Virtual Currency Shop Tutorial – Part 1 (Code)

This post contains all the code and JSON that’s been written in the YouTube video.

You can read it at your own pace, although watching the video prior to looking at this code example is recommended.

Inventory.cs

using System.Collections.Generic;
using UnityEngine;
using Boomlagoon.JSON;

public class Inventory : MonoBehaviour {
    public static Inventory Instance { get; private set; }

    private JSONObject itemsData;

    public static int SelectedItemIndex { get; private set; }

    public class ShopItem
    {
        public bool Bought, Selected;
        public int Price;
        public string Name;

        public ShopItem (bool bought, bool selected, int price, string name)
        {
            Bought = bought; Selected = selected; Price = price; Name = name;
        }
    }

    public static List<ShopItem> Items;
    public static int Coins { get; private set; }

    private void Awake()
    {
        Instance = this;

        if (!PlayerPrefs.HasKey("Items"))
        {
            PlayerPrefs.SetString("Items", "{\"Items\":[{\"name\":\"Knife\",\"bought\":true,\"selected\":true,\"price\":100},{\"name\":\"Rifle\",\"bought\":false,\"selected\":false,\"price\":500},{\"name\":\"Bow\",\"bought\":false,\"selected\":false,\"price\":150},{\"name\":\"Machete\",\"bought\":false,\"selected\":false,\"price\":200},{\"name\":\"Bazooka\",\"bought\":false,\"selected\":false,\"price\":1000}]}");
            PlayerPrefs.SetInt("Coins", 5000);
        }

        Coins = PlayerPrefs.GetInt("Coins");
        itemsData = JSONObject.Parse(PlayerPrefs.GetString("Items"));
        Items = new List<ShopItem>();

        for (int i = 0; i < itemsData.GetArray("Items").Length; i++)
        {
            Items.Add(new ShopItem(itemsData.GetArray("Items")[i].Obj.GetBoolean("bought"),
                                    itemsData.GetArray("Items")[i].Obj.GetBoolean("selected"),
                                    (int)itemsData.GetArray("Items")[i].Obj.GetNumber("price"),
                                    itemsData.GetArray("Items")[i].Obj.GetString("name")));

            if (Items[i].Selected)
                SelectedItemIndex = i;
        }
    }

    public void SelectItem(int index)
    {
        for (int i = 0; i < Items.Count; i++)
        {
            if (Items[i].Selected)
            {
                Items[i].Selected = false;
                itemsData.GetArray("Items")[i].Obj.GetValue("selected").Boolean = false;
            }
        }

        Items[index].Selected = true;
        itemsData.GetArray("Items")[index].Obj.GetValue("selected").Boolean = true;

        SelectedItemIndex = index;

        PlayerPrefs.SetString("Items", itemsData.ToString());
        PlayerPrefs.Save();
    }

    public void BuyItem(int index)
    {
        if (SubtractCoins(Items[index].Price))
        {
            Items[index].Bought = true;
            itemsData.GetArray("Items")[index].Obj.GetValue("bought").Boolean = true;
            SelectItem(index);
        }
    }

    private bool SubtractCoins(int value)
    {
        if (Coins - value < 0)
            return false;

        Coins -= value;
        PlayerPrefs.SetInt("Coins", Coins);
        return true;
    }

}

Items.json

{
	"Items": [
		{
			"name": "Knife",
			"bought": true,
			"selected": true,
			"price": 100
		},
		{
			"name": "Rifle",
			"bought": false,
			"selected": false,
			"price": 500
		},
		{
			"name": "Bow",
			"bought": false,
			"selected": false,
			"price": 150
		},
		{
			"name": "Machete",
			"bought": false,
			"selected": false,
			"price": 200
		},
		{
			"name": "Bazooka",
			"bought": false,
			"selected": false,
			"price": 1000
		}
	]
}