小编Pan*_*nks的帖子

我正在尝试使用 bloc 模式创建带有 API 数据的列表视图，错误如下：

'package:flutter/src/widgets/framework.dart'：断言失败：第 5120 行 pos 12：'child == _child'：不正确。

我的列表文件：

import 'package:Instant_Feedback/Dashboard/PeopleList/bloc/bloc.dart';
import 'package:Instant_Feedback/People/strongConnection_model.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

class PeopleListing extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _PeopleListingState();
}
class _PeopleListingState extends State<PeopleListing> {
  PeopleListBloc peopleBloc;
  @override
  void initState() {
    super.initState();
    peopleBloc = BlocProvider.of<PeopleListBloc>(context);
    peopleBloc.dispatch(DisplayPeopleList());
  }

  @override
  Widget build(BuildContext context) {
    return BlocBuilder(
      bloc: peopleBloc,
      builder: (context, state){
        if (state is PeopleUninitializedState) {
          print("PeopleUninitializedState");
        } else if (state is PeopleFetchingState) {
          print("PeopleFetchingState");
        } else if (state is …

我正在学习Spring boot，遇到了一个问题。我创建了一个费用类，如下所示：

    @AllArgsConstructor
@NoArgsConstructor
@Entity
@Data
@Table(name="expense")
public class Expense {
    @Id
    private Long id;

    private Instant expensedate;

    private String description;

    private String location;

    @ManyToOne
    private Category category;

    @JsonIgnore
    @ManyToOne
    private User user;
}

现在我正在尝试创建一个控制器来添加/删除费用对象。以下方法用于创建费用对象：

@PostMapping("/expenses")
ResponseEntity<Expense> createExpense(@Valid @RequestBody Expense expense) throws URISyntaxException{
    Expense result = expenseRepository.save(expense);
    return ResponseEntity.created(new URI("/api/expense" + result.getId())).body(result);
}

但在此方法中我收到以下错误：

Expanse 类型的 getId() 方法未定义

我在登录时在我的应用程序中集成了 CircularProgressIndicator。该指示器根据需要可见，但它用白色覆盖物隐藏了我的登录屏幕。我想让它的背景透明而不是白色。我试图给 CircularProgressIndicator 的背景颜色，但它没有做任何改变。这是我的代码：

    child: !_isLoading ? _loginScreen(loginBloc.state) : Center(
      child: const SizedBox(
        width: 40,
        height: 40,
        child: CircularProgressIndicator(), 
      ),
    )

谢谢你。