Question

我正试图与供应商合作，但我不断收到此错误：

The following ProviderNotFoundException was thrown building Login(dirty, state: _LoginState#42a76):
I/flutter ( 8335): Error: Could not find the correct Provider<CRUDModel> above this Login Widget
I/flutter ( 8335): 
I/flutter ( 8335): To fix, please:
I/flutter ( 8335): 
I/flutter ( 8335):   * Ensure the Provider<CRUDModel> is an ancestor to this Login Widget
I/flutter ( 8335):   * Provide types to Provider<CRUDModel>
I/flutter ( 8335):   * Provide types to Consumer<CRUDModel>
I/flutter ( 8335):   * Provide types to Provider.of<CRUDModel>()
I/flutter ( 8335):   * Ensure the correct `context` is being used.
I/flutter ( 8335): 
I/flutter ( 8335): If none of these solutions work, please file a bug at:
I/flutter ( 8335): https://github.com/rrousselGit/provider/issues

我不知道到底是什么问题。我的应用程序中有一个初始屏幕，这使我无法在主类中添加提供程序，因此我将其移至滑块页面：此类包含登录和注册按钮（这是我添加提供程序的位置）这是我的滑块类

class _SliderScreenState extends State<SliderScreen>{
  int _current = 0;
  List<SliderModel> sliderList = []...;

  @override
  Widget build(BuildContext context) {
    final CarouselSlider coverScreenExample = CarouselSlider(... );

    return
      Scaffold(
          backgroundColor: Color(0xffE5E5E5),
          body:
          Column(
            children: <Widget>[
              Expanded(
                flex: 1,
                child: coverScreenExample,
              ),
              Padding(
                padding: EdgeInsets.only(left: 34, right: 34,bottom: 100),
                child: Row(
                  children: <Widget>[
                    Expanded(
                        flex:1,
                        child:   CustomButton(
                            text:'Login',
                            textColor:accentColor,
                            fillColor: Colors.white,
                            height: 49,
                            function: (){
                              Navigator.pushReplacement(context,MaterialPageRoute(
                                  builder: (context){
                                    return  **Provider<CRUDModel>.value(
                                      value: CRUDModel(),
                                      child:** Login() ,
                                    );
                                  }
                              ));
                              // Navigator.pushNamed(context, '/login');
                            }
                        )
                    ),
                    SizedBox(width: 61,),
                    Expanded(
                        flex: 1,
                        child: CustomButton(
                            text:'Register',
                            textColor: Colors.white,
                            height: 49,
                            fillColor:accentColor,
                            function: (){
                              Navigator.pushReplacement(context, MaterialPageRoute(builder: (context)=>Registeration()));
                            })
                    ),

                  ],
                )   ,) ,
            ],
          )

      );
  }

  List<T> map<T>(List list, Function handler) {
    List<T> result = [];
    for (var i = 0; i < list.length; i++) {
      result.add(handler(i, list[i]));
    }
    return result;
  }
}

问题是，每当我单击登录按钮时，都会收到我在屏幕和日志上方均显示的错误消息，但是如果我重新加载错误页面，则会看到我的登录屏幕。

这是我的CRUDModel类

class CRUDModel extends ChangeNotifier{

  API _api = locator<API>();

  Future signUp( BuildContext context, SignUpModel data) async{
    var result ;
    _api.path= (BASE_URL+"signup");
    Response v = await _api.postDetails(data.toJson());

    final responseJson = json.decode(v.body);
    final int statusCode =responseJson.statusCode;

    if(statusCode < 200 || statusCode > 400 ||json == null){
      result = throw new Exception("SignUP:: Error while fetching data");
    }
    else if(statusCode == 200){
      result = SignUpModel.fromJson(json.decode(responseJson));
      Navigator.push(context, MaterialPageRoute(builder: (context)=> Login()));
    }
    return result;
  }

  Future login( BuildContext context, LoginModel data) async{
    var result ;
    _api.path = BASE_URL+"login";
    Response v = await _api.postDetails(data.toJson());

    final responseJson = json.decode(v.body);
    final int statusCode =responseJson.statusCode;

    if(statusCode < 200 || statusCode > 400 ||json == null){
      result = throw new Exception("SignUP:: Error while fetching data");
    }
    else if(statusCode == 200){
      result = SignUpModel.fromJson(json.decode(responseJson));
      Navigator.push(context, MaterialPageRoute(builder: (context)=> HomePage()));
    }
    return result;
  }

}

我在做什么错了？

Answer 1

代替此：

Navigator.pushReplacement(context,MaterialPageRoute(
  builder: (context){
    return Provider<CRUDModel>.value(
      value: CRUDModel(),
      child: Login() ,
    );
  }
));

您能尝试一下吗？

Navigator.pushReplacement(context, MaterialPageRoute(
  builder: (context) {
    return ChangeNotifierProvider(
      create: (context) => CrudModel(),
      child: Login(),
    );
  }
));

如果您想在登录名内使用提供者，则可以使用Consumer或以类似方式调用

final crudModelProvider = Provider.of<CrudModel>(context);

在flutter中使用提供者依赖

1 个答案: