RiftToolRing.cs

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

public class RiftToolRing : MonoBehaviour {
    
    public static RiftToolRing instance { private set; get; }

    public void OnEnable()
    {
        if (instance != null) {
            throw(new System.Exception ("Error: Cannot create more than one instance of RiftToolRing!"));
        }
        instance = this;

        setAvailableTools (null);
    }

    public void OnDisable()
    {
        if( this == instance )
        {
            instance = null;
        }
    }

    public void setAvailableTools (List<ToolWidget> tools)
    {
        // Disable the toolbar if there's no tools to display:
        Transform toolBar = transform.Find ("ToolBar");
        if (tools == null || tools.Count == 0) {
            toolBar.gameObject.SetActive (false);
            return;
        } else {
            toolBar.gameObject.SetActive (true);
        }

        // Get the default tool button:
        GameObject toolButton = toolBar.Find ("ToolButton").gameObject;
        float toolButtonWidth = toolButton.GetComponent<RectTransform> ().rect.width;
        // Resize the tool bar:
        RectTransform r = toolBar.GetComponent<RectTransform> ();
        r.sizeDelta = new Vector2 ((tools.Count + 1)* toolButtonWidth + 2f, r.sizeDelta.y);
        // Add an entry for each tool:
        int i = 0;
        foreach (ToolWidget tool in tools) {
            GameObject b = Instantiate (toolButton);
            b.SetActive (true);
            b.transform.SetParent (toolButton.transform.parent, false);
            RectTransform rb = b.GetComponent<RectTransform> ();
            rb.anchoredPosition = new Vector2 (1f + i * toolButtonWidth, 0f);

            Image im = b.transform.Find ("Image").GetComponent<Image> ();
            im.sprite = tool.ToolIcon;

            Button button = b.GetComponent<Button> ();
            ToolWidget captured = tool;
            button.onClick.AddListener (() => ToolControl.instance.chooseTool (captured));
            i++;
        }

        GameObject closeButton = toolBar.Find ("CloseButton").gameObject;
        RectTransform rc = closeButton.GetComponent<RectTransform> ();
        rc.anchoredPosition = new Vector2 (1f + i * toolButtonWidth, 0f);
        Button cButton = closeButton.GetComponent<Button> ();
        cButton.onClick.RemoveAllListeners ();
        cButton.onClick.AddListener (() => ToolControl.instance.closeActiveTool ());
        closeButton.SetActive (true);
    }
}