在dart中将元素插入列表的开头 [英] Insert element at the beginning of the list in dart

问题描述

我只是在Flutter中创建一个简单的ToDo应用。我正在管理列表中的所有待办事项。我想在列表的开头添加任何新的待办事项。我能够使用这种解决方法来实现这一目标。有什么更好的方法吗？

I am just creating a simple ToDo App in Flutter. I am managing all the todo tasks in the list. I want to add any new todo task at the beginning of the list. I am able to use this workaround kind of thing to achieve that. Is there any better way to do this?

void _addTodoInList(BuildContext context){
    String val = _textFieldController.text;

    final newTodo = {
      "title": val,
      "id": Uuid().v4(),
      "done": false
    };

    final copiedTodos = List.from(_todos);

    _todos.removeRange(0, _todos.length);
    setState(() {
      _todos.addAll([newTodo, ...copiedTodos]);
    });

    Navigator.pop(context);
  }

推荐答案

使用 List 的> insert（）方法添加项，此处索引为 0 在开始时添加它。示例：

Use insert() method of List to add the item, here the index would be 0 to add it in the beginning. Example:

List<String> list = ["B", "C", "D"];
list.insert(0, "A"); // at index 0 we are adding A
// list now becomes ["A", "B", "C", "D"]

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