zombie_mp/Assets/Scripts/Menu/customDropDown.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.UI;

[RequireComponent(typeof(Button))]
public class customDropDown : MonoBehaviour
{
    public Text label;
    public GameObject dropmenu;
    public GameObject template;
    public GameObject contentParent;
    [SerializeField]
    private List<string> options;
    public UnityEvent OnChangedValue;

    public int selectedIndex;

    public void SetValue(int value){
        selectedIndex = value;
        RefreshMenu();
    }
    public void SetOptions(List<string> _options){
        options = _options;
        RefreshMenu();
    }

    public void RemoveOption(string item){
        options.Remove(item);
        RefreshMenu();
    }

    public void AddOption(string item){
        options.Add(item);
        RefreshMenu();
    }

    public List<string> GetOptions(){
        return options;
    }
    public int GetOption(string value){
        for(int i =0; i < options.Count; i++){
            if(options[i] == value){return i;}
        }

        return 0;
    }
    public void toggleDropmenu(){
        if(!dropmenu.activeSelf){
            RefreshMenu();
        }
        dropmenu.SetActive(!dropmenu.activeSelf);
        
    }
    List<GameObject> items;
    public void RefreshMenu(){
        //clean the list before adding new items
        Transform[] children = contentParent.transform.GetComponentsInChildren<Transform>();
        foreach(Transform child in children){
            if(child != contentParent.transform && child != template.transform){
                Destroy(child.gameObject);
            }
        }
        if(items==null){items = new List<GameObject>();}
        items.Clear();
        //all clear; let's go
        
        for(int i =0; i < options.Count; i++){
            string option = options[i];
            GameObject item = Instantiate(template, contentParent.transform);
            try{
            item.SetActive(true);
            item.transform.GetChild(0).GetComponent<Image>().enabled=i == selectedIndex;
            item.transform.GetChild(1).GetComponent<Text>().text = option;
            }catch{}
            int curIndex =i;
            item.GetComponent<Button>().onClick.AddListener(()=>{_onSelectedOption(curIndex);});
            items.Add(item);
            if(selectedIndex ==i){
                label.text = option;
            }
        }
        label.text = options[selectedIndex];
    }

    private void _onSelectedOption(int id){
        selectedIndex=id;
        for(int i =0; i < items.Count; i++){
            if(i != id){
                items[i].transform.GetChild(0).GetComponent<Image>().enabled=false;
            }else{
                items[i].transform.GetChild(0).GetComponent<Image>().enabled = true;
            }
        }
        dropmenu.SetActive(false);
        label.text = options[id];
        OnChangedValue.Invoke();
    }

    void Start()
    {
        GetComponent<Button>().onClick.AddListener(toggleDropmenu);
        template.SetActive(false);
        RefreshMenu();
        dropmenu.SetActive(false);
    }
}