yichael_smartbowtv/Assets/BowArrow/Scripts/Components/CanvasBlock.cs

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

public class CanvasBlock : MonoBehaviour
{
    private static HashSet<CanvasBlock> canvasBlocks = new HashSet<CanvasBlock>(); 
    private bool hasBan = false;
    private bool valueBeforeBan;

    void OnEnable() {
        canvasBlocks.Add(this);
        this.updateGraphicRaycaster();
    }

    void OnDisable() {
        canvasBlocks.Remove(this);
        this.updateGraphicRaycaster();
    }

    void updateGraphicRaycaster() {
        ArrayList list = new ArrayList();
        foreach (CanvasBlock canvasBlock in canvasBlocks) {
            list.Add(canvasBlock);
        }
        CanvasBlockComparer canvasBlockComparer = new CanvasBlockComparer();
        list.Sort(canvasBlockComparer);
        for (int i = 0; i < list.Count; i++) {
            if (i == 0 || canvasBlockComparer.Compare(list[i], list[0]) == 0) {
                ((CanvasBlock) list[i]).resume();
            } else {
                ((CanvasBlock) list[i]).ban();
            }
        }
    }

    void ban() {
        if (this.hasBan) return;
        this.valueBeforeBan = this.GetComponent<GraphicRaycaster>().enabled;
        this.GetComponent<GraphicRaycaster>().enabled = false;
        this.hasBan = true;
        return;
    }

    void resume () {
        if (!this.hasBan) return;
        this.GetComponent<GraphicRaycaster>().enabled = this.valueBeforeBan;
        this.hasBan = false;
        return;
    }

    public class CanvasBlockComparer : IComparer  {
        public int Compare(object a, object b)  {
            return ((CanvasBlock) b).GetComponent<Canvas>().sortingOrder - ((CanvasBlock) a).GetComponent<Canvas>().sortingOrder;
        }
    }
}