需要关于提供程序和窗口小部件功能的错误的意见

Question

已经给我完成了一个项目，原来的人不见了。我对代码进行了一些更改，此错误在“收藏夹”页面中弹出。而且我只是想了解OG人员所做的事情。

class Favorites extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Provider<Favorites>(
    create: (context) => FavoriteModel(),
    builder: (context) {
      return favorites(context.watch<FavoriteModel>());});


      return Padding(
        padding: const EdgeInsets.all(10.0),
        child: Column(
          children: <Widget>[
            Text("Favorite Houses"),
            Expanded(
              child: ListView.builder(
                  physics: BouncingScrollPhysics(),
                  itemCount: favorites.houses.length,
                  itemBuilder: (context, index) {
                    return GestureDetector(
                      onTap: () {
                        Navigator.of(context).push(
                          MaterialPageRoute(
                              builder: (_) => DetailScreen(
                                    favorites.houses[index],
                                  )),
                        );
                      },
                      child: Container(
                          padding: EdgeInsets.all(17),
                          height: 250,
                          child: Stack(
                            children: <Widget>[
                              Align(
                                alignment: Alignment.centerRight,
                                child: Container(
                                  width: MediaQuery.of(context).size.width *
                                      .5,
                                  decoration: BoxDecoration(
                                      borderRadius: BorderRadius.all(
                                          Radius.circular(20)),
                                      image: DecorationImage(
                                          image: ExactAssetImage(favorites
                                              .houses[index].imagePath),
                                          fit: BoxFit.cover),
                                      boxShadow: [
                                        BoxShadow(
                                          blurRadius: 7,
                                          spreadRadius: 1,
                                          color: Colors.black12,
                                        )
                                      ]),
                                  child: Stack(
                                    fit: StackFit.expand,
                                    children: <Widget>[
                                      Container(
                                        decoration: BoxDecoration(
                                            gradient: LinearGradient(
                                              colors: [
                                                Colors.transparent,
                                                Colors.transparent,
                                                Colors.black87
                                              ],
                                              begin: Alignment.topCenter,
                                              end: Alignment.bottomCenter,
                                            ),
                                            borderRadius: BorderRadius.all(
                                                Radius.circular(20))),
                                      ),
                                      Align(
                                        alignment: Alignment.bottomLeft,
                                        child: Padding(
                                          padding: EdgeInsets.only(
                                              bottom: 12,
                                              left: 40,
                                              right: 12),
                                          child: Row(
                                            mainAxisAlignment:
                                                MainAxisAlignment
                                                    .spaceBetween,
                                            children: <Widget>[
                                              Container(
                                                width:
                                                    MediaQuery.of(context)
                                                            .size
                                                            .width *
                                                        .2,
                                                child: Text(
                                                  "${favorites.houses[index].titleTxt}",
                                                  style: TextStyle(
                                                      fontWeight:
                                                          FontWeight.bold,
                                                      color: Colors.white),
                                                ),
                                              ),
                                              Container(
                                                padding: EdgeInsets.all(6),
                                                child: FavoriteWidget(
                                                    favorites
                                                        .houses[index]),
                                                // Icon(
                                                //   Icons.directions,
                                                //   color: Colors.white,
                                                //   size: 20,
                                                // ),
                                                decoration: BoxDecoration(
                                                  color: Colors.black38,
                                                  borderRadius:
                                                      BorderRadius.all(
                                                          Radius.circular(
                                                              100)),
                                                ),
                                              )
                                            ],
                                          ),
                                        ),
                                      )
                                    ],
                                  ),
                                ),
                              ),
                              Align(
                                alignment: Alignment.centerLeft,
                                child: Container(
                                  width: MediaQuery.of(context).size.width *
                                      .43,
                                  height: 200,
                                  padding: EdgeInsets.all(12),
                                  decoration: BoxDecoration(
                                      color: Colors.white,
                                      borderRadius: BorderRadius.all(
                                          Radius.circular(20)),
                                      boxShadow: [
                                        BoxShadow(
                                          blurRadius: 7,
                                          spreadRadius: 1,
                                          color: Colors.black12,
                                        )
                                      ]),
                                  child: Column(
                                    crossAxisAlignment:
                                        CrossAxisAlignment.start,
                                    mainAxisAlignment:
                                        MainAxisAlignment.spaceBetween,
                                    children: <Widget>[
                                      Row(
                                        crossAxisAlignment:
                                            CrossAxisAlignment.end,
                                        children: <Widget>[
                                          //                       Icon(
                                          //                         Icons.attach_money,
                                          //                         size: 18,
                                          //                       ),
                                          Text(
                                            "${favorites.houses[index].perNight}/",
                                            style: TextStyle(
                                                fontSize: 16.0,
                                                fontWeight:
                                                    FontWeight.bold),
                                          ),
                                          Text(
                                            "Year",
                                            style: TextStyle(
                                                fontSize: 16.0,
                                                fontWeight:
                                                    FontWeight.bold),
                                          ),
                                        ],
                                      ),
                                      Text(
                                        "${favorites.houses[index].subTxt}",
                                        style: TextStyle(
                                          color: Colors.black38,
                                        ),
                                      ),
                                      Row(
                                        children: <Widget>[
                                          //RatingBar
                                          Text(
                                            "${favorites.houses[index].reviews}",
                                            style: TextStyle(
                                                fontSize: 10.0,
                                                fontWeight:
                                                    FontWeight.bold),
                                          ),
                                        ],
                                      ),
                                      // Row(
                                      //   children: <Widget>[],
                                      // ),
                                      Wrap(
                                        children: <Widget>[
                                          ...favorites
                                              .houses[index].features
                                              .map((feature) {
                                            return Container(
                                              padding: EdgeInsets.all(6.0),
                                              margin: EdgeInsets.only(
                                                  bottom: 6, right: 6),
                                              decoration: BoxDecoration(
                                                  borderRadius:
                                                      BorderRadius.all(
                                                          Radius.circular(
                                                              50)),
                                                  color: Colors.black),
                                              child: Text(
                                                feature,
                                                style: TextStyle(
                                                    fontSize: 12,
                                                    color: Colors.white),
                                              ),
                                            );
                                          })
                                        ],
                                      ),
                                    ],
                                  ),
                                ),
                              )
                            ],
                          )),
                    );
                  }),
            ),
          ],
        ),
      );

      // return Container(
      //   margin: const EdgeInsets.all(5),
      //   padding: const EdgeInsets.all(8.0),
      //   child: ListView.builder(
      //       itemCount: house.houses.length,
      //       itemBuilder: (context, index) {
      //         return ImageWidget(house.houses[index], house.houses[index].id - 1,
      //             Constants.imageList);
      //       }),
      // );
    });
     }
     }

在main.dart中找到了这块金块

  runApp(ChangeNotifierProvider(
  create: (context) => FavoriteModel(), child: MyApp()));
 FlutterError.onError = (FlutterErrorDetails details) {
  FlutterError.dumpErrorToConsole(details);
if (kReleaseMode) exit(1);
};
runApp(MyApp());
}

因此，基本上，OC创建了收藏夹页面和收藏夹模型，并尝试将其与提供者链接。至少了解我所掌握的知识，但对Flutter / Dart来说，这仍然是新事物，并且至今为止还是很喜欢。