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Flutter 我在颤振中发现了类型错误。我该怎么办?我被困在这里了_Flutter_User Interface_Visual Studio Code_Project_User Experience - Fatal编程技术网

Flutter 我在颤振中发现了类型错误。我该怎么办?我被困在这里了

Flutter 我在颤振中发现了类型错误。我该怎么办?我被困在这里了,flutter,user-interface,visual-studio-code,project,user-experience,Flutter,User Interface,Visual Studio Code,Project,User Experience,如何解决颤振中的FindancestorStateof类型错误?我无法使用这些代码导航到其他页面。这个代码有什么问题 我得到的错误是 对null调用了方法“findAncestorStateOfType”。 收件人:空 已尝试调用:findAncestorStateOfType() 我的代码是: // entry point for the app, // the => operator is shorthand for {} when there is only one line of

如何解决颤振中的FindancestorStateof类型错误?我无法使用这些代码导航到其他页面。这个代码有什么问题

我得到的错误是 对null调用了方法“findAncestorStateOfType”。 收件人:空 已尝试调用:findAncestorStateOfType()

我的代码是:


// entry point for the app,
// the => operator is shorthand for {} when there is only one line of code
void main() {
  runApp(MaterialApp(
    home: HomeRoute(),
  ));
}

// the root widget of our application
class HomeRoute extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Color(0xFFFAAC98),
        appBar: AppBar(
          backgroundColor: Color(0xFFFAAC98),
        ),
        body: myLayoutWidget(),
      ),
    );
  }
}

// replace this method with code in the examples below
Widget myLayoutWidget() {
  return Container(
    child: Column(
      mainAxisAlignment: MainAxisAlignment.start,
      children: <Widget>[
        Padding(
          padding: const EdgeInsets.all(8.0),
          child: Container(
            width: 300,
            height: 50,
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(30.0),
              color: const Color(0xff89C5CC),
            ),
            child: Center(
              child: new Text(
                'Gram Panchayat App',
                style: TextStyle(
                    fontSize: 27,
                    fontWeight: FontWeight.bold,
                    color: Color(0xFF2F3676)),
              ),
            ),
          ),
        ),
        Row(
          children: [
            Padding(
              padding: const EdgeInsets.only(right: 18.0, top: 18.0),
              child: Image.asset(
                'assets/images/human1.png',
                width: 150,
                height: 150,
              ),
            ),
            Padding(
              padding: const EdgeInsets.only(left: 58.0),
              child: elevatedButton(),
            ),
          ],
        ),
        new Row(
          children: [
            Padding(
              padding: const EdgeInsets.only(left: 28.0),
              child: elevatedButton1(),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 58.0, left: 68.0),
              child: new Image.asset(
                'assets/images/human2.png',
                width: 200,
                height: 170,
              ),
            ),
          ],
        ),
        Padding(
          padding: const EdgeInsets.only(left: 60.0),
          child: Row(children: [
            new Image.asset(
              'assets/images/img3.png',
              width: 180,
              height: 80,
            ),
          ]),
        )
      ],
    ),
  );
}

ElevatedButton elevatedButton() => ElevatedButton(
      onPressed: () {
        BuildContext context;
        Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => SecondRoute()),
        );
      },
      child: Text('Citizen'),
    );

ElevatedButton elevatedButton1() =>
    ElevatedButton(onPressed: () {}, child: Text('Staff'));

class SecondRoute extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Second Route"),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: () {
            Navigator.pop(context);
          },
          child: Text('Go back!'),
        ),
      ),
    );
  }
}```

*Please help me I am stuck. I have gone through many sites but couldnt find what is wrong and the solution also.*

//应用程序的入口点,
//当只有一行代码时,=>运算符是{}的简写
void main(){
runApp(材料应用程序)(
主页:HomeRoute(),
));
}
//我们应用程序的根部件
类HomeRoute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(
家:脚手架(
背景颜色:颜色(0xFFFAAC98),
appBar:appBar(
背景颜色:颜色(0xFFFAAC98),
),
正文:MyLayouWidget(),
),
);
}
}
//用下面示例中的代码替换此方法
小部件MyLayouWidget(){
返回容器(
子:列(
mainAxisAlignment:mainAxisAlignment.start,
儿童:[
填充物(
填充:常数边集全部(8.0),
子:容器(
宽度:300,
身高:50,
装饰:盒子装饰(
边界半径:边界半径。圆形(30.0),
颜色:常量颜色(0xff89C5CC),
),
儿童:中心(
儿童:新文本(
“Gram Panchayat应用程序”,
样式:TextStyle(
尺寸:27,
fontWeight:fontWeight.bold,
颜色:颜色(0xFF2F3676)),
),
),
),
),
划船(
儿童:[
填充物(
填充:仅限常量边集(右侧:18.0,顶部:18.0),
子:Image.asset(
“assets/images/human1.png”,
宽度:150,
身高:150,
),
),
填充物(
填充:仅限常量边集(左:58.0),
子项:elevatedButton(),
),
],
),
新行(
儿童:[
填充物(
填充:仅限常量边集(左:28.0),
子项:提升按钮1(),
),
填充物(
填充:仅限常量边集(顶部:58.0,左侧:68.0),
子:新建Image.asset(
“assets/images/human2.png”,
宽度:200,
身高:170,
),
),
],
),
填充物(
填充:仅限常量边集(左:60.0),
子对象:行(子对象:[
新形象资产(
“assets/images/img3.png”,
宽度:180,
身高:80,
),
]),
)
],
),
);
}
ElevatedButton ElevatedButton()=>ElevatedButton(
已按下:(){
构建语境;
导航器。推(
上下文
MaterialPartnerRoute(生成器:(上下文)=>SecondRoute()),
);
},
child:Text('Citizen'),
);
LevatedButton LevatedButton1()=>
提升按钮(按下时:(){},子项:Text('Staff');
类SecondRoute扩展了无状态小部件{
@凌驾
小部件构建(构建上下文){
返回脚手架(
appBar:appBar(
标题:文本(“第二条路线”),
),
正文:中(
儿童:升降按钮(
已按下:(){
Navigator.pop(上下文);
},
child:Text('Go back!'),
),
),
);
}
}```
*请帮帮我,我卡住了。我浏览了很多网站,但都找不到问题所在,也找不到解决办法*
MyLayouWidget()
放在
HomeRoute
类中

和使用

Navigator.of(context,rootNavigator:true).pop();
而不是

 Navigator.pop(context);