EventSystemManaged

EventSystemManaged.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class EventSystemManaged : EventSystem
{
    static Stack<EventSystem> ms_PrevEventSystem = new Stack<EventSystem>();
    static bool ms_Forced = false;

    protected override void OnEnable()
    {
        if(!ms_Forced)
            SaveAndDisableCurrent();

        base.OnEnable();
    }

    protected override void OnDisable()
    {
        base.OnDisable();

        if (!ms_Forced)
            RestorePrevious();
    }

    static void SaveAndDisableCurrent()
    {
        var current = EventSystem.current;
        ms_PrevEventSystem.Push(current);
        if (current)
        {
            ms_Forced = true;
            current.enabled = false;
            ms_Forced = false;
        }
    }

    static void RestorePrevious()
    {
        Debug.Assert(ms_PrevEventSystem.Count > 0);
        var prev = ms_PrevEventSystem.Pop();
        if (prev)
        {
            ms_Forced = true;
            prev.enabled = true;
            ms_Forced = false;
        }
    }
}