Switch between canvas

I have a bunch of canvases I toggle on and off.

Short answer, the main thing is to get the UnityEngine.CanvasGroup's and set the .alpha .interactable and .blocksRaycasts properties, as desired.

Long answer; Here's an Abstract class the individual controller scripts for each canvas implement, it may be of use. It also fades them in & out. Client code must implement PostMenuClose() which can be custom code called when the manu/panel is closed. Take from it what you like :)

 using UnityEngine;
 using System.Collections;
 
 public abstract class AbstractFadePanel : MonoBehaviour
 {
 
     protected UnityEngine.UI.Text[] textEls;
     protected CanvasGroup RootCanvasGroup;
     public abstract bool MenuOpen { get; protected set; }
     public abstract void PostMenuClose ();
 
     UnityEngine.UI.Image[] imageEls;
 
     bool firstTime = true;
 
     const float FADE_TIME = 0.2f;
 
     void Awake ()
     {
         RootCanvasGroup = gameObject.GetComponentsInChildren<UnityEngine.CanvasGroup> () [0];
         if (RootCanvasGroup == null)
             RootCanvasGroup = gameObject.GetComponent<UnityEngine.CanvasGroup> ();
 
         textEls = gameObject.GetComponentsInChildren<UnityEngine.UI.Text> (includeInactive: true);
         imageEls = gameObject.GetComponentsInChildren<UnityEngine.UI.Image> (includeInactive: true);
     }
 
 
     /// <summary>
     /// Toggles the visibility of the entire panel
     /// </summary>
     /// <param name="turnOn">If set to <c>true</c> turn on.</param>
     public void ToggleVisibility (bool turnOn)
     {
         // Until used, the menus may exist in the editor in a crippled state
         if (firstTime) {
             RootCanvasGroup.alpha = 1;
             RootCanvasGroup.interactable = true;
         }
 
         RootCanvasGroup.interactable = turnOn;
 
         // Remove focus from the menu so arrow keys don't also move through widgets
         //  after it's been hidden.
         UnityEngine.EventSystems.EventSystem.current.SetSelectedGameObject (null);
 
         // Fade out constituent els
         float targetAlpha = turnOn ? 1f : 0f;
 
         foreach (var t in textEls)
             t.CrossFadeAlpha (targetAlpha, FADE_TIME, false);
 
         foreach (var i in imageEls)
             i.CrossFadeAlpha (targetAlpha, FADE_TIME, false);
 
         if (turnOn)
             StartCoroutine (ForceInteractableRedraw ());
     }
         
 
     /// <summary>
     /// Closes the menu
     /// </summary>
     protected void closeMenu ()
     {
         if (!UI.UIRegistry.GetClickLock ())
             return;
 
         RootCanvasGroup.interactable = false;
         RootCanvasGroup.blocksRaycasts = false;
         MenuOpen = false;
         ToggleVisibility (turnOn: false);
         PostMenuClose ();
     }
 
 
     /// <summary>
     /// Opens the menu
     /// </summary>
     protected void openMenu ()
     {
         RootCanvasGroup.interactable = true;
         RootCanvasGroup.blocksRaycasts = true;
         MenuOpen = true;
         ToggleVisibility (turnOn: true);
     }
 
 
     /// <summary>
     /// For some reason toggling Interactable does not ensure the objects will
     /// redraw correctly to reflect the new state.  This forces it.
     /// Note Canvas.ForceUpdateCanvases() sounds like it should address this, but couldn't
     /// get it working in a quick test.
     /// </summary>
     /// <returns>The interactable redraw.</returns>
     IEnumerator ForceInteractableRedraw ()
     {
         yield return new WaitForSeconds (0.04f);
         RootCanvasGroup.interactable = false;
         RootCanvasGroup.interactable = true;
     }
 }