如何在另一个屏幕上显示未“选中”的任务？

Question

我正在查看我的代码并想了 2 个小时，但没有运气，所以我会在这里寻求帮助。

我有一个按钮，当我按下它时，它会从列表视图中显示一个随机项目。问题是我在每个项目的列表视图上也有一个复选框。我不希望它（随机播放选中复选框的项目）只是随机播放列表视图中未选中/未选中/未完成的任务。

这是我的代码

class TaskData extends ChangeNotifier {
  List<Task> _tasks = [
    Task(name: "item1"),
    Task(name: "item2"),
    Task(name: "item3"),

  ];

  UnmodifiableListView<Task> get tasks {
    return UnmodifiableListView(_tasks);
  }

  int get taskCount {
    return _tasks.length;
  }
// <<Here is the code that shuffles through list
  Future<String> rann() async {
    return (_tasks.toList()..shuffle()).first.name;
  }
 
  void addTask(String newTaskTitle) {
    final task = Task(name: newTaskTitle);
    _tasks.add(task);
    notifyListeners();
  }

  void updateTask(Task task) {
    task.toggleDone();
    notifyListeners();
  }

在另一个脚本中我有这个

class Task {
  final String name;
  bool isDone;

  Task({required this.name, this.isDone = false});

  void toggleDone() {
    isDone = !isDone;
  }
}

在另一个脚本文件中我有这段代码

        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 20, vertical: 0),
          child: FutureBuilder(
            future: Provider.of<TaskData>(context).rann(),
            builder: (context, snapshot) {
              return Align(
                alignment: Alignment.center,
                child: Text(
                  "${snapshot.data}",
                  //softWrap: true,
                  textAlign: TextAlign.center,
                  //textWidthBasis: TextWidthBasis.longestLine,
                  style: TextStyle(
                      color: Colors.white,
                      fontSize: 30,
                      fontWeight: FontWeight.w700),
                ),
              );
            },
          ),
        ),

在另一个脚本中我有这个

class TasksList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer<TaskData>(
      builder: (context, taskData, child) {
        return ListView.builder(
          itemBuilder: (context, index) {
            final task = taskData.tasks[index];
            return TaskTile(
              taskTitle: task.name,
              isChecked: task.isDone,
              checkboxCallback: (checkboxState) {
                taskData.updateTask(task);
              },
            );
          },
          itemCount: taskData.taskCount,
        );
      },
    );
  }
}

任何帮助将不胜感激！

编辑：我也忘了包含这部分代码

class TaskTile extends StatelessWidget {
  final bool isChecked;
  final String taskTitle;
  final Function(bool?) checkboxCallback;
  final VoidCallback longPressCallback;

  TaskTile(
      {required this.isChecked,
      required this.taskTitle,
      required this.checkboxCallback,
      required this.longPressCallback});


  @override
  Widget build(BuildContext context) {
    return ListTile(
      onLongPress: longPressCallback,
      title: Text(
        taskTitle,
        // at the bottom, it sets decoration of text if isChecked is true, if its not its null
        style: TextStyle(
            decoration: isChecked ? TextDecoration.lineThrough : null),
      ),
      trailing: Checkbox(
        activeColor: Colors.blue,
        value: isChecked,
        onChanged: checkboxCallback,
      ),
    );
  }
}

Answer 1

更新：

    class TaskData extends ChangeNotifier {
        List<Task> _undoneTasksShuffled = []

        // you don't need anymore the rann method() instead you should iterate over this listView           
        UnmodifiableListView<Task> get undoneTasksShuffled => UnmodifiableListView<Task>(_undoneTasksShuffled);

        @override
        void notifyListeners() {
            //this updates _undoneTasksShuffled every time you call notifyListeners
            _undoneTasksShuffled = _tasks.where((e)=> !e.isDone).toList()..shuffle();
            super.notifyListeners();
        }

        ...
    }

---

我认为您只需要在获取随机元素之前过滤结果。你需要修改你的 rann 方法，比如

//you don't really need a future method because you don't have async code
String rann() {
    final r = Random();
    final undoneTasks = _tasks.where((e)=> !e.isDone).toList();
    //this is for avoid RangeException on list. you can return any other thing
    if(undoneTasks.isEmpty) return '';
    // i think that you don't really need to shuffle whole list, you only need a random element
    return undoneTasks[r.nextInt(undoneTasks.length)].name;
}

我希望这能解决你的问题