To create a shop item, make a new class that extends ShopItem (com.wearedevs.someclicker.shop.ShopItem).

import com.wearedevs.someclicker.shop.ShopItem;

public class MyShopItem extends ShopItem {
    public void onPurchase() {
        //Run Code
    }

    public int getPrice() {
        return 100;
    }

    public String getName() {
        return "My Custom Item";
    }
}

Use getPrice() and getName() to return the price and name of the item. onPurchase() is called when the user successfully buys your item.

To add the item to the shop call ShopHander.unlock(ShopItem item) with your item. You can make shop item unlock trees by calling ShopHander.unlock after purchasing an item.