作按钮(
按下时：\ u递增计数器，
工具提示：“增量”，
子：图标（Icons.add），
),
);
}
}

您确定您的名字正确吗？请尝试“颤振清理”。

flutter:
  assets:
  - assets/

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {  
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(       
        primarySwatch: Colors.blue,       
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {     
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {    
    return Scaffold(
      appBar: AppBar(       
        title: Text(widget.title),
      ),
      body: Center(        
        child: Column(          
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Expanded(
                child: Container(
                  padding: EdgeInsets.symmetric(vertical: 30, horizontal: 20),
                  child: Image(
                    image: AssetImage('assets/images/alarm space.png'),
                    gaplessPlayback: true,
                  ),
                )),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}