GUI API

# plugins/YourPlugin/menus/main.yml
title: "&0Main Menu"
size: 54
items:
  close:
    material: BARRIER
    slot: 53
    name: "&cClose"
    on_left_click:
      - "close"

  diamond:
    material: DIAMOND
    slot: 0
    amount: 1
    name: "&bDiamond"
    lore:
      - "Shiny, precious gem"
    on_left_click:
      - "console give %player% diamond 64"
      - "message &aYou received diamonds!"
      - "opengui shop"

# plugins/YourPlugin/menus/shop.yml
title: "&aShop"
size: 27
items:
  back:
    material: ARROW
    slot: 26
    name: "&7Back"
    on_left_click:
      - "opengui main"

import io.github.chi2l3s.nextlib.api.gui.GuiManager;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;

public class MyPlugin extends JavaPlugin {
  private GuiManager guiManager;

  @Override
  public void onEnable() {
    guiManager = new GuiManager(this);

    // Load all *.yml from /menus
    java.io.File menusFolder = new java.io.File(getDataFolder(), "menus");
    guiManager.loadFromFolder(menusFolder);

    // Simple command to open a GUI by file name (without .yml)
    getCommand("menu").setExecutor((sender, cmd, label, args) -> {
      if (sender instanceof Player player) {
        String id = args.length > 0 ? args[0] : "main"; // main -> main.yml
        guiManager.openGui(player, id);
      }
      return true;
    });
  }
}