如何在 Back4App 中创建对象列表？

问题描述

我在我的应用程序中使用 back4app 并且我有一个这样的类叫做 Meal：

这是我的代码片段：

class EatenMeals with ChangeNotifier {
  List<Meal> _eatenMeals = [];

  List<Meal> get eatenMeals {
    return [..._eatenMeals];
  }

  void addMeal(Meal meal) {
    var newMeal = Meal(
        id: meal.id,cal: meal.cal,catId: meal.catId,title: meal.title,duration: meal.duration,affordability: meal.affordability,imageUrl: meal.imageUrl,ingredients: meal.ingredients,isBreakfast: meal.isDinner,isDinner: meal.isDinner,isLunch: meal.isLunch,steps: meal.steps);

    _eatenMeals.add(newMeal);
  }
}

现在我想创建一个包含 Meals 对象列表的类。 并附加到用户我如何实现这一点？

解决方法

结帐Parse Server Custom Objects。以下是您如何为膳食创建自定义对象的示例。

class Meal extends ParseObject implements ParseCloneable {
  Meal() : super(_keyTableName);
  Meal.clone() : this();

  /// Looks strangely hacky but due to Flutter not using reflection,we have to
  /// mimic a clone
  @override
  clone(Map map) => Meal.clone()..fromJson(map);

  /// Colum names
  static const String _keyTableName = 'Meal';
  static const String keyCatId = 'catId';
  static const String keyTitle = 'title';
  static const String keyImgUrl = 'imgUrl';
  static const String keyIngredients = 'ingredients';
  static const String keySteps = 'steps';
  static const String keyCalorie = 'calorie';
  static const String keyDuration = 'duration';
  static const String keyAffordability = 'affordability';
  static const String keyIsBreakfast = 'isBreakfast';
  static const String keyIsLunch = 'isLunch';
  static const String keyIsDinner = 'isDinner';

  /// Getter & Setters
  List<String> get catId => get<List<String>>(keyCatId);
  set name(List<String> catId) => set<List<String>>(keyCatId,catId);
  
  String get title => get<String>(keyTitle);
  set title(String title) => set<String>(keyTitle,title);
  
  Strin> get imgUrl => get<String>(keyImgUrl);
  set imgUrl(String imgUrl) => set<String>(keyImgUrl,imgUrl);
  
  List<String> get ingredients => get<List<String>>(keyIngredients);
  set ingredients(List<String> ingredients) => set<List<String>>(keyIngredients,ingredients);
  
  List<String> get steps => get<List<String>>(keySteps);
  set steps(List<String> steps) => set<List<String>>(keySteps,steps);
  
  num get calorie => get<num>(keyCalorie);
  set calorie(num calorie) => set<num>(keyCalorie,calorie);
  
  num get duration => get<num>(keyDuration);
  set affordability(num duration) => set<num>(keyDuration,duration);
  
  String get affordability => get<String>(keyAffordability);
  set name(String affordability) => set<String>(keyAffordability,affordability);
  
  bool get isBreakfast => get<bool>(keyIsBreakfast);
  set isBreakfast(bool isBreakfast) => set<bool>(keyIsBreakfast,isBreakfast);
  
  bool get isLunch => get<bool>(keyIsLunch);
  set isLunch(bool isLunch) => set<bool>(keyIsLunch,isLunch);
  
  bool get isDinner => get<bool>(keyIsDinner);
  set isDinner(bool isDinner) => set<bool>(keyIsDinner,isDinner);
}

然后你必须注册这个子类。

Parse().initialize(
   ...,registeredSubClassMap: <String,ParseObjectConstructor>{
     'Meal': () => Meal(),},);