如何为与提供商合作的列表实现 ChangeNotifier？

Question

我想为我的应用程序实现 Provider，经过一些研究，我发现我必须为我的 Data 类实现 ChangeNotifier，以便在“天”更改时更新 UI。

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我见过有人在 setter 方法中编写 notificationListeners() 但总是针对单个属性而不是针对列表。什么是正确的实施？

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谢谢 ！

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这是我的班级和清单：

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class Data with ChangeNotifier {\n  List<Day> days = [\n    Day(\n      name: \'Monday\',\n      transactions: [\n        Transaction(\n          isExpense: true,\n          name: \'Pizza\',\n          transactionType: TransactionType.food,\n          amount: \'120\xe2\x82\xac\',\n        ),\n        Transaction(\n          isExpense: true,\n          name: \'EDEKA\',\n          transactionType: TransactionType.payment,\n          amount: \'120\xe2\x82\xac\',\n        ),\n      ],\n    ),\n    Day(\n      name: \'Tuesday\',\n      transactions: [\n        Transaction(\n          isExpense: true,\n          name: \'Sushi\',\n          transactionType: TransactionType.food,\n          amount: \'120\xe2\x82\xac\',\n        ),\n        Transaction(\n          isExpense: true,\n          name: \'Lidl\',\n          transactionType: TransactionType.payment,\n          amount: \'120\xe2\x82\xac\',\n        ),\n        Transaction(\n          isExpense: false,\n          name: \'Einkommen\',\n          transactionType: TransactionType.payment,\n          amount: \'120\xe2\x82\xac\',\n        ),\n      ],\n    ),\n  ];\n}\n

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Answer 1

Todo App是一个很好的示例处理List<Taks>
您可以参考https://dev.to/shakib609/create-a-todos-app-with-flutter-and-provider-jdh
完整示例github代码https://github.com/ shakib609/todos-flutter/tree/master/lib

代码片段

class Task {
  String title;
  bool completed;

  Task({@required this.title, this.completed = false});

  void toggleCompleted() {
    completed = !completed;
  }
}

class TodosModel extends ChangeNotifier {
  final List<Task> _tasks = [];

  UnmodifiableListView<Task> get allTasks => UnmodifiableListView(_tasks);
  UnmodifiableListView<Task> get incompleteTasks =>
      UnmodifiableListView(_tasks.where((todo) => !todo.completed));
  UnmodifiableListView<Task> get completedTasks =>
      UnmodifiableListView(_tasks.where((todo) => todo.completed));

  void addTodo(Task task) {
    _tasks.add(task);
    notifyListeners();
  }

  void toggleTodo(Task task) {
    final taskIndex = _tasks.indexOf(task);
    _tasks[taskIndex].toggleCompleted();
    notifyListeners();
  }

  void deleteTodo(Task task) {
    _tasks.remove(task);
    notifyListeners();
  }
}

工作演示