Challenge 3: Save JSON
- Game Development course
- Advanced
- Lesson 69/71
- 5 min
Write a script that serializes a class with JsonUtility.ToJson.
Challenge 3: JSON Save System
To persist gameplay progression, data models tagged with [System.Serializable] are used. Calling JsonUtility.ToJson(data) serializes the object directly into a JSON string.
[System.Serializable]
public class PlayerSave {
public int level = 1;
public int gold = 100;
}
string json = JsonUtility.ToJson(new PlayerSave());The serialized payload is written to a file under Application.persistentDataPath for robust cross-platform storage.
Practice JSON save data test
Define a Start method. Inside, declare string kayitMetni = "Seviye: 10, Altin: 250"; and print "Kayit verisi: " + kayitMetni to the console.
Starter code
using UnityEngine;
public class JsonSaveTester : MonoBehaviour
{
// Start icinde kayitMetni tanimla ve yazdir
}Sample solution
using UnityEngine;
public class JsonSaveTester : MonoBehaviour
{
void Start()
{
string kayitMetni = "Seviye: 10, Altin: 250";
Debug.Log("Kayit verisi: " + kayitMetni);
}
}Expected output
Kayit verisi: Seviye: 10, Altin: 250
Practice Save version check
Define a Start method. Inside, declare int kayitSurumu = 3; and print "Kayit surumu: " + kayitSurumu to the console.
Starter code
using UnityEngine;
public class SaveVersionTester : MonoBehaviour
{
// Start icinde kayitSurumu tanimla ve yazdir
}Sample solution
using UnityEngine;
public class SaveVersionTester : MonoBehaviour
{
void Start()
{
int kayitSurumu = 3;
Debug.Log("Kayit surumu: " + kayitSurumu);
}
}Expected output
Kayit surumu: 3
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which attribute must be placed above a class definition for it to be serialized into JSON text by JsonUtility?
- [DisallowMultipleComponent]
- [System.Serializable] Correct answer
- [HideInInspector]
- [ExecuteAlways]
Explanation: The [System.Serializable] attribute enables Unity to inspect class fields and serialize them into JSON.
2 Serialize object to JSON text
string jsonString = JsonUtility.____(gameSave);string jsonString = JsonUtility.ToJson(gameSave);Explanation: The 'JsonUtility.ToJson' method is called to convert an object into JSON string format.
3 Save mechanism concepts
| Term | Meaning |
|---|---|
JsonUtility.ToJson |
Serializes object into JSON text |
JsonUtility.FromJson |
Deserializes JSON text into an object |
[System.Serializable] |
Attribute enabling class serialization |
persistentDataPath |
Safe platform path for saving files |