Flutter Bloc Equatable 状态，在所有状态类中具有一个共同属性

Question

我正在尝试找出定义我的 Search Bloc 状态以在所有状态类中保留 text 属性（搜索键）的最佳方法。

目前，它看起来像这样：

import 'package:equatable/equatable.dart';
import 'package:project/models/searchResults.dart';

class SearchState extends Equatable {
  SearchState([List props = const []]) : super(props);
}

class SearchStateEmpty extends SearchState {
  final String text;
  SearchStateEmpty({this.text});
  @override
  String toString() => 'SearchStateEmpty';
}

class SearchStateLoading extends SearchState {
  final String text;
  SearchStateLoading({this.text});
  @override
  String toString() => 'SearchStateLoading';
}

class SearchStateSuccess extends SearchState {
  final String text;
  final List<RestaurantSearchItem> items;

  SearchStateSuccess({this.text, this.items}) : super([text, items]);

  @override
  String toString() => 'SearchStateSuccess { items: ${items.length} }';
}

class SearchStateError extends SearchState {
  final String text;
  final String error;

  SearchStateError({this.text, this.error}) : super([text, error]);

  @override
  String toString() => 'SearchStateError';
}

有没有比在所有状态类中定义 text 属性更好的方法？

如果我不必每次事件没有它时都使用currentState 属性，这不会像现在那么糟糕。例如：

SearchStateEmpty(text: currentState.text);
...
SearchStateLoading(text: event.text);
...
SearchStateSuccess(text: currentState.text, items: results.items);

我一直在寻找 Flutter 文档中的示例，但我能找到的只是我应该使用不同的 bloc 或放弃 equatable（我想保留它，因为它非常好）。

任何带有示例的建议都将受到高度赞赏。谢谢。

Answer 1

我这样做的方式有点像反模式。在一些帮助下，我能够找到一种更简洁的方式来在我的状态类中使用当前状态。

代码现在看起来像这样：

class SearchState extends Equatable {
  final String text;
  SearchState(this.text,
      [List<RestaurantSearchItem> items = const [], String error = ''])
      : super([text, items, error]);
}

class SearchStateEmpty extends SearchState {
  SearchStateEmpty({String text})
      : super(text); // Here I want to use text from SearchState

  SearchStateEmpty.fromState(SearchState state) : super(state.text);

  @override
  String toString() => 'SearchStateEmpty';
}

class SearchStateLoading extends SearchState {
  final String text;

  SearchStateLoading({this.text})
      : super(text); // Here I  want to set text that comes from event

  @override
  String toString() => 'SearchStateLoading';
}

class SearchStateError extends SearchState {
  final String error;

  SearchStateError({this.error, String text}) : super(text, [], error);
  // Text comes from SearchState, error comes from event

  SearchStateError.fromState(SearchState state, {this.error})
      : super(state.text, [], error);

  @override
  String toString() => 'SearchStateError';
}

class SearchStateSuccess extends SearchState {
  final List<RestaurantSearchItem> items;

  SearchStateSuccess({this.items, String text}) : super(text, items, null);

  SearchStateSuccess.fromState(SearchState state, {this.items})
      : super(state.text, items, null);

  @override
  String toString() => 'SearchStateSuccess { items: ${items.length} }';
}