How to deserialize an array of named objects in an object using the Unity JsonUtility?

Question

JSON

Have a good time, benevolent! Brother, help me out, you need to deserialize JSON into C # Object using standard Unity tools, below I will give an example of what I want. You just need to suggest how to competently implement a class for serializing / deserializing a JSON string.

JSON example

{
"cars": [
  {"cars_bigs": [{"force": 500, "weight": 1000}, {"force": 1000, "weight": 4000}]},
  {"cars_smaller": [{"force": 100, "weight": 800}, {"force": 300, "weight": 400}]}
]
}

An example of my failed class implementation

[Serializable]
public class CarsResult {
  public CarItem[] cars;
}

[Serializable]
public class CarItem {
  public string CarType;
  public Car[] CarObjects;
}

[Serializable]
class Car {
  public int force;
  public int weight
}

PS My implementation is not working, please, if it's not difficult, then explain why and how to properly deserialize such a JSON response

Answer 1

1. Your json looks like this:

- cars
  - cars_bigs
    - force: 500
      weight: 1000
    - force: 1000
      weight: 4000
  - cars_smaller
    # и так далее

So you need objects like this:

class CarsResult {
  public CarItem[] Cars { get; set; }
}
class CarItem {
  // К сожалению, нельзя на уровне системы типов выразить "Объект, у которого есть либо поле А либо поле Б"
  // Так что придётся указать оба поля
 // И нельзя это разрулить на уровне настроек сериализатора, если не придумывать кастомный сериализатор (не знаю, можно ли кастомизировать юнитивский)
  public Car[] BigCars { get; set; }
  public Car[] SmallCars { get; set; }
}
class Car {
  public int Force { get; set; }
  public int Weight { get; set; }
}

PS: In English, adjectives are placed before nouns and do not have a number. So "big cars" is "big cars" but not "Cars bigs". And "smaller cars" are "Smaller cars"
PPS: I hope you can figure out how to specify the necessary names after reading the documentation ..

Answer 2

The standard json is either semi-working, or I don’t understand something, I also had problems with it and the output was the newtonsoft library, it seems that the unit immediately has it, try it, everything worked with it

Answer 3

1) Don't use Unity's standard JSON - it's terrible, it doesn't work with nesting levels greater than 1.
2) Newtonsoft is much better, the Unity team themselves included it in their packages.
3) To read a class in JSON, you need to create it with the [Serializable] attribute. Also note that not all base classes/structs in Unity can be serialized. For example, there may be problems with Vector3, in some places you may need to write your own class for this.