Version: 2019.1
public bool IsInteractable ();

Description

UI.Selectable.IsInteractable.

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // required when using UI elements in scripts

public class Example : MonoBehaviour { public Button startButton;

void Update() { if (!startButton.IsInteractable()) { Debug.Log("Start Button has been Disabled"); } } }