removeWhere()方法不洗掉資料

我正在構建一個食物食譜應用程式，用戶可以在其中瀏覽各種食譜。功能是，當用戶點擊洗掉按鈕時，該專案將不會顯示在串列中。我導航mealId到上一個螢屏，即串列螢屏通過

floatingActionButton: FloatingActionButton(
    onPressed: () {
      Navigator.of(context).pop(mealId);
    },
    child: const Icon(Icons.delete),
  ),

我在向后小部件中收到 pop() 值，例如：

void selectMeal(BuildContext context) {
    Navigator.of(context)
        .pushNamed(MealsDetailsScreen.routeName, arguments: id)
        .then((result) {
      if (result != null) {
        removeItem(result);
        print(result); // it prints the expected id
      }
    });
  }

在完全附加的代碼中，我想通過以下方式洗掉專案詳細資訊 mealId

void _removeMeal(String mealId) {
    setState(() {
      print("$mealId from didChangedDependancies"); //it also prints the expected id
      displayedMeals.removeWhere((meal) => meal.id == mealId);
    });
  }

我將函式設定為洗掉的代碼：

import 'package:flutter/material.dart';

import '../models/meals.dart';
import '../models/dummy_data.dart';
import '../widgets/meal_item.dart';

class CategoryMealaScreen extends StatefulWidget {
  static const routeName = '/category-meals';
  @override
  State<CategoryMealaScreen> createState() => _CategoryMealaScreenState();
}

class _CategoryMealaScreenState extends State<CategoryMealaScreen> {
  late String categoryTitle;
  late List<Meal> displayedMeals;
  var _loadedInitData = false;

  @override
  void initState() {
    super.initState();
  }

  @override
  void didChangeDependencies() {
    if (!_loadedInitData) {
      final routeArgs =
          ModalRoute.of(context)!.settings.arguments as Map<String, String>;

      categoryTitle = routeArgs['title'].toString();
      final categoryId = routeArgs['id'];
      displayedMeals = dummyMeals.where((meal) {
        return meal.categories.contains(categoryId);
      }).toList();
      _loadedInitData = true;
    }
    super.didChangeDependencies();
  }

  void _removeMeal(String mealId) {
    setState(() {
      print("$mealId from didChangedDependancies");
      displayedMeals.removeWhere((meal) => meal.id == mealId);
    });
  }

  @override
  Widget build(BuildContext context) {
    final routeArgs = // received data from widget CategoryItems()
        ModalRoute.of(context)!.settings.arguments as Map<String, String>;

final categoryTitle = routeArgs['title'];
final categoryId = routeArgs['id'];
final displayedMeals = dummyMeals.where((meal) {
  return meal.categories.contains(categoryId);
}).toList();

return Scaffold(
  appBar: AppBar(
    title: Text(categoryTitle.toString()),
  ),
  body: ListView.builder(
      itemCount: displayedMeals.length,
      itemBuilder: (ctx, index) {
        return MealItem(
          id: displayedMeals[index].id,
          title: displayedMeals[index].title,
          imageUrl: displayedMeals[index].imageUrl,
          complexity: displayedMeals[index].complexity,
          affordability: displayedMeals[index].affordability,
          duration: displayedMeals[index].duration,
          removeItem: _removeMeal,
        );
      }),
    );
  }
}

控制臺上沒有顯示錯誤。如果你們幫幫我，我會很高興的！非常感謝??

uj5u.com熱心網友回復：

final displayedMeals在您的build方法中洗掉。

改用方法displayedMeals之外的變數build。

標籤：扑 镖

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