SettingsCanvas Template

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

/*
 http://stackoverflow.com/questions/36809687/ui-canvas-image-with-ui-buttons
 */

public class SettingsCanvas : MonoBehaviour
{
    public Button backButton;

    public Canvas mainMenuCanvas;
    public Canvas pauseCanvas;

    SettingsCalledFrom settingsCalledFrom = SettingsCalledFrom.calledFromMainMenu;

    // Use this for initialization
    void OnEnable()
    {
        //Register Button Events
        backButton.onClick.AddListener(() => buttonCallBack(backButton));
    }

    private void buttonCallBack(Button buttonPressed)
    {
        //Back Button
        if (buttonPressed == backButton)
        {
            //Hide Settings Canvas
            gameObject.SetActive(false);

            //Show MainMenu Canvas
            if (settingsCalledFrom == SettingsCalledFrom.calledFromMainMenu)
            {

                mainMenuCanvas.gameObject.SetActive(true);
            }
            //Show Pause Canvas
            else if (settingsCalledFrom == SettingsCalledFrom.calledFromPauseMenu)
            {

                pauseCanvas.gameObject.SetActive(true);
            }
        }
    }

    //Must call this after this script is enabled so that the Back Button will function well
    public void setCalledFrom(SettingsCalledFrom _settingsCalledFrom)
    {
        settingsCalledFrom = _settingsCalledFrom;
    }

    void OnDisable()
    {
        //Un-Register Button Events
        backButton.onClick.RemoveAllListeners();
    }
}

//Used to determine where this settings UI is called from so that back button will return there when clicked
public enum SettingsCalledFrom
{
    calledFromMainMenu, calledFromPauseMenu
}