Libgdx: Create Item Database using JSON files

This blog post describes how to create an Item database using libgdx JSON parser and storing it in a Collections object to retrieve from.

0.) Create the JSON file

Save this as "weaponDb.json". This JSON object is used to create a list of Items in which we can grab items from.

[
    {
        "id": 1,
        "name": "Dumb Basic Sword",
    },
    {
        "id": 2,
        "name": "Bad Ass Flaming Sword",
    },
    {
        "id": 3,
        "name": "Sword of Kick Ass",
    }
]

1.) Create the test

A simple JUnit test to test our database

import com.mygdx.items.Item;
import com.mygdx.items.ItemLoader;
import org.junit.Test;

import java.io.IOException;
import java.util.ArrayList;

/*Simple Test Case*/
public class TestDb {

    @Test
    public void testDb() throws IOException {
        ItemLoader itemLoader = new ItemLoader();
        ArrayList database = itemLoader.load("weaponDb.json");
        for (Item item : database) {
            assert item.getName != null;
            System.out.println(item.getName());
        }
    }
}

2.) Create the ItemLoader

This class converts JSON objects to Java objects.

import com.badlogic.gdx.files.FileHandle;
import com.badlogic.gdx.utils.Json;
import com.badlogic.gdx.utils.JsonWriter;

import java.util.ArrayList;

public class ItemLoader {

    public ArrayList load(String db) {
        //Persist JSON object in a Collection, in my case an ArrayList
        ArrayList itemArrayList = new ArrayList();
        
        //Setup JSON requirements
        Json json = new Json();
        json.setTypeName(null);
        json.setUsePrototypes(false);
        json.setIgnoreUnknownFields(true);
        json.setOutputType(JsonWriter.OutputType.json);

        //Convert each JSON obj to an Weapon obj
        for (Object obj : json.fromJson(ArrayList.class, Weapon.class, new FileHandle(db))) {
            itemArrayList.add((Weapon) obj);
        }

        return itemArrayList;
    }
}

3.) Creating the Item Interface

The Item interface allows a player to equip different types of items that implements the Item interface. Can be armor, weapons, or accessories.

public interface Item {
    public int getId();
    public String getName();
}

4.) Create the Weapon class

This weapon class extends the Item interface. If you want to create a Armor Object just implement the Item interface when creating you armor database.

public class Weapon implements Item {

    private int id;
    private String name;
    
    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }
}